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Original Research

Online Video–Based Resistance Training Improves the Physical Capacity of Junior Basketball Athletes

Klusemann, Markus J.; Pyne, David B.; Fay, Tristan S.; Drinkwater, Eric J.

Author Information
Journal of Strength and Conditioning Research: October 2012 - Volume 26 - Issue 10 - p 2677-2684
doi: 10.1519/JSC.0b013e318241b021
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Abstract

Introduction

The physical abilities of junior basketball athletes can influence the level of competition they reach (12,16). A well-developed physique is associated with an increased court time (17) and basketball-specific fitness measures (8). Increasing the physical capacity through resistance training for junior athletes improves musculoskeletal characteristics, reduces injury risk, and enhances motor performance (13). The long-term development of junior basketball players should focus on increasing their physical abilities throughout a conditioning program, incorporating resistance training (5,13).

Resistance training forms an integral part of developing the physical abilities of high-level basketball players (33). An 18-month basketball training program can improve aerobic fitness levels and reduce percentage body fat; however, substantial gains in muscle strength or joint mobility are difficult to achieve from basketball training alone (37). Several research studies have demonstrated that supervised short-term resistance training programs with junior athletes can elicit substantial gains in strength and performance measures in basketball (6,7,24,31), soccer (26,40), tennis (3), rugby (10,34), and handball (15). A supervised 10-week complex training (resistance plus plyometric training) intervention elicited significant improvements in upper-body and lower-body explosiveness in adolescent basketball players (31). These increases in fitness were also significantly greater than a control group that only completed basketball training. These findings support the need for effective short-term resistance training programs to improve strength and physical performance in junior basketball athletes.

Improvements in physical abilities are often small in magnitude and require a considerable investment of time and resources (20,29). For example, 2 years of training were necessary to achieve small substantial gains in vertical jump height in national female basketball athletes, whereas national male athletes failed to improve vertical jump height over the same period (11). Access to gym equipment is limited, can be impractical, and should not be used by novice athletes without expert supervision (13). To enhance the progression of fitness and conditioning in junior athletes, the issue of how to implement well-designed resistance training programs to athletes at an earlier stage in their development must be addressed.

The lack of a well-designed supervised training program for junior athletes may be overcome with the use of an online video–based resistance training program. A media-based intervention that outlines general and specific details of the exercises and lifting techniques in the absence of a specialist strength and conditioning coach may be an effective option. Whether an online video–based resistance training program is effective in comparison with supervised or no strength training is unclear. The aim of this study was to compare the magnitude of improvement (change) in strength, functional movement patterns, and physical performance of junior basketball athletes after 6 weeks of resistance training, employing either a fully supervised or an online video–based instruction program.

Methods

Experimental Approach to the Problem

A longitudinal, controlled, experimental trial was conducted to quantify the effects of a fully supervised and an instructional online video–based resistance training program on strength, functional movement patterns, and physical performance measures in junior basketball players. Two experimental groups (supervised and video) underwent double baseline testing, followed by a 6-week training period, and finally posttesting in-season (February–March). A third control group completed the testing but did not receive any resistance training during the study period.

Subjects

Thirty-nine (males, n = 17; age, 14 ± 1 years; height, 1.79 ± 0.10 m; mass, 67 ± 12 kg; females, n = 22; age, 15 ± 1 years; height, 1.70 ± 0.07 m; mass 62 ± 8 kg) adolescent basketball players were recruited for the study. All subjects were part of a state squad in their age group or part of a state-level development program or both and undertaking a minimum of 3 basketball training sessions plus 1 game a week. None of the athletes had prior experience in resistance exercise, and all were classified as beginners in strength training. The subjects were allocated into the supervised (SG; n = 13), video (VG; n = 13), or control (CG; n = 13) group with the aim of minimizing differences in group means of age, gender, and strength scores achieved at baseline testing (18). Subjects needed to complete a minimum of 75% of the training sessions to be included in the final data analysis. Written informed consent was obtained from all participants and their parents or guardians. The research project was approved by the Australian Institute of Sport (20101207) and Charles Sturt University (2011/013) Ethics Committees.

