Analysis of strength and endurance in fast twitch skeletal muscle after an acute in vitro exposure to an anabolic steroid.

Forty extensor digitorum longus (EDL) muscles from adult rats were used in an in vitro experiment to determine the effects of an anabolic steroid on strength and endurance. Experimental muscles, exposed to a 1 x 10(-3) M testosterone propionate, were compared in strength and endurance to control muscles. Multivariate repeated measures analyses of variance and covariance, and univariate pooled variance t-tests showed the control muscles to be significantly (alpha less than or equal to 0.025) stronger and more durable than the steroid exposed muscles. The results failed to support the notion that steroids enhance contractile strength and endurance in skeletal muscle. It is speculated that steroids may block important mechanisms of muscle contraction, resulting in a decrease in force production.