Regular participation in physical education (PE) helps school-age youth to develop healthy habits and provides an opportunity for children and adolescents to take responsibility for their own health (1,15). In the short term, PE can improve the fitness of youth, relieve stress, and enhance academic performance (15,24). In the long-term, PE can enhance the overall health of individuals and contribute to a lifetime of physical activity (15,20). However, many states, districts, and schools allow students to be exempt from participating in PE for a variety of reasons including participation in school sports (12). Despite the noteworthy differences between PE and school sports (15), about 25% of highs schools allow young athletes to be exempt from PE requirements (12).
Although some observers suggest that participation in moderate to vigorous physical activity during after-school school sports can replace PE, another prevalent concern among some young athletes and youth coaches is that PE on the same day as sports practice or competition may have adverse consequences on performance because of the lingering effects of fatigue. Hence, some young athletes are exempt or discouraged from actively participating in PE during their sport season and miss a unique opportunity to obtain the knowledge and skills needed to maintain an active lifestyle into adulthood. Although interscholastic sport programs are important, a primary goal of PE is to help students gain competence and confidence in their abilities to lead physically active lives by participating regularly in age-appropriate activities that enhance both health- and skill-related components of physical fitness (15).
In adult populations, moderate and heavy resistance exercise has been shown to result in acute neuromuscular fatigue in both resistance trained (7,17) and untrained (8,13) men and women. Because neuromuscular fatigue can reduce the force-producing capability of the muscle, such fatigue could influence performance if it is performed before sports practice or competition. However, the intensity of the training session, training volume, and time course of recovery need to be considered. For example, in another study, it was found that a 1-hour bout of moderate intensity resistance training (RT) had no immediate effect on motor performance tests in untrained women (11) and others reported that vertical jump, anaerobic power, and shooting accuracy were not altered 6 hours after RT in collegiate women basketball players (25). Indeed, some coaches incorporate RT into precompetition activities, and it is not uncommon for adult athletes to work out on the day of a competition (26,28).
Although few data exist on the effects of an acute bout of physical exertion on fitness performance in younger populations, Fry et al. reported that a low-volume, moderate intensity training session performed 5-6 hours before competition enhanced performance in junior weightlifters who exhibited high levels of perceived anxiety (6). Conversely, Oliver et al. found significant reductions in jumping performance in adolescent soccer players when jumping drills were performed immediately after 42 minutes of soccer-specific exercise (16). Because different types of exercise loading require different durations of recovery, the observed differences in performance in the aforementioned reports are likely because of the nature and intensity of the exercise loading and the length of the recovery period.
Despite these interesting observations, no investigation has directly examined after-school fitness performance following different PE lessons in young athletes. Most studies quantifying the effects of human muscle fatigue on performance have used trained and untrained adults, and no studies have used exercise protocols that are consistent with current PE recommendations for children and adolescents. Because of growth- and maturation-related differences in response to physical exertion (5,19) and the observation that fatigue induced from strenuous RT or weightlifting may be different from that produced from less-intense intermittent activities (2), further research is warranted to evaluate the effects of school-based PE on after-school fitness performance. This information could have important implications for young athletes, youth coaches, and PE teachers.
Therefore, the purpose of the present investigation was to determine the acute effects of PE lessons consisting of aerobic exercise (AE), RT, or sport-skill practice on after-school fitness performance in young athletes. Although a myriad of PE classes and conditioning activities could have been used for this study, we used moderate intensity PE lessons that were consistent with national standards and guidelines (1). Furthermore, because data are needed to gain insights into the potential effects of school-based PE on after-school fitness performance, we purposefully used a series of skill-based motor performance tests to assess fitness performance. We hypothesized that school-based PE lessons would not have an adverse effect on after-school fitness performance in adolescent athletes.
