By Tim Gibbons, M.S., Endurance Training Coordinator Sport Science and Technology Division, U.S. Olympic Committee

This is an edited version of a USOC sports science study which gathers data regarding common elements of internationally successful programs in the biathlon, cross country skiing and Kenyan distance running and attempts to apply them to U.S. distance running.

INTRODUCTION
Internationally successful endurance athletes are the product of genetic ability and many years of systematic training. Inherited endowment and the genetic ability to positively adapt to training are important considerations when discussing endurance performance; however, training of the genetic gifts at certain stages of growth and development may ultimately be more important. At the current level of international competition in endurance sport, one can only succeed after years of effective training, regardless of innate ability.
There are many common characteristics that are attributed to the development of internationally successful endurance athletes. These factors include:

1. Physical activity during childhood and early adolescence.

2. Age of sport specialization.

3. Long-term development.

4. Training volume and intensity during adolescence and young adulthood.

5. High-quality coaching.

6. Training partners and team atmosphere.

The majority of these factors if not all of them are found in successful biathlon (cross country skiing and rifle marksmanship) programs in Germany, distance running programs in Kenya, and cross country ski programs in Finland, Norway, and Sweden. Local and national programs in these countries have exerted a strong presence in their respective sports over several decades. Currently, all countries list several athletes in top ten overall world rankings in each sport. In an increasingly competitive sports world, these factors are necessary for optimal development to occur.
In order to understand optimal models of athlete development, this paper will outline the time course and developmental patterns that are typical of the world’s best winter endurance athletes. Utilizing articles from the scientific literature and data from surveys and interviews with athletes, coaches, and sport scientists this paper will compare and contrast the characteristics that are common to winter endurance sports and distance running.

CRITICAL MILESTONES IN PERFORMANCE
In order to understand optimal models of athlete development, USOC sport scientists examined the time course and developmental patterns of the world’s best endurance athletes. Data from recent research in biathlon and cross country skiing (Gibbons, 1997a and 1998b) demonstrate the importance of high quality junior programs from other countries in order to achieve success at the highest levels of international competition.
These data are compiled from the top men and women in biathlon and cross country skiing who have placed in the top three at World Cup, World Championship, and Olympic competition in the last ten years. Performance data were obtained from the International Biathlon Union and International Ski Federation.
Figure 1 illustrates the age at each performance milestone in the development of these athletes. Biathletes and cross country skiers exhibit similar patterns of ascendancy at World Cup and Olympic competition. Average age of the first competition is 11.6 years and specialization in the sport begins at the average age of 16.5 years. Once an athlete begins World Cup competition (average age of 21.8 years) or achieves a top 25 World Cup result (average age of 22.6 years), there is a linear progression in performance improvement. A top 10 placing occurs at age 23.3 years and a top three finish at age 24.3 years.

These data suggest that the preparation period from age 16 – 24 years is crucial for success. This is a “critical period” for physical and technical development. In these sports, over two-thirds of the athletes who achieved a top-three finish in a World Cup or World Championship event also finished in the top ten at a Junior World Championship event. A top placing at Junior Worlds is one indicator in a long-term development plan that seeks sustained competitive excellence.
Performance data from the 1998 Olympic Winter Games suggest there may be several roads to top performance (Gibbons, 1998a and 1999). Figure 2 illustrates the number of years needed in World Cup competition to achieve a top overall ranking in biathlon and cross country ski athletes who placed in the top 15 at the 1998 Olympic Winter Games in Nagano, Japan.

Within biathlon and cross country skiing, it takes an average of five years of World Cup competition to achieve a top-25 overall World Cup ranking. The top athletes ascend to a top-10 ranking within their first year of competition on the World Cup circuit. For some athletes, it may take seven years to achieve a top-25 overall World Cup ranking. These three roads to top performance reflect differences in genetic ability of the athlete, the number of years training, the volume of training, and competitive experience.
Common to all athletes is a period of four to six years of systematic training that precedes top performance. These data suggest that among the top 15 Olympic finishers, there is a long, continuous development, which is needed to attain a top-25 overall World Cup ranking.

INTERNATIONAL MODELS OF ATHLETE DEVELOPMENT
There are three distinct development phases that World Cup medallists in biathlon and cross country skiing move through in order to achieve sustained competitive excellence. Figure 3 depicts three phases of development of the top three finishers in World Cup biathlon and cross country skiing.

Currently, anecdotal evidence suggests that successful endurance athletes come from a childhood with a variety of activities. This multilateral approach includes cardiovascular activity, motor skill development, and games. In a survey of medal-winning athletes on the Biathlon World Cup from 1987-1997, the respondents reported participation in a variety of sports from 8-15 years old (Gibbons, 1997a). The most frequently reported sports were track & field, soccer, gymnastics, swimming, and cross country skiing. Activity ranged from 5-10 hours per week over a la-month period. These data indicate that a large amount of physical activity and general skill development were present in the multilateral development phase.
In the second phase of development, systematic year-round training is the foundation for successful sport gymnasiums (sport high schools) in Germany and Sweden (Gibbons, 1999b and 1998b). In Germany, athletes enter sport gymnasiums at 14 years and in Sweden at 17 years of age, respectively. In most cases, this marks the beginning of sport specialization.
Specializing in one sport during the mid -to-late teenage years is crucial to allow for structured training with a long-term perspective. Improvement in performance is due to progressive, sequential training.
In the final phase of development, World Cup Performance, athletes are provided support that allows for a continued improvement in training and subsequent performance. In many programs, support comes from excellent coaching and sport science expertise.

APPLICATION TO THE SPORT OF TRACK AND FIELD
From the data on the development of medal winners in the sports of biathlon and cross country skiing, there emerges a clear picture on the time course and developmental pattern of the world’s best winter endurance athletes. These athletes are successful because of many years of progressive, sequential training.
Athletes in biathlon and cross country skiing who are successful on the World Cup circuit have in common a four-to-six-year period of systematic training. This training occurs between the ages of 16 – 26 years.
Performance data from the 1999 Track & Field World Championships suggests a similar path of development in distance running. Biographical data from the International Amateur Athletics Federation and USA Track & Field allows us to track the progression of performance in distance runners from the 1999 World Championships and U.S.. Championships. Tables 1 and 2 illustrate the ages and performance times at critical milestones in the top ten finishers from the 1999 Track & Field World Championships and 1999 USA Track & Field Championships in the 5000m and 10,000m.

