Knee angle-dependent oxygen consumption during isometric contractions of the knee extensors determined with near-infrared spectroscopy

Abstract

Ruiter, C. J. de, M. D. de Boer, M. Spanjaard, and A. de Haan. Knee angle-dependent oxygen consumption during isometric contractions of the knee extensors determined with near-infrared spectroscopy. J Appl Physiol 99: 579 -586, 2005. First published March 17, 2005; doi:10.1152/japplphysiol.01420.2004.-Fatigue resistance of knee extensor muscles is higher during voluntary isometric contractions at short compared with longer muscle lengths. In the present study we hypothesized that this would be due to lower energy consumption at short muscle lengths. Ten healthy male subjects performed isometric contractions with the knee extensor muscles at a 30, 60, and 90°knee angle (full extension ϭ 0°). At each angle, muscle oxygen consumption (mV O2) of the rectus femoris, vastus lateralis, and vastus medialis muscle was obtained with near-infrared spectroscopy. mV O2 was measured during maximal isometric contractions and during contractions at 10, 30, and 50% of maximal torque capacity. During all contractions, blood flow to the muscle was occluded with a pressure cuff (450 mmHg). mV O2 significantly (P Ͻ 0.05) increased with torque and at all torque levels, and for each of the three muscles mV O2 was significantly lower at 30°compared with 60°a nd 90°and mV O2 was similar (P Ͼ 0.05) at 60°and 90°. Across all torque levels, average (Ϯ SD) mV O2 at the 30°angle for vastus medialis, rectus femoris, and vastus lateralis, respectively, was 70.0 Ϯ 10.4, 72.2 Ϯ 12.7, and 75.9 Ϯ 8.0% of the average mV O2 obtained for each torque at 60 and 90°. In conclusion, oxygen consumption of the knee extensors was significantly lower during isometric contractions at the 30°than at the 60°and 90°knee angle, which probably contributes to the previously reported longer duration of sustained isometric contractions at relatively short muscle lengths. energy utilization; submaximal isometric contractions; voluntary activation; fatigue TIME TO FORCE FAILURE DURING a single voluntary submaximal isometric muscle contraction is inversely related to knee extensor muscle length (16,21,26,31). Apparently, submaximal isometric contractions are less fatiguing at short muscle lengths compared with isometric contractions made at the same relative torque level but at longer muscle lengths. For tibialis anterior muscle it has been suggested (13) that the cause for the lower fatigability at short muscle lengths would be the lower energetic cost due to fewer cross-bridge interactions at short length compared with lengths that are closer to optimal overlap between actin and myosin filaments. However, two studies that explicitly investigated the idea of a length-dependent energy utilization in tibialis anterior muscle using 31 P-magnetic resonance spectroscopy ( 31 P-MRS) failed to show length-dependent energy consumption (2, 34).Recently, Place et al. (31) related the lower fatigability at short muscle lengths to a greater twitch potentiation at short compared with a longer length after a voluntary sustained contraction of the knee extensors at 20% maximal volun...

Effect of Caffeine on Fatigue During Submaximal Isometric Contractions at Different Knee Angles

“…Nonetheless, both Baker et al [7] and Sacco et al [40] showed similar ATP use at short compared to optimum muscle lengths with nuclear magnetic resonance spectroscopy. However, more recently de Ruiter et al [6] showed during a sustained isometric contraction lower muscle oxygen consumption at 30° compared to 60° and 90°. They concluded that this represented lower energy consumption at 30° and there would therefore be lower metabolic changes (specifically reduced pH and increased inorganic phosphate) and the lower negative consequences caused by these changes.…”

“…The number of active cross bridges and their subsequent energy consumption may be related to endurance [5]. Although De Ruiter et al showed that muscle oxygen consumption during a sustained isometric contraction was lower at 30° compared to 90° [6], the ATP use at these different knee angles was shown to be similar [7]. Thus, it appears that mechanisms responsible for the length dependent endurance of isometric contractions are equivocal.…”

Effects of isometric training on the knee extensor moment–angle relationship and vastus lateralis muscle architecture

“…The group that trained at long muscle lengths probably underwent greater metabolic stress, because for the same contraction time, oxygen consumption and, therefore fatigue (de Ruiter et al 2005) would have been greater than those in the group that trained at short muscle lengths (Philippou et al 2004). Blazevich et al (2007) reported no differences in fascicle lengthening after an only-concentric or only-eccentric strength training period.…”

The repeated-bout effect: influence on biceps brachii oxygenation and myoelectrical activity

“…Therefore, changes in muscle oxygenation during sustained isometric contractions Ͼ50% MVC could primarily provide information on muscle O 2 consumption, which is a measure of the energy consumption for muscle force production (10). During repeated isometric contractions, in contrast, reoxygenation is permitted during the relaxation phases; therefore, the changes in muscle oxygenation provide additional information on the regulation of O2 supply to meet the muscle metabolic demand for O2 (39).…”