Kinetic chain exercises

Open and closed kinetic chain excercises

Many clients continue to experience muscle weakness after rehabilitation and a deficiency in quadriceps strength is common in patients with poor functioning after injury. Yet therapists still lack an evidence base from which they can optimise treatment approaches. There is little consensus, for instance, on how best to restore quadriceps strength after anterior cruciate ligament (ACL) injury.

Now, researchers from the Division of Physiotherapy at Linköping University in Sweden have compared two common rehab approaches. The team wanted to find out whether open kinetic chain (OKC) exercises were more effective at strengthening the quadriceps than closed kinetic chain (CKC) exercises, when used as part of a comprehensive rehab programme (a comprehensive rehabilitation program with quadriceps strengthening in closed versus open kinetic chain exercises in patients with anterior cruciate ligament deficiency. The American Journal of Sports Medicine 2008: 36 (2) 298-307).

Forty-two patients with ACL injuries took part in the study. Their rehab consisted of exercises designed to develop neuromuscular control, strength, coordination and functional stability. For patients in the CKC group, single-leg squatting was the primary quadriceps strengthening exercise. Those in the OKC group were given seated single-leg knee extensions instead. The two programmes were otherwise identical.

The researchers assessed participants at the outset and again after four months on the programme, for various factors, including swelling and passive range of movement for knee extension and flexion, instrumented Lachman test, gait, single leg squat maximal isokinetic knee flexion/extension 1RM squat and vertical jump.

The results of the study showed that a comprehensive rehabilitation programme supplemented by an open kinetic chain quadriceps exercise leads to significantly greater quadriceps strength during an isokinetic test than the same programme supplemented by a closed kinetic chain exercise. However, the two groups performed similarly during the CKC muscle strength test (single-leg squat).

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