Relationship Between Range of Motion, Strength, Motor Control, Power, and the Tennis Serve in Competitive-Level Tennis Players: A Pilot Study.

BACKGROUND: The tennis serve is a complex skill requiring appropriate energy transfer to maximize serve speed. As the only independently powered shot in tennis, it is important to understand what characteristics contribute to a player's serve. HYPOTHESIS: Upper extremity and lower extremity power variables will be predictive of serve speed. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 42 competitive tennis players underwent range of motion, strength, motor control, power, and serve speed testing. Motion assessment was completed for shoulder external and internal rotation, trunk rotation, hip external and internal rotation, and ankle dorsiflexion. Strength was assessed for the rotator cuff, scapula, and hip musculature. Motor control was evaluated through upper and lower extremity Y-balance testing. Power assessments were made using broad jump, single-leg hop, and seated unilateral shot put testing. Pearson correlation was conducted to assess associations of skill, height, and tested variables to serve speed. Significant variables were used in a stepwise linear regression model, with serve speed as the dependent variable. Variables are listed in relation to the participant's dominant arm. RESULTS: Skill, height, contralateral hip external rotation range of motion, nondominant arm Y-balance anterolateral reach, bilateral single-leg hops, and seated unilateral shot put throws for both arms demonstrated significant positive correlations to serve speed ( P < 0.05). Serve speed was predicted with 84% variance through skill, height, contralateral hip external rotation range of motion, ipsilateral single-leg hop, and the seated unilateral shot put throws. CONCLUSION: The ability to generate increased serve speed is multifactorial. The combination of skill, height, hip motion, and upper and lower extremity power may determine serve speed. CLINICAL RELEVANCE: The findings suggest that motion, motor control, and power testing should be evaluated when working with this population to improve serve speed.

Concussion May Increase the Risk of Subsequent Lower Extremity Musculoskeletal Injury in Collegiate Athletes.

BACKGROUND: Laboratory-based studies on neuromuscular control after concussion and epidemiological studies suggest that concussion may increase the risk of subsequent musculoskeletal injury. OBJECTIVE: The purpose of this study was to determine if athletes have an increased risk of lower extremity musculoskeletal injury after return to play from a concussion. METHODS: Injury data were collected from 2006 to 2013 for men's football and for women's basketball, soccer and lacrosse at a National Collegiate Athletic Association Division I university. Ninety cases of in-season concussion in 73 athletes (52 male, 21 female) with return to play at least 30 days prior to the end of the season were identified. A period of up to 90 days of in-season competition following return to play was reviewed for time-loss injury. The same period was studied in up to two control athletes who had no concussion within the prior year and were matched for sport, starting status and position. RESULTS: Lower extremity musculoskeletal injuries occurred at a higher rate in the concussed athletes (45/90 or 50 %) than in the non-concussed athletes (30/148 or 20 %; P < 0.01). The odds of sustaining a musculoskeletal injury were 3.39 times higher in the concussed athletes (95 % confidence interval 1.90-6.05; P < 0.01). Overall, the number of days lost because of injury was similar between concussed and non-concussed athletes (median 9 versus 15; P = 0.41). CONCLUSIONS: The results of this study demonstrate a relationship between concussion and an increased risk of lower extremity musculoskeletal injury after return to play, and may have implications for current medical practice standards regarding evaluation and management of concussion injuries.

Observational ratings of frontal plane knee position are related to the frontal plane projection angle but not the knee abduction angle during a step-down task.

STUDY DESIGN: Laboratory study, cross-sectional. OBJECTIVES: To determine if the magnitude of frontal plane knee angle, as determined with a 3-D motion-capture system (knee abduction angle [KAA]) or digital video (frontal plane projection angle [FPPA]), varies among groups of individuals with different frontal plane knee position, as determined by observational ratings. BACKGROUND: Performing functional tasks with the knee positioned medial to the foot may increase the risk for knee injury. The KAA and FPPA are commonly used in research settings to determine injury risk. However, observational ratings of frontal plane knee position are easier to perform in the clinical setting. It is not clear whether observational ratings of knee position can be used as a surrogate for the KAA or FPPA. METHODS: Eighty-one female collegiate athletes performed a lateral step-down task. Participants were rated as good, fair, or poor based on observation of their knee position relative to the foot in the frontal plane and assigned to observational rating groups. Movement was concurrently recorded with a 3-D motion-capture system and a digital video camera to calculate KAA and FPPA, respectively. RESULTS: Knee abduction angle did not differ among participants assigned to the different observational rating groups (P = .265). In contrast, FPPA values differed between groups (P<.001), with the highest values in the poor group and the lowest values in the good group. CONCLUSION: Observational ratings of frontal plane knee position relative to the foot are an appropriate clinical substitute for FPPA but not KAA. Therefore, observational ratings of medial knee position may be more suitable as a clinical screening tool when FPPA is the measure of interest.

The association of pain and fear of movement/reinjury with function during anterior cruciate ligament reconstruction rehabilitation.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To measure fear of movement/reinjury levels and determine the association with function at different timeframes during anterior cruciate ligament (ACL) reconstruction rehabilitation. We hypothesized that fear of movement/reinjury would decrease during rehabilitation and be inversely related with function. BACKGROUND: Fear of movement/reinjury can prevent return to sports after ACL reconstruction, but it has not been studied during rehabilitation. METHODS AND MEASURES: Demographic data and responses on the shortened version of Tampa Scale for Kinesiophobia (TSK-11), 8-Item Short-Form Health Survey (SF-8), and International Knee Documentation Committee (IKDC) subjective form were extracted from a clinical database for 97 patients in the first year after ACL reconstruction. Three groups were formed: group 1, less than or equal to 90 days; group 2, 91 to 180 days; group 3: 181 to 372 days post-ACL reconstruction. Group differences in TSK-11 score, SF-8 bodily pain rating, and IKDC scores were determined. Hierarchical linear regression models were created for each group, with IKDC score as the dependent variable and demographic factors, SF-8 bodily pain rating, and TSK-11 score as independent variables. RESULTS: TSK-11 score was higher in group 1 than in group 3 (P < .05). Across the groups, SF-8 bodily pain rating decreased (P < .001) and IKDC score increased (P < .001). SF-8 bodily pain rating was a significant factor in the regression model for all groups, whereas TSK-11 score only contributed to the regression model in group 3 (partial correlation, -0.529). CONCLUSIONS: Pain was consistently associated with function across the timeframes studied. Fear of movement/reinjury levels appear to decrease during ACL reconstruction rehabilitation and are associated with function in the timeframe when patients return to sports. LEVEL OF EVIDENCE: Prognosis, level 4.

Savings sharing: rewarding staff for responsible decision-making.

Shortages of professional nurses create a "buyer's market" in which nurses accept temporary assignments for the highest rates and offer little additional time to the primary employer. Use of temporary personnel use salary dollars at an inordinate rate while offering little continuity or support for the organization's standards. Methods for placing decision-making in the hands of the nurses are needed along with a reward system for establishing a pattern of sound decision-making. The author describes a savings sharing program that is gaining credibility in one organization for addressing both objectives.