[MF1]Are these values comparing S to NS or Pre to Post?
[MF1]Are these values comparing S to NS or Pre to Post?
PERFORMANCE CHANGES IN NBA BASKETBALL PLAYERS VARY IN STARTERS VS. NON-STARTERS OVER A COMPETITIVE SEASON
Adam M. Gonzalez, Jay R. Hoffman, Joseph P. Rogowski, William Burgos, Edward Manalo, Keon Weise, Maren S. Fragala, and Jeffrey R. Stout
Human Performance Laboratory, University of Central Florida, Orlando, FL
The NBA professional basketball season imposes a great amount of physiological stress and demand which may subject athletes to overtraining syndrome. Tracking sport specific performance characteristics in starters (S) with more high-level playing time over a competitive season may allow players and coaches to identify performance changes indicative of overtraining.
PURPOSE: To compare starters (S) to non-starters (NS), on their ability to maintain strength, power and quickness during a competitive NBA season.
METHODS: 12 NBA players were assessed at the beginning of the competitive season. The seven (S = 4, NS = 3) players (28.2 ± 3.4 y; 200.9 ± 9.4 cm; 104.7 ± 13.9 kg; 7.2 ± 1.9 % body fat) who remained injury free and avoided a trade were also assessed at the end of the season and underwent analysis. Anthropometric, performance (repetitive vertical jump power [VJP], squat power [SQT power], and reaction time) and subjective feelings of energy, focus, alertness, and fatigue were recorded during each testing session. Results were interpreted using magnitude-based statistics to make inferences on true differences between S and NS using the unequal variances t-statistic.
RESULTS: S played an average of 27.8 ± 6.9 min·game-1 and NS played an average of 11.3 ± 7.0 min·game-1. During the course of the season, changes in VJP indicated that S were likely to increase VJP (∆ = 77.3 ± 78.1 W) compared to NS (∆ = -160.0 ± 151.0 W). There also appeared to be a possible beneficial effect on maintaining reaction time in S (∆ = 0.005 ± 0.074 s) compared to NS (∆ = 0.047 ± 0.073 s). In addition, no clear difference in Δ SQT power were seen between S (∆ = 110.8 ± 141.4 W) and NS (∆ = 143.5 ± 24.7 W). Changes in subjective feelings of energy indicated that S were very likely to maintain their energy over the course of a season. It also appeared possible that S were able to have a more positive response to subjective measures of fatigue and alertness than NS, with only trivial differences between S and NS in regards to maintaining focus.
CONCLUSIONS: Results of this study suggest that NBA players may enhance lower body power, repetitive jump ability and reaction during a competitive season, which appears to be enhanced with the stimulus of playing time.
Table 1. Individual player Δ scores in Vertical Jump Power from beginning to end of season.
- Starters (n = 4) played an average of 1813 ± 639 total game-time minutes (27.8 ± 6.9 min·game-1) and NS (n = 3) played an average of 543 ± 375 total minutes (11.3 ± 7.0 min·game-1) over the competitive season.
- Evaluation of magnitude inferences indicated:
- Possible that S maintained their body mass (0.5 ± 1.2 kg), while NS lost body mass (-0.9 ± 3.1 kg).
- Change in body composition indicated a possible beneficial effect of S (0.025 ± 1.389 %) on maintaining BF% compared to NS (0.833 ± 1.443 %).
- Changes in vertical jump power indicated that S was likely to increase (77.3 ± 78.1 W) compared to NS (-160.0 ± 151.0 W).
- Possible beneficial effect on maintaining reaction time in S (0.005 ± 0.074 s) compared to NS (0.047 ± 0.073 s).
- There appeared to be no clear difference in Δ SQT power between S (110.8 ± 141.4 W) and NS (143.5 ± 24.7 W). Interestingly, all players (both S and NS) increased SQT power during the course of the basketball season.
- Seven players under contract to play for the NBA franchise Orlando Magic (28.2±3.4 y; 200.9±9.4 cm height; 104.7±13.9 kg weight; 7.2±1.9 body fat %) were assessed at the beginning and end of the competitive season.
- All athletes performed anthropometric (height, body mass and body composition), repetitive vertical jump power, squat power, quickness and reaction time assessments. In addition, during each testing session, subjective feelings of energy, focus, alertness, and fatigue were recorded.
- The effects of the NBA season were calculated as the change from pre-season to post-season measurements among Starters and Non-starters.
Table 1. Pre to Post Season Changes in Subjective Measures of Energy, Fatigue, Focus and Alertness.
Figure 1. Magnitude Based Inferences on Anthropometric and Performance Changes during a Season of Competition in NBA Starters versus Non-starters
SUMMARY & CONCLUSIONS
- To our knowledge, this is the first study attempting to quantify the magnitude of performance changes during an NBA basketball season.
- The results of this study indicated that S were not only able to maintain their physical performance levels throughout the season, but the greater playing time appeared to have provided a greater stimulus for enhancing vertical jump power.
- In addition, S appeared to maintain their body composition and reaction time better than NS.
- Greater playing time also appeared to have positive effects on feelings of fatigue and alertness.
- The only detriment associated with S was a possible decrease in energy as the season progressed.
- There is limited research published pertaining to the NBA’s athletes and their demanding season.
- Assessing sport specific performance characteristics of professional basketball players during the season may provide coaches and training staffs an ability to identify and make necessary adjustments to reduce the risk for overtraining.
- Research has clearly indicated that basketball is predominantly an anaerobic sport (Hoffman et al., 2003, Ostojic et al., 2006); therefore an appropriate battery of physiological assessments must include sport specific anaerobic tests.
- Several studies have indicated that performance measures can be maintained during a season of competition (Hoffman, Maresh et al., 1991; Hoffman et al., 2000), while others have indicated that gains in strength can be achieved in previously untrained basketball players during a competitive season (Hoffman, Fry et al., 1991). However, none of these studies examined a season that was of similar length to that seen of an NBA team.
- Statistical Analysis
- Magnitude based inferential analysis was used as an alternative to normal parametric statistics to account for the small sample size (n = 7).
- The precision of the magnitude inference was set at 90% confidence limits, using a p-value derived from an unpaired t-test and the threshold values remained constant at ± 0.2 for the small sample size.
- Inferences on true differences between starters and non-starters were determined using the unequal variances t-statistic on a published spreadsheet (Batterham, 2005).
- It was very unlikely that S maintained feelings of energy in comparison to NS over the course of a season.
- It was possible that S were able to have a more positive response to subjective measures of fatigue and alertness than NS.
- There appeared to be trivial differences between S and NS in regards to the ability to maintain focus.
- The importance of monitoring elite basketball players’ performance for overtraining is crucial not only to the athletes, but also the success of teams. However, it is important to acknowledge that each athlete responds individually to the stresses of practice and games. Although the results of the team may be consistent, it is important for the strength and conditioning coach to examine individual player performance as well. When needed specific adjustments to the athlete’s daily routine (i.e. greater recovery, less time on the court) may prevent potential performance decrements that may not manifest as part of the team results. Results of this study suggest that NBA players may enhance lower body power, repetitive jump ability, and reaction during a competitive season. This appears to be enhanced with the stimulus of competition.
Figure 2.Magnitude Based Inferences on Changes in Subjective Measures of Energy, Focus, Fatigue, and Alertness during a Season of Competition in NBA Starters versus Non-starters
To examine pre- to end of season performance changes in a professional NBA basketball team.
To compare starters (player in the regular rotation) to non-starters (players not in the regular rotation) on the ability to maintain strength, power, and quickness during a competitive NBA season.