The metabolic costs of different types of contractile activity of the human adductor pollicis muscle.
AUTOR(ES)
Newham, D J
RESUMO
1. The metabolic costs and physiological consequences of shortening contractions of a human muscle working in situ have been compared with those of the muscle maintaining a continuous isometric contraction and when performing repeated brief isometric contractions. 2. After a total of 10 s stimulation, the shortening and intermittent brief isometric protocols had very similar effects, causing a 30% loss of force and a threefold increase in the half-time of relaxation. This was in contrast to the continuous isometric contraction protocol where there was less than 10% loss of force or slowing of relaxation. 3. The ATP cost over the first 5 s of the continuous isometric protocol was 27 mmol (l intracellular water)-1 while for the shortening and repeated brief isometric protocols the costs were 48 and 46 mmol (l intracellular water)-1, respectively. 4. The results show that shortening and repeated brief isometric contractions are considerably more energetically demanding, and hence more fatiguing, than sustained isometric contractions.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1156747Documentos Relacionados
- The origin and innervation of the adductor pollicis muscle.
- Changes in maximal voluntary force of human adductor pollicis muscle during the menstrual cycle.
- Metabolic and contractile uniformity of isolated motor unit fibres of snake muscle.
- Structure and function of the abductor pollicis longus muscle.
- Adductor Pollicis Muscle Thickness as a Marker of Nutritional Status in Heart Failure