If you attempt the same exercise before complete recovery, you will notice a strength deficit. This is why recovery nutrition is so important.
Optimal recovery is highly dependent on an adequate supply of essential amino acids. Therefore, providing yourself with a high quality protein such as whey may mitigate the strength loss associated with intense unaccustomed exercise.
Australian researchers had two groups of untrained men perform a bout of single leg resistance exercise consisting of four sets of leg press, leg extension and leg flexion, emphasizing the eccentric portion of the movement. The load was 120% of their maximum concentric lift for each exercise.
Immediately after exercise, and continuing for 14 days, one group consumed 35g of whey protein isolate three times per day. The other group consumed 35g of carbohydrate.
As expected, strength measures were significantly decreased compared to pre-exercise levels. In the carbohydrate group, isometric strength declined 21% after one day and progressively returned to pre-exercise levels over the next 14 days. In contrast, the whey protein group only showed a 12% decline in strength and they were nearly back to pre-exercise strength levels in four days.
This study shows that consuming whey protein isolate after damaging exercise results in less loss in strength and faster recovery.