Neuromuscular Performance: The Countermovement Jump and Its Relationship to Sleep, Skill, Recovery, and Psychological Factors in Male Collegiate Basketball Athletes
Curtis, Michael, Education - School of Education and Human Development, University of Virginia
Hertel, Jay, ED-KINE, University of Virginia
Neuromuscular performance (NMP) can be regarded as the ability of the neuromuscular system to functionally control and drive movements by an appropriate integration, coordination and use of sensory feedback, reflex activity, central motor drive, muscle recruitment pattern, muscular excitation-contraction coupling and energy substrate availability. More simply stated, neuromuscular performance relates to the synergistic relationship between coordination and force application. It is associated with underpinning biomotor abilities (e.g., sprinting, jumping, and change of direction) necessary for sport participation. The ability to measure and monitor NMP may provide medical and performance-related professionals the ability to glean greater understanding regarding the readiness of athletes as they navigate the training process and competitions. The countermovement jump (CMJ) has emerged as a valid and reliable monitoring tool in applied and laboratory settings with extensive research investing the utility of the CMJ in field and court-based sports like soccer, rugby, and basketball specifically. Despite the wealth of evidence investigating the CMJ and its dose-response to training constructs like external load and disparate methodological training protocols, there is a paucity of literature investigating other ecological factors surrounding participation in sport and their relationships to neuromuscular readiness. The purpose of this dissertation was to investigate the effects of sleep, recovery modality, and psychological stress on NMP in division I male basketball student-athletes. The purpose of manuscript 1 was to evaluate the effects of sleep duration on NMP performance and shooting accuracy in a shooting task constructed by a sport coach specific to the technical and tactical demands of collegiate division I basketball during the preseason. We did this using an observational prospective cross-sectional design using best and worst night sleep weekly to evaluate differences in select CMJ variables, shot percentage, and wellness while controlling for accelerometry derived external training load. We found that there were significant differences in best and worst night sleep in our study cohort. However, we did not observe significant differences in CMJ variables, Jump Height (JH) and Flight Time:Contraction Time (FT:CT) as well as shooting accuracy, or wellness measures across the 3 weeks of the preseason. The purpose of manuscript 2 was to evaluate the effects of recovery modality on NMP during the early competitive season in collegiate basketball. We used an observational prospective, randomized block-controlled design to evaluate the differential effects of flotation-restricted environmental stimulus therapy (Floatation-REST), peristaltic compression therapy (PPDC), and a control treatment on select CMJ variables and wellness measures 16-20 hours post recovery treatment during 3 weeks of the early inseason in collegiate basketball players. Our results showed no statistically significant differences in CMJ variables JH, FT:CT and countermovement depth (CMD) pre to post across recovery interventions. Additionally, we observed no significant differences in wellness measured via the Short Recovery Stress Scale (SRSS) between Floatation-REST, PPDC, or Control treatments. The purpose of manuscript 3 was to evaluate the effects of psychological stress on NMP during the competitive season in collegiate basketball. We used an observational prospective, repeated measures design to investigate the effects of psychological stress measured via the CCAPS-34 to detect domain specific (e.g., depression, general anxiety, social anxiety, academic stress, eating concerns, frustration/anger, and alcohol use) over the course of the late in-season in collegiate basketball. Our resulted showed that there were statistically significant reductions in neuromuscular performance during the season. We observed statistically significant decreases in JH and Modified Reactive Strength Index (RSI-Mod) across the late inseason. Our investigation revealed that differences in CCAPS-34 subscales across the study did not rise to the level of significance, however, we did see trends that suggest the CCAPS-34 instrument is sensitive to period of increased academic demand. Contextually, our data revealed that significant reductions in NMP did correspond with non-significant, yet meaningful increases in academic stress, game congestion, and increased travel. Interesting, our secondary analysis comparing PlayStatus did not reveal differences in NMP or CCAPS-34 measures. In undertaking these studies, the challenges of in-situ research were demonstrated. Small sample sizes in isolated team settings challenge the use of inferential statistical models. There is a need to for collaboration across multiple teams to construct larger datasets for analysis. Despite these statistical obstacles we were able to observe trends that may elucidate practically significant findings that may aid practitioners who a required to make informed decisions based on observations in NMP and interactions with sleep, recovery modalities, and psychological factors in real world settings.
PHD (Doctor of Philosophy)
Neuromuscular Performance, Countermovement Jump, Sleep, Psychological Stress, Recovery, Basketball