Experimental Approach to the Problem
In this study, we wanted to compare the acute effects of different PE lessons on after-school fitness performance in adolescent athletes. A group of young athletes participated in 3 different PE lessons in random order on nonconsecutive days. The 3 lessons were consistent with national PE guide lines and consisted of intermittent AE, RT, or skill-based basketball training. After-school following each PE lesson and on a control day without PE, subjects performed a series of fitness tests designed to measure power, speed, muscle endurance, and flexibility. All subjects were evaluated by PE teachers and members of the research team who had experience teaching and testing youth. This design allowed us to individually assess after-school fitness performance and carefully monitor the response of each subject to study procedures.
Nine girls and 11 boys volunteered to take part in this study. No subject withdrew because of injury or other adverse experiences. The mean ± SD for age, height, and body mass of the subjects was 15.2 ± 0.8 years, 168.9 ± 9.6 cm, and 66.5 ± 18.7 kg, respectively. All subjects were multisport athletes who participated in a variety of sports including American football, soccer, basketball, baseball, softball, field hockey, gymnastics, and swimming. The methods and procedures used in this study were approved by the Institutional Review Board for use of human subjects at the College, and informed consent was obtained from all subjects and their parents.
Subjects participated in 3 different PE lessons on nonconsecutive days as part of their regularly scheduled PE class. All subjects had prior experience performing all activities that were performed during each PE lesson. Subjects also participated in a control day without PE. The order of the PE lessons was randomized among subjects. Each PE lesson was 43 minutes in duration, and the same PE teacher taught every class. All PE activities took place between 10:30 am and 2 pm, and subjects were asked not to participate in any other moderate to vigorous physical activity (outside of PE class) on a testing day. Also, subjects in this study were cognizant of the effects of nutrition on performance and were asked to maintain healthy food choices and adequate hydration throughout the study period. Because of differences in grade level and other academic requirements, it was not possible for all subjects to participate in PE at the same time of day.
All classes began with a 5-minute warm-up of low-intensity AE and calisthenics and ended with 5 minutes of cooldown activities including static stretching. A description of each PE lesson is noted below.
- (a) Aerobic training. Subjects participated in a jog/walk class on a 400-m synthetic outdoor track. An audible signal was used to sustain intervals of 6 minutes of jogging followed by 2 minutes of walking. Subjects were instructed to maintain a jogging pace that elicited a heart rate of 140-160 b·min−1. Heart rates were measured with portable heart rate monitors (Polar Electro Inc., Waterbury, NY, USA).
- (b) Resistance training. Subjects participated in an RT class which included 2 weightlifting exercises (3 sets of 3-6 repetitions using 30-40% of back squat weight on the push press and clean pull exercises), 4 strength exercises (3 sets of 10-15 repetitions with a progressive load on the bench press, seated row, shoulder press, and upright row exercises), 2 abdominal and 2 lower back strengthening exercises (2 sets of 10-15 repetitions with a 1-kg medicine ball), and 3 dumbbell exercises for the shoulder musculature (2 sets of 12-15 repetitions with 2-4 kg).
- (c) Basketball skill training (BS). Subjects participated in a basketball skill class and practiced 3 previously mastered basketball skills including lay-ups and multiposition jump shots. After these activities, subjects participated in a 15-minute half court basketball game using learned game strategies and tactics.
The height and body mass of each subject was measured following standard procedures. Power, speed, and agility were evaluated using the vertical jump, standing long jump, proagility shuttle run, seated medicine ball toss, 20-m sprint, and 200-m sprint tests. Standardized protocols for fitness testing were followed according to methods previously described (10,21). Subjects were familiar with these fitness tests from participation in PE classes and after-school sport programs.
The vertical jump was measured using the Vertec Jump Training System (Sports Imports, Hilliard, OH, USA). The Vertec has 49 color-coded, moveable vanes that are spaced 1.27 cm apart. Subjects were instructed to jump as high as possible and touch the highest vane. The vertical jump was calculated by subtracting a subject's standing reach height from his or her maximal jump height. The standing long jump was measured on a mat that was fixed to the floor. Subjects were permitted to perform a countermovement before jumping vertically or horizontally. Lower back and hamstring flexibilities were evaluated by the sit and reach flexibility test. The seated medicine ball toss was performed with a 4-kg medicine ball (about the size of a shot put). The participants sat on the floor with their back against a wall and were instructed to toss the ball as far as they could with both hands at an approximate angle of 45° (similar to a chest pass). The best jump of 3 trials for the vertical jump and long jump and best performance of 3 trials for the flexibility test and seated medicine ball toss was recorded to the nearest 1.0 cm.