Procedures

Testing

Subjects were tested twice in 2 weeks before the 6-week training period, and posttesting occurred in the week after training was completed. Each testing phase was divided into 2 testing sessions on different days. The first session involved a battery of basketball-specific physical tests, whereas the second session comprised functional movement screening (FMS), and power and strength testing. All subjects were encouraged to come to testing well rested (no heavy exertion 24 hours prior), hydrated, and at least 2 hours after a light snack or meal.

Subjects underwent basketball-specific physical testing on Monday or Tuesday morning at 7 AM before school commitments. Performance measures of physical ability, which included speed (20-m sprint), vertical jump height, agility, and anaerobic (line drill test) and aerobic capacity (Yo-Yo intermittent recovery level 1 test [Yo-Yo IRL1]), were conducted under standardized conditions (36). Most athletes had performed these tests previously, and hence minimal learning effects were assumed. Subjects performed a 15-minute standardized warm-up protocol before being tested.

Functional movement screening, countermovement jump height (CMJ), and strength were assessed 5 days later. Functional movement patterns were evaluated using 7 screening tests (overhead squat, hurdle step, in-line lunge, shoulder mobility, straight leg raise, push-up, and rotary stability), as outlined by Kiesel et al. (21) and Minick et al. (25). In addition, a landing screen was included to assess landing technique. The FMS was used to evaluate changes in functional movement competency. Subjects conducted 2 trials of each movement, and the best movement pattern was scored. The movement patterns were rated by a certified strength and conditioning specialist according to a 4-point scale (0–3), and screens involving a right/left side component were rated with the lower of the 2 scores. The individual FMS scores were summated to compute a total score (FMS Sum8). All participants conducted 3 clearance screens before FMS (25). All trials were filmed from the frontal and sagittal planes to allow repeated scoring of the FMS. Test-retest reliability for the FMS was evaluated by 8 experts from the strength and conditioning and physiotherapy fields. Ten subjects were randomly selected and scored twice by each expert with at least 1 month between scoring.

Countermovement jump height was measured to assess the capabilities of the lower extremity in the long stretch-shortening cycle. Countermovement jump testing was conducted on a force plate fitted with a linear position transducer using Ballistic Measurement System software (Fitness Technology, Inc., South Australia, Australia). Subjects performed 2 sets of 3 maximal CMJs with a 3-minute rest interval between sets. Jumps were performed with an aluminum pole held to the upper part of the back at the base of the neck (trapezius muscle), which was attached to the position transducer and eliminated any arm swing. Warm-up consisted of 2 sets of 5 jumps at 70% and 90% of maximum effort, respectively. Subjects were instructed to stand “still and straight” at the beginning of data collection and then to jump as “fast and high” as possible. No hip, knee, or ankle flexion was allowed during the flight phase to ensure valid trials. The best jump height from both sets of CMJs was used for analysis.

Strength was measured using a 15-second push-up and modified pull-up test, as outlined by Negrete et al. (27). Push-ups were counted using a push button device, which released an auditory signal when pressed by the subject's chest. The device had a height of 6.5 cm and ensured all subjects reached the same depth for all push-ups. The push-up test was performed in the standard position (23): hands positioned slightly wider than shoulder width apart with the trunk held in a rigid straight position with support on the toes. Subjects who were unable to perform one correct repetition during the warm-up assumed a modified push-up position with support on their knees. The number of push-ups completed that produced audio signals in the 15-second bout was recorded.

The modified pull-up was performed on a Smith machine with a bench positioned under the subject's feet. Subjects assumed a supine position with their heels on the bench and held on to a bar with a pronated grip. The bar was positioned in line with the shoulders, just above arms' reach when the subject lay supine on the floor. Subjects were instructed to lift their hips to form a straight body with their arms still fully extended and maintain this rigid trunk posture throughout the test. Full range of motion was enforced by ensuring that the subject achieved an elbow flexion of at least 90° (upper arms are parallel to the floor). The number of successful repetitions within the 15-second period was recorded. Only 1 maximum effort trial was conducted with these tests to avoid fatigue effects in this subject group. Using 3 maximal trials for each test, Negrete et al. (27) calculated intraclass correlation coefficients for the push-up and modified pull-up test of 0.958 and 0.989, respectively.

