Acute Effects of Neuromuscular-Training with Handheld-Vibration on Elbow Joint Position Sense

Context: Clinicians use exercises in rehabilitation to enhance sensorimotor-function, however evidence supporting their use is scarce. Objective: To evaluate acute effects of handheld-vibration on joint position sense (JPS). Design: A repeated-measure, randomized, counter-balanced 3-condition design. Setting: Sports Medicine and Science Research Laboratory. Patients or Other Participants: 31 healthy college-aged volunteers (16-males, 15-females; age=23+3y, mass=76+14kg, height=173+8cm). Interventions: We measured elbow JPS and monitored training using the Flock-of-Birds system (Ascension Technology, Burlington, VT) and MotionMonitor software (Innsport, Chicago, IL), accurate to 0.5°. For each condition (15,5,0Hz vibration), subjects completed three 15-s bouts holding a 2.55kg Mini-VibraFlex dumbbell (Orthometric, New York, NY), and used software-generated audio/visual biofeedback to locate the target. Participants performed separate pre- and post-test JPS measures for each condition. For JPS testing, subjects held a non-vibrating dumbbell, identified the target (90°flexion) using biofeedback, and relaxed 3-5s. We removed feedback and subjects recreated the target and pressed a trigger. We used SPSS 14.0 (SPSS Inc., Chicago, IL) to perform separate ANOVAs (p<0.05) for each protocol and calculated effect sizes using standard-mean differences. Main Outcome Measures: Dependent variables were absolute and variable error between target and reproduced angles, pre-post vibration training. Results: 0Hz (F1,61=1.310,p=0.3) and 5Hz (F1,61=2.625,p=0.1) vibration did not affect accuracy. 15Hz vibration enhanced accuracy (6.5±0.6 to 5.0±0.5°) (F1,61=8.681,p=0.005,ES=0.3). 0Hz did not affect variability (F1,61=0.007,p=0.9). 5Hz vibration decreased variability (3.0±1.8 to 2.3±1.3°) (F1,61=7.250,p=0.009), as did 15Hz (2.8±1.8 to 1.8±1.2°) (F1,61=24.027, p<0.001). Conclusions: Our results support using handheld-vibration to improve sensorimotor-function. Future research should include injured subjects, functional multi-joint/multi-planar measures, and long-term effects of similar training.

Coach Behaviors and Athlete Satisfaction in Team and Individual Sports

The coach can have a profound impact on athlete satisfaction, regardless of the level of sport involvement. Previous research has identified differences between coaching behavior preferences in team and individual sport athletes. The present study examined the moderating effect that an athlete's sport type (i.e., individual or team) may have on the relationships among seven coaching behaviors (mental preparation, technical skills, goal setting, physical training, competition strategies, personal rapport, and negative personal rapport) for predicting coaching satisfaction. Moderated multiple regression analyses indicated that each of the seven coaching behaviors were significant main effect predictors of coaching satisfaction. However, sport type (i.e., team or individual sports) was found to moderate six of the seven relationships: mental preparation, technical skills, goal setting, competition strategies, personal rapport, and negative personal rapport in predicting satisfaction with the coach. These findings indicate that high coaching satisfaction for athletes in team sports is influenced to a greater extent by the demonstration of these behaviors than it is for individual sport athletes.