Each biography lists the progression of performances across several race distances (1500m – 10,000m) from international events. Performance times and international starting ages were calculated for the women’s and men’s 5000m and 10,000m events.
Average age for the first international start for the women’s 5000m and 10,000m, events was 21.7 years old and performance times averaged 15:39 and 32:15, respectively. Standard deviation was 2.8 years for the 5000m and 6.3 years for the 10,000m, pointing out a small variability for the 5000m run. Performance times improved an average of 5.0 and 3.1 per cent in a four-year period in the women’s 5000m and 10,000m, respectively. Average age of the finalists in the women’s 5000m and 10,OOOm in the 1999 World Championships ranged between 25.5 – 26.0 years old.
Average age for the first international start for the men’s 5000m and 10,000m events was 19.6 (± 2.6) and 20.4 (± 2.6) years old, and performance times averaged 13:32 and 28: 17, respectively. Performance times improved an average of 4.0 percent in a four-year period in the 5000m and 10,000m, respectively. Average age of the finalists in the men’s 5000m and 10,000m in the 1999 World Championships ranged between 25.2 and 25.8 years old.
These data demonstrate that at the age of 21 years, both male and female distance runners boast impressive performance times. In three of the four race distances, the standard deviation for the starting age was approximately 2.5 years indicating a small variability at this age.
Over a four-year period, performance times improved roughly by one per cent per year. We can speculate that for the top ten finishers to initially reach the performance times at 21 years old requires several years of systematic training. The performance trends of the top ten finishers of the 1999 World Track and Field Championships suggest that the training period between the ages of 16 and 26 is critical to the development of successful distance runners. The following sections will compare and contrast several common characteristics of successful endurance programs in the sports of biathlon, cross country skiing, and distance running.

PHYSICAL ACTIVITY DURING CHILDHOOD AND EARLY ADOLESCENCE
A large amount of physical activity during childhood (5-12 years of age) and adolescence (age 13 – 19 years) appears to be an important component to the development of an endurance athlete. Conventional wisdom dictates that if sufficient cardiovascular activity is present during periods of growth it may enhance the development of maximum oxygen uptake (VO2). Recent scientific investigations (lngjer, 1992; Saltin, 1995) in cross country skiing and distance running reveal strong anecdotal connections between a large amount of physical activity during childhood and success at the international level in endurance sport.
The relationship between extensive endurance training and VO2 is very strong among cross country skiers. Ingjer (1992) followed seven elite male teenage cross country skiers from Norway over a period of six to nine years from the ages of 13 to 24 years. Two of these athletes became the best senior skiers in the world. Training volume during that period was 10 to 25 hours per week, depending on the time of year. Ingjer found that during the period of rapid pubertal growth (average age 14 – 15 years), 50 per cent of the increase in VO2 max was due to extensive endurance training.
Scandinavian researcher, Bengt Saltin (1995), tested the maximum oxygen uptake of active and less active Kenyan children. Active children from the age of seven years on walked or ran to school at least 8 kilometers per day. The range of habitual activity for the active child was 8-12 km per day. The less active children did not have to travel far to visit neighbors or walk to school.
Active children had VO2 values 30 per cent higher than did the less active children. Saltin also tested 32 junior and senior Kenyan runners, including six Olympic and World Champions. The habitual activity of the junior and senior runners was nearly identical to that of the active children. Saltin concluded that the findings support the notion that Kenyan children have attained their VO2 by being physically active.
Appropriate levels of physical activity for youth is not a new concept. Sport scientist Dietrich Harre from the former East Germany conducted a longitudinal study in children between the ages of nine and twelve (1982). Children were divided into two groups: a multilateral training group and an early specialization training group. The first group participated in a general program, which exposed them to a variety of sports and skills and intensive physical training. The second group began a specific training program devoted exclusively to one sport.
The results demonstrated the effectiveness of multilateral development. Athletes who specialized early had their best performances at 15-16 years of age while those in the multilateral group achieved their top performances at 18 years or older. By 18 years of age, the majority of athletes in the early specialization group had dropped out and those still competing had inconsistent performances. Individuals in the multilateral group had a longer athletic career, fewer injuries, and consistent performances at top -level competition.

AGE OF SPORT SPECIALIZATION
For many years, a strong tradition of success has existed in Australia, Germany, and Sweden in the sports of triathlon, biathlon, and cross country skiing, respectively. Currently, overall rankings from each sport list a number of men and women in the top ten for these three countries. Across these top nations in endurance sport, there exists a common age at which athletes begin to specialize in one sport. Table 3 illustrates the age of sport specialization across three endurance sports in the countries of Australia, Germany, and Sweden. These data suggest a clear trend that the age of sport specialization begins from the mid-to-late teenage years.

LONG-TERM DEVELOPMENT
The most successful endurance training programs in the sports of biathlon, cross country skiing, and distance running take a long-term view of training and competition. A long-term view of training takes into consideration four important points. First, there is a constant attempt to improve performance and the determinants of performance. For endurance sports, the determinants of performance are:
•     Maximum oxygen uptake
•     Power output (e.g., cycling) or velocity (e.g., running) at lactate threshold
•     Economy.

Athletes and coaches focus the training program on these three determinants in an effort to improve performance.
Second, athletes complete a yearly volume of training (endurance and intensity) throughout their career that enables them to see continual improvements in performance. In many cases, the yearly training volume is similar to or greater than the training volume of their competitors.
Third, athletes and coaches who are successful in biathlon and cross country skiing place an emphasis on training over competition. In high school cross country skiing in the United States, athletes have two to three competitions per week over a three-month season (Gibbons, 2000). Due to a demanding competitive schedule and short competitive season, the volume of training is limited. This lack of training reduces long-term development.
In Germany and Sweden for example, two competitive events may occur every two weeks. Therefore, athletes in these countries are able to accumulate large yearly training volumes, which appears to contribute to competitive success.
Finally, long-term programs provide junior athletes with regular exposure to international competition. Providing international competition opportunities at appropriate levels can prepare junior athletes for eventual success at World Championship and Olympic competitions.

TRAINING VOLUME AND INTENSITY DURING ADOLESCENCE AND YOUNG ADULTHOOD
During the developmental ages of 16-24 years, Olympic and World Champions in endurance sport have progressive increases in training volume and large amounts of high intensity training that account for improvement in VO2. Rusko (1992) found that VO2 and relative heart volume increased with age and training from 15 – 20 years old in cross country skiers. Yearly increases in VO2 were one to three milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). At 20 years of age, VO2 began to level off. In skiers who attained a world-class level, VO2 and relative heart volume continued to increase after 20 years of age with concomitant increases in training volume and training intensity.
Ingjer (1992) studied elite male Norwegian skiers ages 13-24 years. Between the ages of 14 and 20 years, VO2 max increased from 3.8 to 5.9 liters of oxygen per minute (L/min). This was the result of increasing training volume from 250 to 750 hours per year (Seiler, 1999). Figure 4 depicts the yearly increases in training volume and VO2 in elite Norwegian cross country skiers.