Training Program

The SG trained twice a week for approximately 1 hour with 2 rest days in between the sessions. Subjects from the SG trained in the early mornings on Monday and Thursday or Tuesday and Friday. Subjects from the VG could choose their own training times but were advised to keep the same training days and maintain a 2-day recovery period. The training program was designed by the principal researcher using a strength and conditioning software package (Visualcoaching Pro 2.0.2.0; VisualCoaching Pty, Ltd, Melbourne, Australia) and was the same for both the training groups. The training program was planned so that all exercises could be conducted on a basketball court. Hence, all exercises incorporated the use of body weight resistance and available objects and equipment, such as a chair, towel, and basketballs. The training program incorporated the following exercise elements: landing technique, agility/change of direction, jumping technique, squatting technique, lunge technique, push-ups, towel pull-ups, dips, and trunk/stability exercises. Training progression over the 6-week intervention was ensured through an increase in volume with more repetitions or a small modification of the exercise to increase intensity or both.

Supervised training involved small group sessions with a maximum of 6 participants and a minimum of 2 experienced strength and conditioning coaches, ensuring a 3:1 athlete-to-coach ratio. Subjects received verbal, visual, and kinesthetic feedback on proper exercise technique and were given strong verbal encouragement to complete the prescribed number of sets and repetitions.

Online video–based training required the subjects to log in to a Web site where the training programs were presented. A new training program was uploaded each week to ensure the subjects followed the planned progression of exercises. The exercises were described in full detail with tips and cautions, as well as a video clip demonstrating the correct execution of the exercise. Subjects had the option of printing out the program and instructions or to access the information via a mobile device to refer to during training. All subjects were asked to complete an online training diary to assess compliance to the training program.

Statistical Analyses

To avoid the shortcomings of research based in null hypothesis significance testing, magnitude-based inferences, and precision of estimation were employed (4). Performance measures were log transformed before the analysis to reduce the nonuniformity of error. The best result achieved in the double baseline testing was used as the criterion baseline measure. Magnitude-based inferences on the differences in the mean (pre to post) changes between the 3 treatment groups were determined. Qualitative descriptors of standardized effects were assessed using these criteria: trivial, <0.2; small, 0.2–0.6; moderate, 0.6–1.2; large, 1.2–2.0; and very large, >2.0 (19). Precision of estimates is indicated with 90% confidence limits, which defines the range representing the uncertainty in the true value of the (unknown) population mean. Effects with confidence limits overlapping the thresholds for small positive and negative effects (exceeding 0.2 of the SD on both sides of the null) were defined as unclear. Clear small or larger effect sizes were defined as substantial. Test-retest reliability was calculated from the typical error of measurement and intraclass correlation coefficient.

Results

One control subject was unable to complete the posttesting because of a basketball-related injury and was excluded from the analysis. Training logs from the online diary revealed 96% compliance from the supervised group and 77% compliance from the video group. In the supervised group, 3 subjects missed 1 session and 1 subject missed 3 sessions because of illness. The training logs did not reveal all causes for the lower compliance in the video group. Only 5 subjects from the video group completed all 12 sessions, whereas 2 subjects were excluded from the final analysis for low compliance (<75%). Illness was anecdotally reported in some cases. Final data analysis included a total number of 36 subjects (SG, n = 13; VG, n = 11; CG, n = 12).

