Closed kinetic chain exercises vary considerably with respect to quadriceps-hamstrings co-contraction, which may have significant implications for rehabilitation, according to research from the University of North Carolina in Chapel Hill.
Investigators analyzed activation of the vastus medialis, vastus lateralis, medial hamstrings, and biceps femoris during nine different weight bearing exercises. Exercises included three lunges, three hop-to-balance exercises, single leg squat, single leg dead lift, and lateral band walk.
Quadriceps: hamstrings ratio ranged from 2.87 for the single leg deadlift to 9.70 for the forward lunge. In addition to the single leg deadlift, the most balanced exercises were the lateral hop test, the transverse hop test, and the lateral band walk.
“Not all closed kinetic chain exercises produce hamstrings activation,” said Rebecca Scanlon-Begalle, MA, ATC, a doctoral student in human movement science at the university, who presented her group’s findings at the NATA meeting. “Knowledge of quadriceps and hamstrings activation is vital for developing a rehabilitation program.”
Some of the exercises tested, however, could potentially be modified to alter the Q:H ratio, Scanlon-Begalle said.