Resting your muscles

You can lift weights on consecutive days — just don’t exercise the same muscle two days in a row. Forty-eight hours is usually the ideal waiting period before exercising the same muscle group again. Lifting weights tears apart your muscle cells. Your muscles need a day to rest and repair so they come back even stronger.
If you ignore this rule, weight lifting may make you weaker rather than stronger. At the very least, your muscles feel too tired to perform at peak operating levels.