title: A functional fatiguing protocol and deceleration time of the shoulder from an internal rotation perturbation.
abstract: BACKGROUND
  Muscular fatigue impedes sensorimotor function and may increase the risk of shoulder injury during activity. The effects of fatigue on the sensorimotor system of the shoulder have been studied with various results. Deceleration times have been used to study neuromuscular control of the shoulder; however, no studies involving the effects of fatigue on deceleration times have been reported.
  
  
  OBJECTIVE
  To compare shoulder deceleration times after a shoulder internal rotation perturbation before and after a repetitive throwing exercise protocol.
  
  
  METHODS
  A 2 x 2 repeated-measures design.
  
  
  METHODS
  Exercise and sport injury laboratory.
  
  
  METHODS
  Twenty healthy, recreationally active men (age = 24.76 +/- 4.03 years, height = 178.41 +/- 8.36 cm, mass = 80.16 +/- 15.20 kg) volunteered to participate in the study. To ensure familiarity with the overhead motion, all subjects chosen had previously participated in an overhead throwing sport.
  
  
  METHODS
  The independent variables were time (preintervention and postintervention) and session (experimental and control). The intervention consisted of continuous overhead throwing. The subjects were considered fatigued when a 10% decrease in velocity was noted on 3 consecutive pitches.
  
  
  METHODS
  Time necessary to decelerate from an internal rotation perturbation.
  
  
  RESULTS
  Deceleration time was significantly increased by the fatiguing intervention ( P = .001).
  
  
  CONCLUSIONS
  The decreased ability to decelerate may be an adaptive response by the subjects to dissipate a lower percentage of force per second.
authors.affiliation: School of Health Science and Human Performance, Lynchburg College, Lynchburg, VA, USA. bowman.t@lynchburg.edc
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Bowman
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
authors.forename: Brian A
authors.initials: BA
authors.lastname: McGuire
authors.forename: Riann M
authors.initials: RM
authors.lastname: Palmieri
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Ingersoll