Training intensity (85-95% of maximum heart rate) was 15 – 25 percent of total volume. Ingjer concluded that extensive endurance training with cyclical variations in volume and intensity was responsible for the improvement in maximal aerobic power in elite Norwegian skiers.
Training volumes for boys and girls training at St. Patrick’s School, a private school in Hen, Kenya, with a highly successful running program, are 80 – 115 km per week during the preparation phase and 50-70 km per week during the competitive season (O’Connell, 1996). This amounts to about 10 – 14 training sessions per week. Fifty to sixty per cent of the training volume is done at or above 90 per cent of VO2 (Saltin, 1995). See Table 4 for training volumes and intensities of Kenyan school children, juniors, and seniors. Kenyan elite seniors age 25 – 27 years report weekly training volumes of 157 km per week.
Kenyan male teenagers (age 16 – 17 years) who were performing regular training had VO2 values of between 65 – 70 ml/kg/min at an altitude of 2000 meters, about 6560 feet above sea level. When tested at sea level, these teenagers had VO2 values above 80 ml/kg/min.
These data from elite cross country skiers and distance runners demonstrate that a large amount of training volume coupled with cyclical variations in training intensity during late adolescence are the primary factors for the continued increase in VO2 values that are necessary to be internationally successful.

HIGH-QUALITY COACHING
High-quality coaching is a primary factor for the improvement of top endurance athletes during the developmental ages of 16-24 years. There are several examples in endurance sport that demonstrate that the foundation for success starts with excellent coaching at these ages. The sport high schools in Germany and Sweden in the sports of biathlon and cross country skiing (Gibbons, 1998b) and distance running programs in Kenya (O’Connell, 1996) have systematically produced Olympic and World Champions. Generally, coaches of these programs have three important principles that are common in their approach to coaching.
•  The design and structure of training is the result of knowledge from sport science and experience.
•  Daily communication between athlete and coach is important in order to adjust the training plan with regard to health status, fitness, and weaknesses.
•  Daily analysis of the training and performance data of each athlete prevents overtraining.

The focus of training in these programs is to provide the requisite training volume and intensity in order to be internationally competitive. One of the challenges to junior athletes age 16 – 19 years when undertaking a year-round training program is how to effectively manage a large training load without accumulating injuries or becoming overtrained. Coaches maximize training and recovery of athletes by providing them with periodized training programs that are guided by current scientific training principles and wisdom from years of experience.
Daily communication between coach and athlete provides the basis for effective training. In the sport high schools located in Germany and Sweden, daily communication between coach and athlete occurs six days a week for 10 months of the year (personal communication with BengtStattin, 1998). During periods of high training volume and intensity, several markers are used to monitor training status. German and Swedish athletes use morning resting heart rate, exercise heart rate, exercise blood lactate, resting blood urea nitrogen, muscle soreness (1- 4 scale), and overall feeling (1-10 scale) to monitor overtraining. Daily discussions with the coach help the athlete understand the relationship between overtraining markers and fatigue. From this information, coaches and athletes recognize short-term or long-term fatigue and adjust training accordingly.

TRAINING PARTNERS AND TEAM ATMOSPHERE
One of the primary goals of European sport high schools is to develop athletes capable of international excellence, and this goal may even appear in the mission statement of the school (Gibbons, 1998b). Admission standards to sport schools are highly competitive and as a result, the pool of athletes entering these schools can be quite talented. Within this environment, talented athletes with similar goals train and compete together, promoting a “critical mass of talent.” The German and Swedish sport schools consistently produce athletes capable of international success, suggesting that the training atmosphere is highly productive for the development of athletes who are focused on international excellence.

APPLICATION TO U.S. DISTANCE RUNNING
We have so far described the common characteristics of successful endurance programs. To recapitulate, these characteristics include:
1. Physical activity during childhood and early adolescence.

2. Age of sport specialization.
3. Long-term development.
4. Training volume and intensity during adolescence and young adulthood.
5. High-quality coaching.
6. Training partners and team atmosphere. We will now discuss the application of these characteristics to U.S.. distance running.

PHYSICAL ACTIVITY DURING CHILDHOOD AND EARLY ADOLESCENCE IN THE U.S.
Several scientific studies indicate that a large amount of habitual activity and regular, cardiovascular training was present in the childhood and adolescent periods of World and Olympic Champions in distance running and cross country skiing. Both Saltin (1995) and Ingjer (1992) found that the increase in VO2, during these periods was due to endurance training. These scientific studies were the first to suggest that the foundation of a large amount of endurance training, larger than previously reported, established during childhood and early adolescence, is a key developmental component of World and Olympic champions in running and cross country skiing.
Further, the research of Harre suggests that early sport specialization (before 14 years old) may be detrimental to the physical and psychological well-being of young athletes. It may be more important for children to receive large amounts of varied physical activity, than structured, organized training early in life. This prompts the following question: Can athletes who enter endurance sport after age 14, without the benefit of a large amount of varied physical activity during childhood, acquire high values of other factors related to endurance performance?
Research on the physical activity of American youth indicates they may have lower amounts of activity compared to children of other countries that are successful in endurance sport. The physical activity of male and female Hershey (Junior Olympics) track athletes, age 9-14 years, was compared against participants in a national survey. As a group, male Hershey track athletes reported more days of moderate activity per week, (3.3 vs. 2.8 days per week with at least 30 minutes of exercise each session) than participants in a nationally representative sample (Ross, 1999).
Female track finalists (9-14 years) reported more moderate and vigorous activity (moderate: 3.4 vs. 2.7 days, vigorous: 4.9 vs. 4.2 days with a least 20 minutes each session) than participants in a national sample. This amounts to a minimum of 3.5 hours of moderate and vigorous activity per week.
This amount is well below that reported by Saltin in Kenyan school children (8-12 km a day). If we calculate 8 km per day for five days a week at a walking pace, it computes to over 8 hours of activity per week. This is similar to the amount of physical activity reported by medal-winning biathletes (5-10 hours per week) from age 8-15 years. This is more than double the amount of weekly physical activity of American track athletes age 9-14 years.

AGE OF SPORT SPECIALIZATION APPLICATION TO U.S. DISTANCE RUNNING
Many of the top distance runners coming out of St. Patrick’s School in Hen, began specializing between the ages of 14-16 years (O’Connell, 1996). These include highly successful athletes such as Sally Barsosio, Mathew Birir, Peter Rono, Rose Cheruiyot, and Wilson Kipketer. Coach Colm O’Connell of St. Patrick’s School comments that, “it is becoming more difficult to break into the successful international scene without having a good basic foundation in the sport.” O’Connell is the first to note that a focus on specialization at age 16 years might inadvertently miss the late-maturing athlete that enters the sport between 18 and 20 years old.

