Muscle strength, volume and activation following 12-month resistance training in 70-year-old males.

In elderly males muscle plantar flexor maximal voluntary contraction (MVC) torque normalised to muscle volume (MVC/VOL) is reduced compared to young males as a result of incomplete muscle activation in the elderly. The aim of the present study was to determine the influence of a 12-month resistance training programme on muscle volume, strength, MVC/VOL, agonist activation and antagonist coactivation of the plantarfexors in elderly males. Thirteen elderly males aged 70 years and over (range 70-82 years), completed a 12-month whole body resistance-training programme (TRN), training three times a week. Another eight males (range 18-30 years), who maintained their habitual physical activity for the same 12-month period as the TRN group acted as controls (CTRL). Isometric plantarflexor maximal voluntary contraction (MVC) torque increased in the TRN group by 20% (P < 0.01), from 113.1 +/- 22.0 Nm to 141.5 +/- 19.2 Nm. Triceps surae volume (TS VOL) assessed using MRI, increased by 12%, from 796.3 +/- 78.9 cm(3) to 916.8 +/- 144.4 cm(3) . PF activation, measured using supramaximal double twitch interpolation, increased from 83.6+/-11.0% pre training, to 92.1 +/- 7.6% post training (P < 0.05). Dorsiflexion MVC and antagonist coactivation (assessed using surface electromyography) did not change with training. Plantarflexor MVC torque normalized for triceps surae muscle volume (MVC/VOL) was 142.6 +/- 32.4 kN m(-2) before training and 157.0 +/- 27.9 kN m(-2) after training (a non-significant increase of 8%). No significant change in any measurement was observed in the CTRL group. This study has shown that the gain in muscle strength in response to long-term (12-month) training in older men is mostly accounted for by an increased muscle volume and activation.