William E. Amonette

Endurance training and cardiorespiratory conditioning after traumatic brain injury

ObjectiveTo examine the importance of cardiorespiratory conditioning after traumatic brain injury (TBI) and provide recommendations for patients recovering from TBI. MethodReview of literature assessing the effectiveness of endurance training programs. Main outcomes and resultsA sedentary lifestyle and lack of endurance are common characteristics of individuals with TBI who have a reduction in peak aerobic capacity of 25% to 30% compared with healthy sedentary persons. Increased physical activity and exercise training improves cardiorespiratory fitness in many populations with physical and cognitive impairments. Therefore, increasing the endurance and cardiorespiratory fitness of persons with TBI would seem to have important health implications. However, review of the TBI literature reveals that there have been few well-designed, well-controlled studies of physiologic and psychological adaptations of fitness training. Also lacking are long-term follow-up studies of persons with TBI. ConclusionsAssessing endurance capacity and cardiorespiratory fitness early in the TBI rehabilitation process merits consideration as a standard of care by professional rehabilitation societies. Also, providing effective, safe, and accessible training modalities would seem to be an important consideration for persons with TBI, given the mobility impairments many possess. Long-term follow-up studies are needed to assess the effectiveness of cardiorespiratory training programs on overall morbidity and mortality.

Nullius in verba: a call for the incorporation of evidence-based practice into the discipline of exercise science.

Evidence-based practice (EBP) is a concept that was popularized in the early 1990s by several physicians who recognized that medical practice should be based on the best and most current available evidence. Although this concept seems self-evident, much of medical practice was based on outdated textbooks and oral tradition passed down in medical school. Currently, exercise science is in a similar situation. Due to a lack of regulation within the exercise community, the discipline of exercise science is particularly prone to bias and misinformation, as evidenced by the plethora of available programmes with efficacy supported by anecdote alone. In this review, we provide a description of the five steps in EBP: (i) develop a question; (ii) find evidence; (iii) evaluate the evidence; (iv) incorporate evidence into practice; and (v) re-evaluate the evidence. Although objections have been raised to the EBP process, we believe that its incorporation into exercise science will improve the credibility of our discipline and will keep exercise practitioners and academics on the cutting edge of the most current research findings.

Ventilatory anaerobic thresholds of individuals recovering from traumatic brain injury compared with noninjured controls

Objective:The purpose of this study was to compare the peak aerobic capacities and ventilatory anaerobic thresholds (VAT) of individuals with a traumatic brain injury (TBI) to age- and gender-matched controls. Methods:Nineteen participants that previously suffered a mild to moderate TBI and 19 apparently healthy controls volunteered as subjects. Traumatic brain injury and healthy controls were matched for age and gender and were similar in weight and body mass index. Volunteers performed a maximal graded treadmill test to volitional failure where oxygen consumption (O2), carbon dioxide production (CO2, ventilation (E, and heart rate were measured continuously. From metabolic and ventilatory data, VAT was measured using a previously described method. VAT and peak exercise responses of participants with a TBI were compared with healthy controls. Results:The O2, and CO2 at VAT and peak exercise were lower for TBI compared with healthy controls. E was also lower for TBI at VAT and peak exercise. Heart rate was lower for TBI at VAT; however, TBI had similar heart rate to healthy controls at peak exercise. Conclusions:The VAT and peak exercise capacities of participants with a TBI were below the metabolic demands of many routine daily activities. The data suggest that therapeutic interventions for individuals with a TBI should include targeted exercise prescriptions to improve cardiorespiratory fitness.