LONG-TERM DEVELOPMENT APPLICATION TO U.S. DISTANCE RUNNING
Are the goals of U.S. scholastic and collegiate track and cross country programs different from the goals of programs that seek long-term development? Two of the most successful U.S. current distance runners, Deena Drossin and Bob Kennedy, have benefited from the course of long-term development. Both runners cite support from coaches who promoted long-term development. In a 1997 Runner’s World interview, Kennedy described his high school program, “Instead of trying to wring everything out me, they let me progress on modest mileage to the next level.” Kennedy’s college coach Sam Bell had him focus on the 1500m first to work on his speed, saving the mileage for later.
Kennedy says, “We were thinking long-term. It’s hard to go back and develop speed as you get older.”
For Drossin, it was post-collegiate coach Joe Vigil who encouraged long-term improvement with a “larger mileage base and better focus” (Personal communication, 1997).

TRAINING VOLUME AND INTENSITY DURING ADOLESCENCE AND YOUNG ADULTHOOD
The current top U.S. distance runners have training volumes that are similar to the top runners in the world. Figure 5 illustrates the training volumes of elite junior and senior Kenyan runners (Saltin, 1995) and American runners, Kennedy and Drossin. These runners completed a training volume during their high school years that was 50-70 per cent of the top Kenyan juniors. Since the age of 18 years, both Kennedy and Drossin have progressively increased their training volume to a level that is similar to top Kenyan seniors as reported by Saltin (1995).

During this period of progressive increments, both Kennedy and Drossin saw dramatic improvements in their 5000m times. From 1989 to 1996, Kennedy improved his 5000m time from 14:21.4 to 12:58.2. Over the last three years, his time has remained between 13:03 and 13:06. From 1992 to 1999, Drossin improved her 5000m time from 16:21.5 to 14:56.8.
Not all athletes will adapt positively to the same training volume. Athletes and coaches need to work together to find the optimum training volume and intensity that will allow an athlete to continually improve. There are many factors that determine endurance performance; however, the performance data of Kennedy and Drossin suggest that their improvements were the result of progressive increases in training volume.

HIGH-QUALITY COACHING
We have outlined three important principles of coaching that are common to successful coaches in Kenya, Germany, and Sweden. These principles are:
• The design and structure of training is the result of knowledge from sport science and experience.
• Daily communication between athlete and coach is important in order to adjust the training plan with regard to health status, fitness, and weaknesses.
• Daily analysis of the training and performance data of each athlete prevents overtraining.

Distance running coach Joe Vigil of Alamosa, Colorado, utilizes all three principles in his successful running program (Personal communication, 1997). To evaluate performance, training status, and recovery Vigil records the following data:
• Morning resting heart rate
• Exercise heart rate
• Recovery heart rate (taken 90 sec. post-exercise)
• Exercise blood lactate.

Overtraining signs:
• Change in body weight

• Change in sleep patterns

• Loss of enthusiasm
• Decrease in performance.

Vigil believes there are many signs that a coach can use to detect overtraining. A coach must be aware of the smallest change in his or her athlete. He talks with the athlete at least once a day and usually several times a day to detect changes. Vigil uses “reference point training” to determine when athletes can advance to more volume or intensity after successfully completing a reference point in training.
For instance, athletes must demonstrate an ability to properly complete distance runs at 85% of race velocity without undue fatigue before advancing to more volume or intensity. In addition, a one-hour class is held every week to educate athletes about current topics in training. Athletes coached by Vigil are educated about training methodology, periodization, technique, and mental training skills. Because of the education and philosophy of the program, Vigil empowers the athlete with the knowledge of what it takes to succeed.

TRAINING PARTNERS AND TEAM ATMOSPHERE
Many fine track coaches in this country know the importance of a healthy and challenging training atmosphere. Creating a training atmosphere with a long-term view of distance running is one of the keys toward systematic development of top U.S. runners.

CONCLUSIONS
Long-term development is a common theme that appears throughout the development of successful endurance athletes. It is an approach to training that seeks appropriate activity during several stages of growth with progressive, sequential training. It appears that a large amount of physical activity starting in childhood and progressing through adulthood with a greater degree of structure and specialization is necessary for international excellence in endurance sport.
There are several studies that document the training histories of World and Olympic Champions in endurance sport. The scientific evidence of Saltin and Ingjer appears to support the anecdotal data of medal winning athletes in running, cross country skiing, and biathlon that the childhood period is filled with participation in a wide variety of sports and a large amount of physical activity. This supports the theory of multilateral development, which states that participation in a variety of sports is essential for developing general coordination and providing sufficient cardiovascular activity to form the foundation for sport-specific training later in life.
A pattern of physical activity that is established during childhood provides an appropriate foundation for a large amount of training to be accomplished during mid-to-late adolescence and young adulthood (aged 16-24 years). It is at this time that most endurance athletes begin specializing in one sport. Data from several researchers support the notion that a large volume of training with cyclical variations in intensity provides the stimulus for continued improvement in VO2 during this period.
To help accomplish this goal, highly educated coaches provide the guidance and support to enable athletes to positively adapt to large training loads without accumulating injuries or overtraining. Daily communication between coach and athlete during late adolescence and young adulthood provides education and guidance for the athlete during years of high training volume and high training intensity.
Currently, two of the best U.S. distance runners, Bob Kennedy and Deena Drossin, share many of these same characteristics in their development. Both runners have benefited from coaches who promote long-term development. Both athletes began running competitively in high school on modest weekly mileage and progressively increased mileage during and after college. Recent training volumes are reported to be between 160-170 km per week during the most extensive training periods. This training volume is similar to top senior Kenyan distance runners. Training volume is one factor that contributes to the success of these runners. In addition, Drossin and Kennedy list training partners as helpful in their development.
The United States currently has over 1.1 million high school athletes in cross country and track & field according to USA Track & Field CEO Craig Masback. The performance trends of the top distance runners in the world demonstrate that progressive, sequential training between the ages of 16-26 years is instrumental to their development. This paper provides evidence that it is the quality of program during late adolescence and young adulthood, not the quantity of participants, that is beneficial in the development of successful endurance athletes.
Historically, the U.S.. has relied on scholastic and collegiate programs to provide training and competitive opportunities for distance runners. This has focused on athletes aged 14-22 years. It appears that reliance on these systems has limited the long-term growth and development of American distance runners. Because of training limitations imposed by high school and college institutions and the rigors of academic life, it may ultimately be more important to provide U.S.. athletes better long-term development during this period than increased training. Further, a four-to-six-year period of progressive, sequential training post-collegiately then becomes a critical period of development.

