Influence of Acute Endurance Activity on Isokinetic Strength

Abstract

The purpose of the investigation was to determine whether low-intensity continuous (LSD) or high-intensity interval (INT) endurance activity prior to isokinetic strength assessment reduced torques generated 0.52 rad (30°) prior to horizontal (T 30 ). T 30 was measured at 10 contractile speeds (0.52-5.20 rad s-1) prior to and following the LSD and INT exercise bouts. Six males (23.2 ±3.3 yrs, 74.9 ±6.8 kg, 177.6 ±5.4 cm) with a mean peak cycle ergometer oxygen consumption (PCE VO 2 ) of 3.85 (±0.33) Lmin-1completed 150 min cycling at 35% PCE VO 2 in the LSD challenge. The 5 females and 3 males (20.8 +4.6 yrs, 63.2 ±12.0 kg, 168.8 ±8.5 cm, 2.51 ±0.78 L min-1) of the INT condition completed five 5-min repetitions in which the work rate was progressively increased from 40 to 100% PCE VO 2 . Both the LSD and INT regimens reduced T 30 at all contractile speeds. The reduction in T 30 was similarly small for the LSD and INT conditions when expressed as percentage of preintervention values and effect sizes. Small, acute reductions in strength as a result of temporally proximal endurance activity may partially explain the inhibition in strength development that has followed some concurrent strength and endurance training investigations.