Physical Testing Results

Substantial changes in physical performance can be seen for all groups (Table 1). The control group's performance deteriorated or remained similar to baseline in all physical tests except for the agility test (−1.5 ± 1.6%, mean ± 90% confidence limits; small, qualitative inference). The supervised and video groups made small improvements in vertical jump height (5.4 ± 2.4% and 4.3 ± 2.7%, respectively) and agility (−2.2 ± 2.2% and −3.8 ± 1.1%). The supervised group additionally had a small increase in Yo-Yo IRL1 scores (35 ± 28%; small). Trivial or unclear changes occurred in 20-m sprint time (−0.5 ± 1.0% and −1.6 ± 2.0%) and line drill performance (0.5 ± 2.1% and −0.9 ± 1.4%) for the supervised and video groups. Sit and reach distance remained trivial for the supervised group (−1.2 ± 1.1%) but declined for the video group (−1.6 ± 1.7%) and control group (−1.9 ± 1.3%). Differences between the supervised and video groups were trivial or unclear in vertical jump, sit and reach, and 20-m sprint performance. The video group had greater improvements in agility (−1.7 ± 2.4%; small) and line drill (−1.4 ± 2.5%; small) performance than the supervised group. The supervised group showed better Yo-Yo IRL1 performance (−18 ± 31%; small) than the video group.

Table 1
Table 1:
Physical testing results for the supervised group (SG), video group (VG), and control group (CG) including %change of the pre-post mean and %difference of the mean changes between the groups (sit and reach is in raw units).*

Strength Test Results

There was a substantial increase in the CMJ in the supervised group (5.0 ± 4.2%; small) and a substantial decrease in the control group (−4.6 ± 6.2%; small). The change in the video group was unclear. The supervised group had a substantially larger mean change in CMJ height than the control group (−9.2 ± 7.3%; moderate) but with little difference compared with the video group (−4.2 ± 8.0%; unclear).

Both the supervised and video groups had small increases in the number of push-ups performed (20 ± 13% and 23 ± 15%). The control group had a substantial decrease in push-ups (−13 ± 17%; small). Although the experimental groups had substantial differences in the mean changes to the control group, differences between the supervised and video groups in push-up strength were unclear (Table 2). No clear changes were found in the pull-up test for the supervised group (1 ± 13%) and video group (1 ± 21%); however, the control group had a trivial decrease in pull-up strength (−6 ± 18%). Supervised training almost certainly improved FMS scores, and moderate-to-large differences were evident between the supervised group and the video and control groups (Table 2). The typical error for FMS intratest reliability was 4.5% with an intraclass correlation coefficient of 0.82.

Table 2
Table 2:
Countermovement jump height (CMJ), strength test, and functional movement screen results of the supervised group (SG), video group (VG), and control group (CG).

Discussion

The analysis of the experimental controlled trial revealed substantial improvements in several measures of physical performance for the experimental groups after a 6-week resistance training intervention. Both short-term supervised and online video–based resistance training were effective in improving physical performance measures and strength. The supervised group made superior gains in endurance (Yo-Yo IRL1), whereas the video group had larger improvements in acceleration and change of direction tasks (agility, line drill). A larger resistance training volume (and possibly cumulative fatigue) in the supervised group may have impaired their ability to achieve superior gains in acceleration tasks compared with the video group. Because endurance and cardiovascular adaptations were not targeted specifically in the training program, the increase in Yo-Yo IRL1 performance by both the experimental groups is presumably related to improvements in movement efficiency. These findings demonstrate the effectiveness of short-term resistance training programs for improving physical performance in adolescent basketball athletes (6,7,31). Although previous research has focused on off-season training programs, the results from our study show that positive gains can also be achieved in-season with junior basketball athletes (31). Enhancements in our physical performance measures (20-m sprint, step in vertical jump, Yo-Yo IRL1) also indicate the usefulness of resistance training for improving the sport-specific locomotor performance of basketball athletes.

Substantial gains in strength and speed-strength were also identified in both experimental groups. Lower extremity speed-strength in the long stretch-shortening cycle (CMJ) improved substantially by 5% in the supervised group. Short-term improvements in vertical jump ability are most likely because of enhanced intermuscular and intramuscular coordination (30). Jumping and landing technique was emphasized at the start of the training sessions, and verbal feedback was given regarding jumping technique in the supervised group. The increase in vertical jump height likely reflects both neuromuscular adaptations and improved technique. Both the supervised and video groups had substantial improvements in the number of push-ups achieved in the 15-second push-up test. Push-ups were a main component of the training program and had high conformity with the test protocol, thus allowing maximal transfer of strength adaptations to the performance measure. This was not the case with pull-up strength. Neither of the experimental groups had clear gains in the 15-second pull-up test. Because of the constraints of the training environment (basketball court), no supine pull-up exercise could be included in the training program. Instead, a vertical towel pull-up exercise was used to train the posterior upper-body musculature. Although an increase in repetitions was achieved during training in this exercise, these strength gains did not appear to transfer to the supine pull-up test. A vertical pull-up test was not used because of the lack of strength in this adolescent athlete population.

