Muscle fiber type, Achilles tendon length, potentiation, and running economy.

Academic Article


  • The purpose of this investigation was to develop a potential model for how muscle fiber type, Achilles tendon length, stretch-shortening cycle potentiation (SSCP), and leg strength interact with running economy. Twenty trained male distance runners 24-40 years of age served as subjects. Running economy (net oxygen uptake) was measured while running on a treadmill. Leg press SSCP(force) and SSCP(velocity) were determined by measuring the difference in velocity between a static leg press throw and a countermovement leg press throw. Vertical jump SSCP was determined by measuring the difference in jump height between a static jump and a drop jump from a 20.3-cm bench. Tendon length was measured by magnetic resonance imaging, and muscle fiber type was made from a vastus lateralis muscle biopsy. Type IIx muscle fiber percent (r = 0.70, p < 0.001) and leg strength (r = 0.95, p < 0.001) were positively and independently related to late eccentric force development. Achilles tendon length (r = 0.42, p ≤ 0.05) and late eccentric force during stretch-shortening cycle (r = 0.76, p < 0.001) were independently related to SSCP(force). SSCP(force) was related to SSCP(velocity), which in turn was related to running economy (r = 0.61, p < 0.01). These results suggest that longer Achilles tendon length, type II fiber, and muscular leg strength may enhance the potential for SSCP, running economy, and physiological effort while running.
  • Keywords

  • Achilles Tendon, Adult, Exercise Test, Humans, Magnetic Resonance Imaging, Male, Muscle Contraction, Muscle Fibers, Skeletal, Muscle Strength, Oxygen Consumption, Quadriceps Muscle, Running, Weight Lifting, Young Adult
  • Digital Object Identifier (doi)

    Author List

  • Hunter GR; McCarthy JP; Carter SJ; Bamman MM; Gaddy ES; Fisher G; Katsoulis K; Plaisance EP; Newcomer BR
  • Start Page

  • 1302
  • End Page

  • 1309
  • Volume

  • 29
  • Issue

  • 5