RECOMMENDATIONS TOWARD LONG-TERM DEVELOPMENT IN U.S. DISTANCE RUNNING
U.S. scholastic and collegiate track and cross country programs can play a larger role in the long-term development of internationally successful distance runners. Changes can be implemented at this level that can dramatically improve the international readiness of American athletes. These changes include:
1. Increase the training volume and intensity.
2. Utilize objective and subjective training markers to monitor training and prevent overtraining.
3. Provide regular education in the areas of training, nutrition, and mental training.

Track and cross country coaches have daily access to athletes aged 14-22 over a nine-month period. This represents an ideal time to implement changes that will promote long-term development.

TRAINING VOLUME AND INTENSITY
Weekly training volume and intensity should be progressively increased to match other international runners of the same age. Bob Kennedy and Deena Drossin had low to modest training volumes in high school, training volumes that were approximately 50-70 per cent of top Kenyan junior boys. Currently, both u.s. runners are matching the training volume of the best international runners.
Every attempt must be made by athletes and coaches to individualize training during high school and college to maximize training. From age 14 to 22 years, progressive increases in training volume and intensity will be accompanied by an improvement in VO2. Additionally, every effort should be made to improve the other determinants of endurance running performance, which include velocity at lactate threshold and economy.

TRAINING MARKERS
The training volumes and intensities of Kenyan runners reported by Saltin require an athlete to tolerate a large training load. The use of training markers may help athletes adapt
positively to large training loads. Utilizing several simple markers will enable the coach and athlete to understand the response to a prescribed training load. Examples of several types of training markers are listed below:
• Morning resting heart rate.
• Exercise heart rate.
• Recovery heart rate.
• Exercise blood lactate.
• Change in body weight.
• Changes in sleep patterns.
• Loss of enthusiasm.
• Decrease in performance
• Muscle soreness (1-4 scale).
• Rating of overall feeling (1-10 scale).

Encourage athletes to use a training log and record several markers on a daily basis. When several of these markers deviate from baselines values and elicit a “red flag” warning, it is time for an adjustment to the training plan.
An analysis of training volume, training intensity, and training markers will help to identify positive and negative training patterns over a monthly or yearly cycle. Training markers have great value to coaches and athletes to understand a training response within an individual athlete. Remember that the best book an athlete can read on training is his or her own training log.

EDUCATION
Regular, weekly education in training, nutrition, and mental training will ultimately benefit the American distance runner by providing him/her with the knowledge and skills to make better decisions and adjustments to the training program. Education sessions can be formal one-hour lectures or a 15-minute session prior to a workout.
Find ways for athletes to implement the information from an educational session into their training program. Delegate more responsibility to the athlete to design and adjust his training plan. The long-term outcome of the educational sessions is to develop an athlete who can independently integrate all aspects of a training program that will promote continual performance improvement.

This will eventually contain all of Alex’s articles

Shoulder Mobility and Health

Chris Korfist Interview

Depth Jump Performance

Anyone who has been around this site for a while knows we have spent a lot of time on the feet. Recently I began thinking about the impacts of improved ankle rocker on running speed. It started with the simple question that is the title of this article.

Why is this a dilemma?

Well, ankle stiffness is the bodies ability to lock the ankle in a position minimizing the eccentric heel dip towards the ground. This heel drop utilizes ankle rocker. So a stiff ankle uses less ankle rocker. The idea being that as the heel dips the tissues deform and leak energy. As the calf eccentrically elongates the force from the hip is not being transferred to the ground it is getting lost in the eccentric contraction.

Well, then why should the athlete or sprinter develop ankle rocker? This question popped into my head when I was watching some videos of Chris Korfist’s sprinters online.

In the video was showing how poor the ankle rocker was. This is because so much time was spent training ankle stiffness. I was thinking “Duh, but who do we need the ankle rocker while sprinting?  I thought we wanted stiffness”

Here is my take:

Athletes need ankle stiffness and a competent ankle rocker despite them seeming to be diametrically opposed.

First upon forefoot strike the athlete utilizes ankle stiffness preventing the heel to dip to the ground and energy leakage. Now once the forefoot is planted and locked the tib/fib rocker over the ankle while the heel is still elevated. Using the ankle rocker allows more horizontal force to be applied to the ground. While we do know much of the force required to maintain a top speed sprint is vertical, during the acceleration phase horizontal force plays a much larger role. By rockering over the ankle you can maintain a better acceleration position and utilize more of the horizontal pulling forces of the glutes and hamstrings. This is very advanced and requires solid coordination. The athlete is using ankle stiffness and ankle rocker simultaneously.

As the athlete rockers over the ankle this requires an eccentric contraction of the gastroc/soleus and a concentric contraction of the dorsiflexors in a specific balance that allows the heel to stay elevated while rockering over the ankle.

So in higher level sprinters ankle stiffness and ankle rocker exists and function simultaneously in a precise and delicate dance between the two opposing functions.

Push-Ups, Face Pulls, and Shrugs

Originally posted at www.t-nation.com

Screw the Rotator Cuff!

That’s right, screw it. Seriously, it’s about as over-hyped as Kevin Federline’s big “debut.” We think the rotator cuff gets way too much attention. Whenever shoulder pain creeps up, what’s the first thing that everyone brings up? The rotator cuff, of course. (Or for those of you from Indiana, that would be your “rotary cup”).

“My shoulder hurts when I bench press.”

“Well, you need to strengthen your rotator cuff.”

“It hurts when I reach overhead or do barbell presses.”

“You’re probably impinging your rotator cuff.”

“I hurt my shoulder pitching and now I can’t collect my million dollar performance bonus.”

“Sounds like you tore your rotator cuff.”

We’ve had it up to our shoulders with the rotator cuff! While the rotator gets all the chicks, all the glamour, and all the attention, the real star of the show is forced to the background. In fact, it never even gets any mirror time at the gym, unless you’re picking at your backne. (We’ve seen you do it).

Allow us to introduce the real star of the show: the scapula!
Our Favorite Bone

The scapula is our favorite bone and we’re not afraid to admit it. (Insert way-too-easy penis joke here.) No other bone in your body functions like the scapula, nor does any have so complex or important a job. Without the scapula, your shoulder is nothing!

When you really examine the scapulae (plural for scapula), one of the first things you’ll notice is that it’s position on the body, and it’s function, are almost entirely determined by the function of the muscles attached to it. If it weren’t for your tiny acromioclavicular (AC) joint and a couple of ligaments, your scapulae wouldn’t have any bony attachments to the rest of the bony skeleton.

Since the scapula is half of the glenohumeral joint (the shoulder joint) and is essentially the foundation of the shoulder, this becomes an important point. Any altered scapular muscle function, weakness, or inability to position the scapula and then stabilize it results in a direct affect on the shoulder joint with dire consequences. These include glenohumeral instability leading to arthritis, impingement, rotator cuff tendonitis/tendinosis, rotator cuff tears, labrum injuries, and so on.

Rather than blindly give you a series of exercises and a program, we think it’s important that you have at least a rudimentary understanding of how the scapula functions.
Functional Anatomy Surrounding the Scapulae

We live in a 3-D world, so the scapulae function in three dimensions. The scapulae tilt forward and backward, rotate inward and outward, and rotate upward and downward.

Through the combined efforts of some 17 muscles it can also protract and retract as well as elevate (shrug) and depress.

Of the typical 180 degrees of overhead reach in a healthy shoulder, the scapulae’s upward rotation is responsible for about 60 degrees of it. It does so through the synergistic efforts of the “upward” rotators: the upper trapezius, the lower trapezius, and serratus anterior.

Now imagine what would happen if you were unable, for whatever reason, to get that necessary movement from the scapulae. What would happen then? In all likelihood, when one (or all) of our scapular upward rotators are weak, inhibited, or simply not able to control and produce movement like they should, impingement syndromes develop and your rotator cuff is at a significantly increased risk of injury.

Contrast this with our downward rotators comprised of the levator scapulae and rhomboids. In her text Diagnosis and Treatment of Movement Impairment Syndromes, Shirley Sahrmann discusses a phenomenon called scapular downward rotation syndrome. In essence, due to poor training, behavioral demands and flat-out poor posture, our scapular downward rotators have a tendency to become short and stiff.

Class, what does all this mean? Let’s use a simple math equation to put the pieces together:

Lack of proper training for the upward rotators + excessive training and postural demands placed on the downward rotators = a recipe for rotator cuff injury!

But as bad as that sounds, it gets worse before it gets better. Let’s delve even further into the matrix, looking at how the majority of us develop our training programs.
Flawed Programming

Flaw #1: Focus on external/internal rotation movements only vs. role as a humeral depression

At the risk of sounding heretical, we’ve got to tell you that all those internal and external rotations aren’t bad, but they’re not doing as much for you as you’d like to think. This is even more true if your only goal is to have a jacked physique or push around heavy iron.

Specific muscles of the rotator cuff do promote certain movements (e.g. the subscapularis promotes internal rotation, the teres minor and infraspinatus promote external rotation, etc.), but there’s a bigger, more functional role that’s very rarely discussed. That role is humeral depression.

Go back to our example of upward rotation — as you move your arm upward, the scapula rotates upward as well. If your rotator cuff is working appropriately, it will exert a downward pull on the humeral head, which keeps it from impinging on the acromion. If the rotator cuff is weak or inhibited, it can’t exert this downward pull, and again we’re left with impingement.

Luckily for you, a lot of the exercises we’ve included focus on the stabilizing role of the rotator cuff. But don’t skip ahead just yet, there’s more to learn!

Flaw #2: Ignoring the effect of the thoracic spine on the scapula and shoulder

The scapula will talk to you if you listen. It will tell you when it’s SICK (yes, there really is a condition called a SICK scapula), it will tell you where you’re strong, and it’ll tell you where you’re weak simply based on its resting position on the ribcage and how it moves, or doesn’t move, when you do.

Because the scapula rests on the ribcage forming the scapulothoracic joint, the shape of the ribcage will also determine the resting position and the mobility of the scapula. In turn, the shape of the ribcage is determined by the postural alignment of the thoracic spine (upper back). This is also why we spend so much time focusing on proper alignment of the thoracic spine in our Inside-Out product line.

This makes your scapula the middleman between the spine and the rotator cuff. We already know that poor scapular mobility or stability can compromise the strength, function, and health of the rotator cuff. Therefore, to assure optimal shoulder function we must develop the relationship from the spine (inside), to the scapula, to the rotator cuff (out).

Let’s look at one example of how the thoracic spine posture affects your shoulder. In a normal thoracic spine/scapular relationship, as you reach upward, the scapula tilts backwards (posterior tilt) to make space in the shoulder joint for the rotator cuff. In a case of thoracic kyphosis (rounded forward upper back), the scapula is unable to tilt backward.

The result is a closing of the gap between the upper arm bone (humerus) and the acromion and impingement of the rotator cuff. In the photos below, you can see how the athlete compensates for an inability to tilt the scapula posteriorly and fully elevate the arms by arching in the lower back. To achieve full elevation, he’s most likely impinging the rotator cuff.

As spine mobility and upper back posture improved (check out the shape of the ribcage), the scapula was free to tilt backward, restore overhead reach, and reduce compensation and impingement.

Day 1	3 months	6 months

Flaw #3: Attempting to balance bench presses with rows

If you read the interview with Bill, you remember that he laid out what the basic movement pattern relationships should be based on the function of the scapulae and rotator cuff. It looks like this:

Abduction/scapular upward rotation to adduction/scapular downward rotation:

• Vertical push to vertical pull

• 0.85-0.95 to 1 (almost 1 to 1)

Protraction to retraction:

• Horizontal push to horizontal pull

• 1 to 1

For the rotator cuff:

• Internal rotation to external rotation

• 1 to 0.75

We all know that we should balance our pushes and pulls, especially with regards to our bench pressing and rowing, right? But what if it’s not so simple a relationship? Do we have your attention?

In essence, what we’re looking at here is balancing our ability to protract and retract the scapulae. Bench pressing is a horizontal pushing movement that you’d think normally produces protraction (forward movement of the scapula around the ribcage) and trains the muscle that cause protraction, a.k.a. the serratus anterior. The logical opposing movement would be a row of some sort. Balanced, right? Wrong.

Question: What’s the most effective scapular position to maximize bench press performance?

Answer: Retraction and depression

Question: What scapular position is achieved in the contracted phase of a rowing movement?

Answer: Retraction and depression

Balanced? Nope.

Get it? What looks good on the outside, feeds an imbalance on the inside. Serratus anterior becomes ineffective as a protractor, stabilizer, and upward rotator. Then there’s an added bonus. But first a quick anatomy lesson.

Next time you’re cutting on a cadaver (What? Doesn’t everyone?), check out the serratus anterior and the rhomboid. What you’ll find is that because of the fascia that covers everything in the body, they’re essentially the same muscle with the scapula kinda stuck in the middle.

So if the serratus anterior isn’t fully effective at producing an upward rotation force and the rhomboid (a downward rotator) is getting trained with both pushes and pulls, then guess who wins the tug-o-war with the scapula.

Correct! The rhomboids and downward rotation. This means you’re more likely to experience shoulder impingement. But that’s not all!

