Muscle Fiber Characteristics of Competitive Power Lifters

Abstract

To examine the skeletal muscle characteristics of power lifters, 5 competitive power lifters (PL; X ± SE; age 5 31.0 ± 1.5 years, squat 5 287.7 ± 15.7 kg, bench press 5 170.5 ± 17.7 kg, and deadlift 5 284.2 ± 7.5 kg) and 5 untrained control subjects (CON; age = 27.3 ± 3.3 years) served as subjects. Iso-kinetic squat force and power was greater (p < 0.05) for the PL at all bar velocities (0.20, 0.82, and 1.43 m · s1), as was vertical jump height and estimated power. Muscle biopsies from the vastus lateralis m. revealed significant differences for percent fiber type (PL, IIA 5 45.5 ± 1.6%, IIB 5 1.3 ± 0.8%; CON, IIA 5 33.4 ± 3.1%, IIB 5 12.0 ± 2.4%); percent fiber type area (PL, IIA 5 51.8 ± 1.6%, IIB 5 1.3 ± 0.8%; CON, IIA 5 43.5 ± 3.4%, IIB 5 12.4 ± 2.6%); and percent myosin heavy chain isoform (PL, IIa 5 59.5 ± 6.1%; CON, 46.5 ± 2.5%). Muscle fiber characteristics were significantly correlated (r = 6 0.61) with numerous strength and power measures for the PL. These data illustrate the muscle fiber characteristics necessary for the maximal force production requirements of power lifting.