Effects of high volume upper extremity plyometric training on throwing velocity and functional strength ratios of the shoulder rotators in collegiate baseball players.

To achieve maximal force output, clinicians and coaches have been experimenting with upper extremity plyometric exercises for years, without sufficient scientific validation of this training method. The goal of this study was to examine the effects of an 8-week course of high volume upper extremity plyometric training on the isokinetic strength and throwing velocity of a group of intercollegiate baseball players. Twenty-four Division I collegiate baseball players (age: 19.7 +/- 1.3 years; height: 183.9 +/- 5.9 cm; mass: 90.7 +/- 10.5 kg) were recruited to participate in this study. Throwing velocity, isokinetic peak torque, isokinetic functional strength ratios, and time to peak torque were measured pre- and posttraining. Subjects were rank-ordered according to concentric internal rotation (IR) strength and were assigned randomly to either the plyometric training group (PLY) or the control group (CON). Training consisted of 6 upper extremity plyometric exercises ("Ballistic Six") performed twice per week for 8 weeks. Subjects assigned to CON performed regular off-season strength and conditioning activities, but did not perform plyometric activities. PLY demonstrated significant increases (p < 0.05) in throwing velocity following 8 weeks of training when compared with CON (83.15 mph [pre] vs. 85.15 mph [post]). There were no statistically significant differences in any of the isokinetic strength measurements between PLY and CON groups pre- to posttraining. Statistically significant differences were seen within PLY for concentric IR and eccentric external rotation (ER) isokinetic strength at 180 degrees x s(-1) and 300 degrees x s(-1); and within CON for eccentric ER isokinetic strength at 300 degrees x s(-1) and concentric IR isokinetic strength at 180 degrees x s(-1). The Ballistic Six training protocol can be a beneficial supplement to a baseball athlete's off-season conditioning by improving functional performance and strengthening the rotator cuff musculature.

Reliability of upper extremity anaerobic power assessment in persons with tetraplegia.

BACKGROUND/OBJECTIVE: Reliable assessment of upper extremity anaerobic power in persons with cervical spinal cord injury (SCI) may indicate the ability to successfully and safely perform many daily activities. PURPOSE: To examine test-retest reliability of upper extremity Wingate anaerobic testing (WAnT) in persons with motor/sensory complete tetraplegia. METHODS: Forty-five persons with cervical-level SCI (15 individuals each at C5, C6, and C7 levels of injury) performed 2-arm WAnT bouts, with 2 to 4 days between bouts. Subjects performed the WAnT seated in their wheelchairs using a tabletop-mounted Monarch 834E ergometer. Resistance loads were applied relative to injury level, with 1%, 2%, and 3% of body mass applied to subjects with C5, C6, and C7 level injuries, respectively. All subjects were directed to crank the ergometer at maximal velocity for a 30-second period. Values of peak power (Ppeak) and mean power (Pmean) were determined using an SMI OptoSensor 2000 system. Ppeak and Pmean were compared between trials and between groups using 2-way analyses of variance for repeated measures. Coefficients of determination (r2) were calculated between trials. RESULTS: There were no significant differences in Ppeak or Pmean detected between the 2 trials of WAnT in the C5, C6, or C7 groups. Regression analyses revealed statistically significant associations between bouts for Pmean and Ppeak in each of the 3 groups (P < 0.05). CONCLUSIONS: Upper extremity WAnT is reliable for upper extremity anaerobic power assessment in persons with cervical SCI at or below the C5 level.

Effect of variable loading in the determination of upper-limb anaerobic power in persons with tetraplegia.

This article examines the effects of levels of resistance loading during arm Wingate Anaerobic Testing (WAnT) in persons with differing levels of cervical spinal cord injury (SCI). Thirty-nine persons with motor-complete SCI tetraplegia (13 each at C5, C6, and C7) performed six bouts of arm-crank WAnT with relative loads equivalent to 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 percent of body mass (BM). Power output was determined with the use of the SMI OptoSensor 2000 (Sports Medicine Industries, Inc., St. Cloud, MN, USA) hardware and software package. Values of peak power (P(peak)) and mean power (P(mean)) were examined statistically between groups (C5, C6, and C7) and across levels of resistance loading. Resistance loads that provided the greatest values of P(mean) for the three groups were as follows: C5 = 1.0 or 1.5 percent of BM; C6 = 1.5 or 2.0 percent of BM; and C7 = 2.5, 3.0, or 3.5 percent of BM. Appropriate loading for arm WAnT is specific to the level of tetraplegia and may provide a useful assessment of upper limb power production.