Remember how the thoracic kyphosis limited posterior tilt of the scapula with elevation of your arm? The kyphosis will also promote an anterior tilt of the scapula at rest. Over time, the pec minor (which attaches to the front of the scapula) will stiffen or shorten and the scapula gets “stuck” in an anterior tilt.

This will also result in weakness of the serratus anterior, lower trapezius, and the upper trapezius. These, as you now know, are the upward rotators. Weakness in the upward rotators will then allow the downward rotators to become the dominant force on the scapula. If you need to figure out what happens next, please reread the scapular equation in section two of this article.

So whether you’re a truck driver or a powerlifter, you can end up with the same shoulder dysfunctions.

Truck Driver	Powerlifter

The bottom line? Crappy scapular position leads to crappy scapular stability which leads to crappy rotator cuff function! As Matt Damon’s character in Good Will Hunting would say, “How you like them apples?”

So what’s the fix?
Long Live the Push-Up!

The push-up has been used for centuries to help everyone from cromagnon man to the ancient Greeks, to guys and gals like yourself, with one goal in mind — to achieve a jacked physique! And why not? It’s an amazingly simple exercise that anyone can perform anywhere.

Unfortunately, in recent years, the push-up seems to have fallen out of favor in a lot of circles. For those who like excessively detailed programs, it’s just not “complex” enough. For others, it’s only for the “bodyweight” guys. And lastly, some just don’t know how to fit it into their program and progress it correctly.

Before we get onto the push-up and its progressions, let’s look at some of the research that’s been done regarding push-ups. Obviously, our first goal of performing push-ups is to recruit and strengthen the serratus anterior. So how can we do that?

Lear and Gross determined that push-ups performed with the feet on an elevated surface (in this case the feet were elevated 45.7 cm) significantly increased the activation of the serratus anterior compared to traditional push-up variations. If it’s been a while since you performed traditional push-ups, it would be a good idea to start with basic variations, but elevating the feet is a viable progression if your primary goal is improved serratus function.

Another common question when performing push-ups is, “Where should my hands go?” Cogley et al. wondered this as well, and examined subjects to see how various hand positions affected EMG activity of the pecs and triceps. Researchers looked at three hand positions: shoulder width, hands together, and wide (approximately 90/90 position). The EMG for all trials showed that EMG was highest in the hands together position, which makes perfect sense — this is the position of least mechanical advantage, and therefore more musculature must be recruited to perform the movement.

Adding an unstable surface to the mix can also change which muscles are most heavily recruited. When push-ups were performed with the participant’s hands on a physioball, there was a significant increase in both activation of both the triceps and rectus abdominus. It appears as though the unstable surface increases the activity of the triceps as a shoulder stabilizer, and it also increases the demands of the rectus abdominus to produce stability.

Here’s where things get interesting. It seems the more weight you put on the upper extremity, the higher activation levels you get in the surrounding musculature as well. Uhl et al. examined multiple push-up positions that progressively increased loading on the upper extremity. Researchers started with patients in an all-fours position, and progressively moved them into more loaded positions such as push-up position, push-up position with feet elevated, and even single-arm push-up position.

As you can imagine, the one-arm push-up produced a significant increase in recruitment of shoulder stabilizers such as the supraspinatus, infraspinatus, and posterior deltoid over all the other conditions. It appears as though there are many ways to progressively increase the difficulty and function of the push-up, whether you’re elevating the feet, performing the exercise on an unstable surface, or performing single-arm variants, we’re going to give you a ton of options in the following section.

Hopefully you’re starting to see that whether you’re rehabbing a shoulder injury or just concerned with keeping your shoulders healthy, push-ups are an excellent and undervalued exercise. It should also be stated that just because it’s a great exercise, there’s also a correct way to perform it, and the basic principles of progression should be followed.

In other words, if you’re rehabbing a rotator cuff injury, don’t jump into the most difficult progression right away. As well, if you’re a strong and healthy individual, don’t mess around with the “on-knees” version — get right into something you can do correctly and that challenges you!
Performing the Push-Up

To correctly perform a push-up, lay face down on the floor with your toes pointed, hands and elbows at a 90 degree angle to the shoulders, and stomach tight. Press up to the starting position, making sure to keep the stomach tight throughout, and then lower under control to a point where the chest touches the ground. As you’re lowering, tuck the elbows such that the angle between your upper arm and torso is approximately 45 degrees.

One aspect that we can’t emphasize enough is to use a full range of motion. Be sure to lower under control, and at the top think of pushing your body as far away from the floor as possible. This extra “push” at the end will emphasize proper serratus function.

At this stage in the game, the powerlifters in the group are screaming, “We need more weight!” Trust us, we’re all for progression; we don’t want you using bodyweight resistance for the rest of your life. The easiest progression you can use in this case is a weighted vest such as an Xvest. If you need additional instruction on how to perform push-ups with an Xvest, maybe you shouldn’t be lifting weights at all.
Push-Ups with Bands and Chains

That’s not it though; let’s look at some other ways we can perform the push-up to increase the intensity of the exercise.

Using bands is another option when we want to increase the loading of our push-ups. Again, the progression is simple — once you’ve mastered one band for the desired number of sets and reps, bump it up to the next level. It’s that simple!

To perform push-ups with bands, you’re going to take the band behind your back and place your hands in the ends of the bands such that the band is in the palm of your hand.

As you can see in the picture, you have to make an ëX’ with the band. Simply twist the band, put it behind your back, and you’re ready to rock!

Still not enough variation? You can also drape chains over your back.

If one chain isn’t enough, either move up to the next size of chain or drape multiple chains over your back. The band and chain variations are also excellent for powerlifters looking to improve the lockout of their bench press.

We’ve included two variations of the chain push-up. The first version you cross the chains in a diagonal fashion over your back as in the picture above.

The behind-the-neck version is even tougher; moving the weight further up toward your shoulders will increase the activation of the rotator cuff and make the exercise a lot harder.

Finally, please note that getting the chains on your own back is a pain in the ass. Get a partner to help you out if possible.

Once you’ve mastered the basic push-up variations, feel free to move on to some of the following variations. They’re not only great for strengthening, but they also jack-up the rotator cuff involvement and force your body to stabilize the shoulder in a more dynamic environment.
Med Ball Push-Ups

The medicine ball push-up is a great variation, as it increases activation of the rotator cuff due to the unstable surface. There are multiple variations you can use here.

Start off using a small med ball under one hand, with the other hand pushing off the ground. This will limit the instability to some degree and allow you to learn the exercise. We shouldn’t have to say this, but make sure you’re switching hands either in-between sets or at the midpoint of every set.