The electronic Speed Trap II Timing System (Brower Timing Systems, Draper, UT, USA) was used to time the 20-m sprint, 200-m sprint, and proagility shuttle run. For the proagility shuttle run, the subjects started on a centerline facing the researcher. The subjects sprinted 4.55 m to the left, then 9.1 m to the right, and finally 4.55 m back to finish as they crossed the centerline. The best time of 2 trials for the proagility shuttle run and 20-m sprint was recorded to the nearest 0.01 seconds. The time from 1 trial for the 200-m sprint was recorded to the nearest 0.01 seconds. Scores resulting from improper technique or incorrect body positioning during any fitness test were discarded. Test-retest reliability intraclass Rs for all the dependent variables was R ≥ 0.85.
To facilitate testing procedures, subjects were tested in groups of 3-5 by the same 2 researchers. Fitness testing began after-school at 3:30 pm to provide a recovery period of at least 1.5 hour from PE. After a 5-minute warm-up period of low-intensity AE and calisthenics, subjects performed the fitness tests in the same test order (i.e., flexibility, long jump, vertical jump, 20-m sprint, proagility shuttle run, and 200-m sprint). All testing occurred in a high school gymnasium or on a synthetic outdoor track in April, which was the off-season for most subjects. All subjects completed the fitness test battery in about 45 minutes. Testing procedures used in this study were designed to be similar to fitness testing procedures used in most PE and youth sport programs. Each subject completed all study procedures within 10 days.
Descriptive statistics (mean ± SD) for age, height, body mass, and fitness variables were calculated. Analysis of variance was used to analyze differences between criterion measures after the PE classes and control day. Because no significant differences were observed between genders, data were pooled. Statistical significance was set at p ≤ 0.05, and all analyses were carried out using the Statistical Package for the Social Sciences version 10.0 (SPSS, Inc. Chicago, IL).
There were no significant differences in flexibility, vertical jump, long jump, seated medicine ball toss, proagility shuttle run, 20-m sprint, and 200-m sprint after the AE, RT, BS, or the control day. Data for all fitness variables after all testing sessions are in Table 1.
A common belief among some young athletes and high school coaches is that participation in PE or other physical activities will have an adverse effect on after-school fitness performance. In this investigation, we provide evidence that participation in PE consisting of AE, RT, or BS has no significant effect on after-school fitness performance in adolescent athletes. Because regular participation in PE can contribute to the physical, mental, and social well-being of youth (15), these findings suggest that adolescent athletes can participate in developmentally appropriate PE classes on the same day as after-school fitness conditioning providing that the overall volume and intensity of the PE class is moderate and consistent with individual abilities and the recovery period is adequate. To our knowledge, no other study has examined the effects of different PE lessons on after-school fitness performance in adolescent athletes. Of note, our results should not be generalized to after-school sports practice or competition, which typically involve higher levels of physical and psychological stress.
Previous studies involving adults have suggested that the intensity and volume of the exercise session and the duration of the recovery period are important considerations when evaluating the effects of fitness training or sport conditioning on fitness tests performed later in the day (7,9,11,25). For example, Häkkinen et al. reported significant reductions in performance after moderate and heavy resistance exercise in trained and untrained adults (7-9). In one of these reports, reductions in strength and neural activity were noted after a morning workout in elite adult athletes who performed a relatively intense and voluminous training session (9). Kauranen et al. reported that a bout of moderate-intensity circuit weight training decreased muscle strength immediately post exercise in untrained women although no significant effect on motor performance skills were observed (11). Others found that RT had no immediate effect on basketball free throw shooting accuracy in collegiate basketball players (23).
