EFFECT OF A 6-WEEK ENDURANCE TRAINING-PROGRAM AND BRANCHED-CHAIN AMINO-ACID SUPPLEMENTATION ON HISTOMORPHOMETRIC CHARACTERISTICS OF AGED HUMAN MUSCLE

The effects of a 6-week endurance training programme and a branched-ch ain amino acid (BCAA) supplementation were investigated on skeletal mu scle histomorphometric characteristics of elderly men. Seventeen elder ly men, age (63 +/- 5 years), height (173 +/- 5 cm) and weight (75 +/- 8 kg) were included in the study. One group (n = 9) received an oral BCAA supplementation for 6 weeks (16, 2 and 2 g per day of leucine, is oleucine and valine, respectively), while another group (n = 8) receiv ed a placebo. During these 6 weeks, subjects trained on a Monark cycle ergometer at 75 +/- 9 % of their maximal heart rate for 1 h/day, 4 da ys/week. Muscle biopsy samples taken at rest before and after enduranc e training were analyzed for capillarization, fibre type distribution and fibre area. As a result of endurance training, maximal oxygen upta ke was significantly increased by about 5 % in control and BCAA supple mented groups (P < 0.01). The number of capillaries per fibre and in c ontact with type I fibres was significanly increased (P < 0.05), this effect being similar in control and BCAA supplemented groups. The perc entage distribution and area of type I, type IIa and type IIb fibres d id not differ between the two groups and remained unchanged with endur ance training. It is concluded that skeletal muscle of elderly men can adapt to a 6-week endurance training programme and that a BCAA supple mentation does not further enhance the induced histomorphometric chang es.