Functional movement patterns form the basis of physical performance and skill technique (9). Poor functional movement patterns are associated with decreased fitness (22) and increased injury risk (21), although these findings remain to be confirmed in other groups (28,35). Poor landing technique has been associated with anterior cruciate ligament injuries (1) but can be improved with plyometric and strength training (2). Supervised training, which provides verbal and kinesthetic feedback to the athlete, can enhance motor learning and therefore have a greater impact on modifying movement patterns. Supervised training was the only training format that improved FMS scores in our study. This finding supports the need for expert supervision to enhance movement patterns and that this benefit is less likely in unsupervised exercise programs. Functional movement screening intrarater reliability has previously shown to be good (14,25,32,35). Our evaluation of FMS intratester reliability suggests that noncertified experts in strength and conditioning or physiotherapy can reliably score functional movement screens.

This is the first study to demonstrate positive effects of an online video–based resistance training program in junior athletes. Similar online physical activity interventions have been applied to an adult population and yielded benefits on physical activity (38,39). Unsupervised strength training programs for adolescent rugby athletes without media interaction have shown positive benefits, although these have been mostly smaller in magnitude when compared with supervised training (10,34). The resistance training program used in this research project was solely conducted on the basketball court. The evidence that this type of program can induce positive adaptations in strength and physical performance has an important practical application. Gym facilities with adequate resistance training equipment and expert supervision are often limited and less accessible for junior athletes. A court-based resistance training program offers an effective solution and has been previously shown to improve physical performance in adolescent basketball athletes (6).

The outcomes of this study need to be interpreted within the following limitations. To standardize the workload, the resistance training program was equal for all subjects. Maturation and gender effects may therefore explain the large degree of variation in some of our performance measures. The procedure for conducting functional movement screens was limited to the information available in the literature (21,25). Certification in FMS could possibly increase the scoring precision and intrarater reliability. The training intervention used in this study was of a short 6-week period. Whether an online video–based resistance training program yields more substantial benefits over a longer period remains unclear. Further longitudinal research is required to evaluate whether Internet-based interventions are effective in senior basketball players and other sports.

In summary, an online video–based resistance training program is a viable option to improve the physical capacity of junior basketball athletes. Supervised training and expert program design is necessary to provide feedback on correct movement patterns, lifting techniques, and progression of exercises.

Practical Applications

Supervised training remains the best method of program delivery to achieve maximum compliance, test performance, and individualized feedback. In circumstances where supervised training is not available, online video–based training could be used to elicit substantial improvements in physical performance and strength in junior basketball athletes. This form of media-based training is a cost-effective and practical solution to apply resistance training to a large or a remote athlete group or both. Sporting bodies could use this strategy to educate coaches and athletes on how to implement resistance training exercises into their daily training environment and enhance the short-term physical development of junior athletes. A combination of supervised and online video–based training may offer larger benefits than online video–based training alone.

Acknowledgments

The authors acknowledge the support of Brendan Parnell from Basketball ACT (Australian Capital Territory) Academy of Sport for his assistance in recruiting subjects for this project. Luke Howie (VisualCoaching Pty, Ltd) also assisted greatly through provision and technical support of the Visual Coaching Pro software. Andrew Govus, Sean Verwey, and Lachlan Mitchell of the Department of Physiology, Australian Institute of Sport, assisted in data collection. They also thank the colleagues who assisted in providing data for the reliability of the FMS. Funding was provided by the Australian Institute of Sport, Basketball Australia and Charles Sturt University.

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Keywords:

strength training; Internet-based intervention; functional movement screen; unsupervised training

Copyright © 2012 by the National Strength & Conditioning Association.