If that isn’t enough challenge, move on to the double med-ball version. Place a small med ball under each hand and perform the exercise. As you increase the instability, not only will you recruit more shoulder stabilizing musculature, but you’ll also force your core to increase its stiffness as well. Just try these variations with a soft-tummy; we dare you!
Blast Strap Push-Ups

The blast strap push-up is very similar to the med ball push-up, so we’re not going to continue harping on the topic. Regardless, this is another effective variation you can use.

Enter the Face Pull: The Most Underrated Exercise!

The face pull may be the most underrated exercise in all of strength training. It falls into the horizontal pull category, but where rows potentially promote a downward scapular rotation syndrome and internal rotation of the shoulder joint, the face pull can do just the opposite.

Because the shoulder is either flexed or abducted 90 degrees throughout the face pull, the scapula is in upward rotation to some degree. Right away this gives us greater activation of the upward rotators, especially the upper and lower trapezius. The upward rotation offsets the pull of the downward rotators and helps prevent the development of the downward rotation dominant imbalance.

Now let’s look at face pull performance. Traditionally, the face pull is performed with a rope handle or strap and a pronated grip.

In the contracted position, the pronated grip limits the degree of external rotation of the shoulder.

In thinking about movement pattern balance, we know that the internal rotators of the shoulder tend to be at least 25-33% stronger than the external rotators. We also tend to find that from a postural perspective, internal rotation of the humerus is quite common. Using the traditional pronated grip for the face pull can then potentially feed a rotation imbalance in the shoulder.

To remedy this situation, we recommend the use of a neutral grip. This allows you to pull the rope or strap past your face with the humerus in much greater external rotation and promotes shoulder rotational balance.

To further increase loading the external rotators, the lever arm can be altered by increasing the angle at the elbow. Make sure to adjust the weight accordingly; this is the second version that’s shown in the above video.

Remember those short or stiff pec minors? You can make your face pull more effective by taking advantage of the acute effects of stretching the pec minor for about 20 seconds on each side. You can do this effectively by placing the front of your shoulder against a door jam and leaning your body weight forward and simultaneously pulling the scapula backward.

Diagnosis Via Face Pull

In cases where the rotator cuff is known to be weak relative to the deltoid, the posterior deltoid can overtake the rotator cuff as the primary external rotator.

This will show up in the face pull as the humerus (upper arm bone) hyperabducts relative to the scapula. In other words, as you pull horizontally, the scapula stops moving and the upper arm bone continues to be pulled back along the horizontal plane. Rather than the upper arm bone and the scapula ending up in the same plane during the contracted phase of the face pull, the upper arm bone and scapula form an angle. The dead giveaway is a dent or a dimple that forms between the posterior deltoid and the infraspinatus.

If this is the case, your shoulder program would be better served by working on some isolated strengthening to the rotator.
The Only Shrugs You Haven’t Done Before!

One of the common findings in a downwardly rotated scapula is a lengthened upper trapezius. In this situation, the excessive length makes the upper trap weak and a less than effective upward rotator of the scapula. Ineffective upward rotation of the scapula, especially with overhead movements, is a recipe for rotator cuff injury.

The obvious fix would be to address the weakness with some form of shrugging movement to strengthen the upper trapezius and improve the upward rotation function. There’s just one catch: the typical barbell or dumbbell shrug may make the situation worse.

A shrug with the arms at the sides will certainly activate the upper trapezius, however it also strongly recruits the levator scapulae and the rhomboids, the downward scapular rotators. This feeds the imbalance causing the downward scapular rotation dominance.

The answer is to perform a shrugging movement with the scapulae in an upwardly rotated position with the overhead shrug.

Now if you have or have had shoulder problems resulting in pain, the overhead shrug may be problematic. In this case, the next best exercise is scaption with a shrug.

Scaption is essentially a thumb-side up, dumbbell lateral raise in the plane of the scapula. The plane of the scapula is about 30 degrees or so in front of a lateral raise performed straight out to the side of the body.

Summary

Proper training and injury prevention go hand in hand. You can’t have one without the other.

As you can see, we’ve presented one scenario where dysfunction, and potential injury, may exist that can’t be “fixed” with a few sets of external rotations for the rotator cuff. A lack of attention to proper daily postures and less than optimal exercise selection can, given enough time, be a recipe for rotator cuff injury and lost training time or worse.

So what does it take to assure a healthy rotator cuff? If we had to boil it all down to three principles it would be this:

1. Maintain adequate mobility and posture of the upper back to allow for adequate mobility of the scapulae.

2. Maintain optimal balance of the muscles around the scapulae and the shoulder joint.

3. Proper exercise selection with compound movements can correct and maintain those optimal relationships that not only improve performance but also prevent injury.

Sometimes an isolation exercise like external rotations may be an answer, but that’s an article for another time.

I found the following study very interesting. It was sent to me by colleague Cal Dietz I think the first sentence of the abstract sums it up best.  I have thought for a long time that one key to improving performance on the field is training the body to act like a spring.

Teaching the muscles and connective tissues to absorb and release force in a spring like manner. This study looks at the tendon spring and it’s effects at buffering forces that are eccentrically absorbed by the muscles.

Enjoy

-Alel

The series-elastic shock absorber: tendons attenuate muscle power during eccentric actions Thomas J. Roberts1,* and Emanuel A. Azizi1

1Brown University

Submitted 10 November 2009 ; revised 24 May 2010 ; accepted in final form

25 May 2010

Elastic tendons can act as muscle power amplifiers or energy-conserving springs during locomotion. We used an in situ muscle-tendon preparation to examine the mechanical function of tendons during lengthening contractions, when muscles absorb energy. Force, length and power were measured in the lateral gastrocnemius muscle of wild turkeys. Sonomicrometry was used to measure muscle fascicle length independently from muscle-tendon unit (MTU) length as measured by a muscle ergometer. A series of ramp stretches of varying velocities was applied to the MTU in fully activated muscles.

Fascicle length changes were decoupled from length changes imposed on the MTU by the ergometor. Under most conditions, muscle fascicles shortened on average while the MTU lengthened. Energy input to the MTU during the fastest lengthenings was -54.4 J kg-1, while estimated work input to the muscle fascicles during this period was only -11.24 J kg-1. This discrepancy indicates that energy was first absorbed by elastic elements, then released to do work on muscle fascicles during the post-lengthening period of the contraction. The temporary storage of energy by elastic elements also resulted in a significant attenuation of power input to the muscle fascicles. At the fastest lengthening rates, peak instantaneous power input to the MTU reached -2,143.9 W kg-1, while peak power input to the fascicles was only -557.6 W kg-1. These results demonstrate that tendons may act as mechanical buffers by limiting peak muscle forces, lengthening rates, and power inputs during energy-absorbing contractions.

tendon; eccentric; muscle; muscle damage