PEAK VERTICAL JUMP POWER ESTIMATIONS IN YOUTHS AND YOUNG ADULTS

Abstract Amonette, WE, Brown, LE, De Witt, JK, Dupler, TL, Tran, TT, Tufano, JJ, and Spiering, BA. Peak vertical jump power estimations in youths and young adults. J Strength Cond Res 26(7): 1749–1755, 2012—The purpose of this study was to develop and validate a regression equation to estimate peak power (PP) using a large sample of athletic youths and young adults. Anthropometric and vertical jump ground reaction forces were collected from 460 male volunteers (age: 12–24 years). Of these 460 volunteers, a stratified random sample of 45 subjects representing 3 different age groups (12–15 years [n = 15], 16–18 years [n = 15], and 19–24 years [n = 15]) was selected as a validation sample. Data from the remaining 415 subjects were used to develop a new equation (“Novel”) to estimate PP using age, body mass (BM), and vertical jump height (VJH) via backward stepwise regression. Independently, age (r = 0.57), BM (r = 0.83), and VJ (r = 0.65) were significantly (p < 0.05) correlated with PP. However, age did not significantly (p = 0.53) contribute to the final prediction equation (Novel): PP (watts) = 63.6 × VJH (centimeters) + 42.7 × BM (kilograms) − 1,846.5 (r = 0.96; standard error of the estimate= 250.7 W). For each age group, there were no differences between actual PP (overall group mean ± SD: 3,244 ± 991 W) and PP estimated using Novel (3,253 ± 1,037 W). Conversely, other previously published equations produced PP estimates that were significantly different than actual PP. The large sample size used in this study (n = 415) likely explains the greater accuracy of the reported Novel equation compared with previously developed equations (n = 17–161). Although this Novel equation can accurately estimate PP values for a group of subjects, between-subject comparisons estimating PP using Novel or any other previously published equations should be interpreted with caution because of large intersubject error (± >600 W) associated with predictions.

What is “Evidence-Based” Strength and Conditioning?

SUMMARY THE TERM “EVIDENCE-BASED” HAS BEGUN APPEARING IN THE FIELD OF STRENGTH AND CONDITIONING. HOWEVER, THIS TERM HAS YET TO BE FORMALLY INTRODUCED TO THE STRENGTH AND CONDITIONING COMMUNITY. FAR FROM BEING A MERE BUZZWORD, EVIDENCE-BASED PRACTICE (EBP) IS A DEFINED PROCESS BY WHICH PRACTITIONERS (IN THIS INSTANCE, STRENGTH AND CONDITIONING PROFESSIONALS) INCORPORATE THE “BEST” AVAILABLE EVIDENCE INTO THE EVERYDAY TRAINING OF ATHLETES AND CLIENTS. INCORPORATION OF EBP INTO THE STRENGTH AND CONDITIONING FIELD WILL IMPROVE THE QUALITY OF TRAINING PROGRAMS PROVIDED FOR ATHLETES AND CLIENTS AND INCREASE THE PRESTIGE AND STANDING OF OUR DISCIPLINE.

Physical Determinants of Interval Sprint Times in Youth Soccer Players

Abstract Relationships between sprinting speed, body mass, and vertical jump kinetics were assessed in 243 male soccer athletes ranging from 10-19 years. Participants ran a maximal 36.6 meter sprint; times at 9.1 (10 y) and 36.6 m (40 y) were determined using an electronic timing system. Body mass was measured by means of an electronic scale and body composition using a 3-site skinfold measurement completed by a skilled technician. Countermovement vertical jumps were performed on a force platform - from this test peak force was measured and peak power and vertical jump height were calculated. It was determined that age (r=-0.59; p<0.01), body mass (r=-0.52; p<0.01), lean mass (r=-0.61; p<0.01), vertical jump height (r=-0.67; p<0.01), peak power (r=-0.64; p<0.01), and peak force (r=-0.56; p<0.01) were correlated with time at 9.1 meters. Time-to-complete a 36.6 meter sprint was correlated with age (r=-0.71; p<0.01), body mass (r=- 0.67; p<0.01), lean mass (r=-0.76; p<0.01), vertical jump height (r=-0.75; p<0.01), peak power (r=-0.78; p<0.01), and peak force (r=-0.69; p<0.01). These data indicate that soccer coaches desiring to improve speed in their athletes should devote substantive time to fitness programs that increase lean body mass and vertical force as well as power generating capabilities of their athletes. Additionally, vertical jump testing, with or without a force platform, may be a useful tool to screen soccer athletes for speed potential.

Sprint Accelerations to First Base Among Major League Baseball Players With Different Years of Career Experience.