Although neuromuscular fatigue resulting from an exercise bout can influence force-generating capability of muscle, these data suggest that the magnitude of this effect is dependent, at least in part, on the intensity of the exercise and the duration of the recovery period. For example, high-intensity exercise has been shown to elicit a dramatic acute endocrine response in adults, but these responses return to normal within 6 hours after the exercise session (14). In the present investigation, we did not expect participation in PE to have an adverse effect on after-school fitness performance because the intensity of each PE class was moderate and the recovery time between PE and the fitness tests was adequate. We intentionally used a moderate intensity for all PE classes so subjects could be involved and active for the majority of the class time while enjoying each lesson. These practices are consistent with national standards and guidelines for PE (1). Of note, all subjects in our study were athletes who participated in sports training and conditioning activities (both aerobic and RT) under the supervision of their coach.
Few data are available on the time course of fatigue after a bout of physical exertion in adults, and data on youth are scarce. Raastad et al. observed that adult athletes were able to recover force and squat jump performance in 3 hours after a moderate RT protocol but required 33 hours to recover from a heavy RT protocol (17). Others noted that vertical jump, anaerobic power and shooting accuracy were not altered 6 hours after moderate-intensity RT in women basketball players (25). Although it has been shown that youth recovery faster than adults from a short bout of high-intensity anaerobic exercise (27), immediate recovery from an intense bout of exercise should be distinguished from training recovery between exercise sessions. Although the purpose of the present investigation was not to assess the time course of recovery, all subjects in our study had 1.5-4.25 hours (mean 2.8 ± 1.1 hours) to recover from PE before they performed the fitness tests. During this recovery time, they engaged in classroom activities that were sedentary in nature.
Our findings indicate that power, speed, muscle endurance, and flexibility are unaffected by participating in PE provided that the exercise intensity is moderate, the overall volume is reasonable, and the recovery period is adequate. Although a pre-event protocol of moderate and high intensity exercise has been shown to create an optimal environment for power production in adolescents (3,4), in these investigations, performance was assessed within 5 minutes of the pre-event protocol. Because this effect is unlikely to be maintained several hours after a moderate-intensity PE class (22), changes in after-school fitness performance were not expected.
In our study, subjects completed a series of fitness tests within 45 minutes. Admittedly, the intensity and duration of this test battery was less than most high-school sport practice sessions and competitions. In many cases, sports practice and competition may last for several hours and involve intermittent bouts of low-, moderate-, and high-intensity physical effort along with elevated levels of pretraining or precompetition state anxiety. In addition, subjects in our study participated in 1 moderate intensity PE lesson each day and had between 1.5 and 4.25 hours to recover from each lesson. Consequently, the results from our investigation may not be consistent with the demands of all PE lessons or after-school activities that may be characterized by more intense or voluminous bouts of physical exertion or by more frequent training sessions (e.g., 2 workouts in 1 day).
In addition, our findings may only apply to adolescents who are physically fit and regularly participate in sports training and conditioning. Because others observed that the decrement in sports performance in adolescent soccer players was significantly correlated to their physical fitness (18), it should be noted that subjects in our investigation were young athletes who regularly participated in sports training and conditioning activities. Future study on this topic might manipulate PE lesson variables (e.g., intensity, volume, and mode) and the timing of the recovery period. A more in-depth analysis of the physiological and psychological effects of PE on after-school sports competition in different types of young athletes (e.g., cross country runners and weightlifters) is also needed.
The results of our investigation indicate that participation in a developmentally appropriate PE lesson that consists of AE, RT, or BS will not have an adverse effect on after-school fitness performance in adolescent athletes. Because the objectives of a comprehensive PE program extend beyond improving physical fitness and include helping students understand and value physical fitness and the benefits of a healthy lifestyle (15), young athletes should not be discouraged from participating in a well-designed PE lesson on the day of after-school fitness conditioning provided that adequate recovery is available. Although future studies are needed to evaluate the effects of PE on after-school sports performance, our findings are important for youth coaches and PE teachers who want to enhance the physical fitness of young athletes while providing them with an opportunity to gain the skills and knowledge they need for a lifetime of physical activity.
The authors gratefully acknowledge the administration and faculty at Hillsborough High School, Hillsborough, NJ, for their support of this research study.
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