Is there an optimal training intensity for enhancing the maximal oxygen uptake of distance runners? Empirical research findings, current opinions, physiological rationale and practical recommendations

Abstract

The maximal oxygen uptake (V̇O2max) is considered an important physiological determinant of middle- and long-distance running performance. Little information exists in the scientific literature relating to the most effective training intensity for the enhancement of V̇O 2max in well trained distance runners. Training intensities of 40-50% V̇O2max can increase V̇O2max substantially in untrained individuals. The minimum training intensity that elicits the enhancement of V̇O2max is highly dependent on the initial V̇O2max, however, and well trained distance runners probably need to train at relative high percentages of V̇O2max to elicit further increments. Some authors have suggested that training at 70-80% V̇O2max is optimal. Many studies have investigated the maximum amount of time runners can maintain 95-100% V̇O2max with the assertion that this intensity is optimal in enhancing V̇O2max. Presently, there have been no well controlled training studies to support this premise. Myocardial morphological changes that increase maximal stroke volume, increased capillarisation of skeletal muscle, increased myoglobin concentration, and increased oxidative capacity of type II skeletal muscle fibres are adaptations associated with the enhancement of V̇O2max. The strength of stimuli that elicit adaptation is exercise intensity dependent up to V̇O2max, indicating that training at or near V̇O 2max may be the most effective intensity to enhance V̇O 2max in well trained distance runners. Lower training intensities may induce similar adaptation because the physiological stress can be imposed for longer periods. This is probably only true for moderately trained runners, however, because all cardiorespiratory adaptations elicited by submaximal training have probably already been elicited in distance runners competing at a relatively high level. Well trained distance runners have been reported to reach a plateau in V̇O2max enhancement; however, many studies have demonstrated that the V̇O2max of well trained runners can be enhanced when training protocols known to elicit 95-100% V̇O2max are included in their training programmes. This supports the premise that high-intensity training may be effective or even necessary for well trained distance runners to enhance V̇O2max. However, the efficacy of optimised protocols for enhancing V̇O2max needs to be established with well controlled studies in which they are compared with protocols involving other training intensities typically used by distance runners to enhance V̇O2max. © 2006 Adis Data Information BV. All rights reserved.