title: Enhancement of jump performance after a 5-RM squat is associated with postactivation potentiation.
abstract: Weight lifting exercise may induce postactivation potentiation (PAP), thereby enhancing performance of a subsequent biomechanically similar "explosive" movement. However, it has not been shown that weight lifting induces PAP, indicated as potentiation of muscle twitch force. Therefore, the present study tested whether a five repetition maximum squat (5-RM squat) both induced PAP and increased the height of subsequently performed counter-movement jumps (CMJs). Eleven male athletes completed four laboratory sessions on separate days. Two sessions determined whether the 5-RM squat induced PAP: in one, a quadriceps maximal twitch was evoked immediately before and 8 min after a set of five CMJs (control); in the other, a twitch was evoked before a CMJ set, which was followed by a 4-min rest, a 5-RM squat, a 4-min rest, and a second twitch. Another two sessions tested the effect of the 5-RM squat on jump performance: in one session, two sets of five CMJs were performed with an 8-min rest between the sets (control); in the second, a 5-RM squat was performed 4 min after the first set of CMJs, and then after another 4 min the second set of CMJs was performed. Neither twitch torque nor CMJ height changed in the control sessions (P > 0.05). In contrast, interpolation of the 5-RM squat increased (P < 0.05) both twitch torque (49.5 ± 7.8 to 54.8 ± 11.9 N m; i.e., PAP = 10.7%) and CMJ height (48.1 ± 5.6 to 49.5 ± 5.9 cm; 2.9%). Since PAP was present at the time when CMJ height increased, it was concluded that PAP may have contributed to the increased CMJ height after a 5-RM squat.
authors.affiliation: Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4K1, Canada. mitchc4@mcmaster.ca
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Mitchell
authors.forename: Digby G
authors.initials: DG
authors.lastname: Sale
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000293:Adolescent; D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D004576:Electromyography; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D010812:Physical Stimulation; D011187:Posture / Q000502:physiology; D012420:Running / Q000502:physiology; D013177:Sports / Q000502:physiology*; D019415:Torque; D014891:Weight Lifting / Q000502:physiology*; D055815:Young Adult