title: Potentiation and recovery following low- and high-speed isokinetic contractions in boys.
abstract: The objective of this study was to examine the response and recovery to a single set of maximal, low and high angular velocity isokinetic leg extension-flexion contractions with boys. Sixteen boys (11-14 yrs) performed 10 isokinetic contractions at 60°.s-1 (Isok60) and 300°.s-1 (Isok300). Three contractions at both velocities, blood lactate and ratings of perceived exertion were monitored pretest and at 2, 3, 4, and 5 min of recovery (RI). Participants were tested in a random counterbalanced order for each velocity and recovery period. Only a single contraction velocity (300°.s-1 or 60°.s-1) was tested during recovery at each session to remove confounding influences between the recovery intervals. Recovery results showed no change in quadriceps' power at 300°.s-1, quadriceps' power, work and torque at 60°.s-1 and hamstrings' power and work with 60°.s-1. There was an increase during the 2 min RI in hamstrings' power, work and torque and quadriceps' torque with isokinetic contractions at 300°.s-1 suggesting a potentiating effect. Performance impairments during recovery occurred for the hamstrings torque at 60°.s-1 and quadriceps work with 300°.s-1. In conclusion, 10 repetitions of either low or high velocity isokinetic contractions (Isok60 or Isok300) resulted in full recovery or potentiation of most measures within 2 min in boys. The potentiation effect predominantly occurred following the hamstrings Isok300 which might be attributed to a greater agonist-antagonist torque balance and less metabolic stress associated with the shorter duration higher velocity contractions.
authors.affiliation: Tunisian Research Laboratory, Sports Performance Optimization, National Center of Medicine and Science in Sports, Tunis, Tunisia.
authors.forename: Anis
authors.initials: A
authors.lastname: Chaouachi
authors.forename: Monoem
authors.initials: M
authors.lastname: Haddad
authors.forename: Carlo
authors.initials: C
authors.lastname: Castagna
authors.forename: Del P
authors.initials: del P
authors.lastname: Wong
authors.forename: Fathi
authors.initials: F
authors.lastname: Kaouech
authors.forename: Karim
authors.initials: K
authors.lastname: Chamari
authors.forename: David G
authors.initials: DG
authors.lastname: Behm
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D003163:Competitive Behavior; D017079:Exercise Tolerance / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D016139:Martial Arts / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010465:Perception; D052097:Quadriceps Muscle / Q000502:physiology*; D015203:Reproducibility of Results; D055070:Resistance Training; D013848:Thigh / Q000502:physiology*; D013997:Time Factors; D019415:Torque
chemical_list: D019344:Lactic Acid