Abstract Coleman, AE and Amonette, WE. Sprint accelerations to first base among Major League Baseball players with different years of career experience. J Strength Cond Res 29(7): 1759–1765, 2015—The purpose of this article was to compare times to first base in Major League Baseball games to determine whether running velocity decreases to the foul line and first base among players with differing years of playing experience. From 1998 to 2012, 1,185 sprint times to first base were analyzed: 469 outfielders, 601 infielders, and 115 catchers. The players were divided into differing experience categories depending on their years of service in Major League Baseball: 1–5, 6–10, 11–15, and 16–20+ years. Velocity at the foul line and first base was compared and interval accelerations were reported. Comparisons were completed by playing position, and within left- and right-handed batters. Left-handed outfielders exhibited reduced velocities at 6–10 (p = 0.04), 11–15 (p = 0.004), and 16–20 years (p < 0.001) compared with 1–5 years; there were no statistical differences in velocity at the foul line. Right-handed outfielders exhibited significantly reduced velocities at first base in 6–10 (p = 0.002) and 11–15 years (p = 0.001); they also had a reduced velocities at the foul line in 6–10 (p = 0.004) and 11–15 years (p = 0.009). Right-handed infielders had reduced velocities at first base in 11–15 years (p < 0.001). No other differences were observed within infielders at first base or the foul line. There were no differences within the compared variables for catchers. Decreases in running velocity to first base with experience are seen in outfielders but are less prominent in infielders and catchers. Although physical capabilities for sprinting may decline with age, it is possible that through repetition more experienced players perfect the skill-related component of running to first base, thus preserving speed.

Pure Acceleration Is the Primary Determinant of Speed to First-Base in Major-League Baseball Game Situations

Abstract Coleman, AE and Amonette, WE. Pure acceleration is the primary determinant of speed to first-base in major-league baseball game situations. J Strength Cond Res 26(6): 1455–1460, 2012—The purposes of this research were to (a) quantify interval sprint times between Home-Plate and the Foul-Line and the Foul-Line and First-Base, (b) determine if differences exist in interval velocities and acceleration between left- and right-handed batters or between-position groupings, and (c) to quantify determinants of time to First-Base in Major-League Baseball players during actual games. A total of 1,896 sprint times to the Foul-Line (13.7 m) and First-Base (27.4 m) were recorded in 302 baseball players by a single coach, positioned in the dugout with a hand-held stopwatch. Interval velocities and accelerations were computed between Home-Plate and the Foul-Line and the Foul-Line and First-Base; average velocity and acceleration were also determined over the entire 27.4 m. Velocity and acceleration for left-handed batters were greater than for right-handed batters from Home-Plate to the Foul-Line and from Home-Plate to First-Base; however, there were no differences in velocity or acceleration from the Foul-Line to First-Base. Interval velocity was significantly greater for outfielders and infielders compared with that for catchers from Home-Plate to the Foul-Line and from the Home-Plate to First-Base. Outfielders were faster than catchers from the Foul-Line to First-Base; no other between-group differences were evident. Accelerations from Home-Plate to the Foul-Line and from Home-Plate to First-Base were greater for outfielders compared with infielders and catchers. Infielders accelerated at greater rates than did catchers between these intervals. There were no between-position differences in acceleration from the Foul-Line to First-Base. These data indicate that time to First-Base is most affected by acceleration from Home-Plate to the Foul-Line. Coaches should implement strategies that encourage players to sprint maximally over the first 13.7 m to maximize chances of successfully reaching First-Base.

Physical Determinants of Velocity and Agility in High School Football Players: Differences Between Position Groups

PURPOSE: The purpose of this study was to develop prediction equations for speed and agility within different position groupings of High School football players using age, height, body mass, and vertical jump as predictor variables. METHODS: A total of 987 athletes (14-18y) completed testing at a regional high school football combine. Athletes were divided into three groups according to their playing position: Linemen (LM; n = 354; 16.3 6 0.8y; 179.4 6 5.6cm; 105.1 6 18.3kg), Big Skill Players (BSP; n = 189; 16.2 6 0.9y; 175.5cm 6 5.2cm; 85.7 6 11.6kg), and Skill Players (SP; n = 444; 16.4 6 09y; 175.8 6 5.9cm; 75.5 6 8.9kg). The LM included offensive tackles, offensive guards, centers, defensive tackles, and defensive ends. BSP included linebackers, running backs, and tight ends. SP included wide receivers, corner backs, safeties, and quarterbacks. In sequential order, height (HT), body mass (BM), 40 yard sprint (40Y), 5-10-5 shuttle (SH), and countermovement vertical jump height (VJ) were determined on each player. HT and BM were measured using a stadiometer and an electronic scale, respectively. 40Y and SH were measured using hand-held stop watches; the highest of two trials was used for analysis. Two vertical jumps were completed on an electronic pressure mat; vertical jump height was calculated using flight time. For each position grouping, correlations (Pearson’s r) were calculated between the four predictor variables