The phrase "peak contraction" means the strongest and tightest the muscles can become during an exercise or physical activity. It refers to the moment when the muscles are at their maximum level of contraction and tension.
Using cables and machines are a superior way in which you can experience peak contraction in comparison to using dumbbells. (fitnessandpower.com)
We already know that strength is very joint angle - specific, especially when we compare exercises that produce peak contractions at either long or short muscle lengths. (strengthandconditioningresearch.com)