title: Relationships between stretch-shortening cycle performance and maximum muscle strength.
abstract: This study aimed to examine the relationships between muscle power output using the stretch-shortening cycle (SSC) and maximum strength, as measured by the 1 RM (1 repetition maximum) test and the isokinetic dynamometer under elbow flexion. Sixteen trained, young adult males pulled a constant load of 40% MVC (maximum voluntary elbow flexion contraction) by ballistic elbow flexion under the following two preliminary conditions: 1) the static relaxed muscle state (SR condition) and 2) using the SSC (SSC condition). Muscle power was determined from the product of the pulling velocity and load mass by a power measurement instrument with a rotary encoder. The 1 RM bench press (1RM BP) and isokinetic maximum strength under elbow flexion with the Cybex-325 were measured as indicators of dynamic maximum strength. 1) The early power output exerted under the SSC condition showed a significant and high correlation with the 1 RM BP (r = 0.83), but only moderate correlation with the isokinetic muscle strength (r = 0.50-0.67). 2) The contribution of the 1 RM BP to the early muscle contraction velocity exerted under the SSC condition was large. These results suggested that muscle power exerted using the SSC shows a stronger relationship with maximum muscle strength measured by a 1 RM test rather than isokinetic maximum strength.
authors.affiliation: Liberal Arts Education Center, Ishikawa Prefectural University, Ishikawa, Japan. kazu1060@lapis.plala.or.jp
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Miyaguchi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Demura
mesh_terms: D000328:Adult; D000886:Anthropometry; D015331:Cohort Studies; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D052580:Muscle Stretching Exercises / Q000379:methods*; D010806:Physical Education and Training / Q000379:methods; D010807:Physical Endurance / Q000502:physiology; D011336:Probability; D012680:Sensitivity and Specificity; D013647:Task Performance and Analysis; D034941:Upper Extremity / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology