Activity of the Quadriceps during Semisquat and Squat Exercises with Isometric Hip Adduction and Abduction in Young Healthy Persons

OBJECTIVE: To determine the effects of isometric hip adduction and abduction on the activity of vastus medialis obliquus (VMO) and vastus lateralis (VL) during semisquat and squat exercise. METHOD: Thirty healthy male subjects without history of knee pain were recruited. Subjects performed a traditional exercise combined with hip adduction and abduction during semisquat and squat exercise. A total of 3 repetitions lasting 6 seconds each were executed following two-minute intervals. The EMG signals were collected from VMO and VL of the dominant leg. The data were normalized to the maximal isometric voluntary contraction of VMO and VL at 90degrees of knee flexion using isokinetic dynamometer and analysed in terms of their RMS values. RESULTS: The activity of both VMO and VL was significantly greater during both semisquat and squat exercise with hip adduction and abduction than without hip adduction and abduction. The VMO/VL ratio was significantly greater. The squat exercise produced significantly greater VMO and VL activity than the semisquat exercise, regardless of hip position. However, there were no significant differences in VMO/VL ratio between semisquat and squat exercise. CONCLUSION: Combining isometric hip adduction using theraband during semisquat exercise produced higher VMO/ VL ratio through more selective VMO activation and could be easy and effective rehabilitation program in patellofemoral pain syndrome.

Effect of Concentric Isokinetic Knee Strength Training on Gait, Balance and Quality of Life in Chronic Stroke Patients

OBJECTIVE: To determine the effects of concentric isokinetic knee strength training on gait, balance and health related quality of life in chronic stroke patients. METHOD: Fifteen patients with chronic stroke participated in this study. All subjects were community ambulators and trained using Biodex System 3 isokinetic dynamometer three times a week for 6 weeks. The training program consisted of concentric isokinetic strengthening of both knee extensors and flexors. Peak torque of knee extensors and flexors, walking performance (temporospatial parameter of gait and stair climbing time), balance (overall balance index, anterior/ posterior index and medial/lateral index) and health-related quality of life measure (36-item short form health survey, SF-36) were evaluated before and after training period. RESULTS: Muscle strength improved significantly after training. Walking speed, stride length and stair climbing time improved significantly after training. Balance indices and SF-36 score also improved significantly after training. CONCLUSION: Gain in muscle strength appeared to be transferred to functional improvement. Therefore, isokinetic resistance training program would be one of the effective rehabilitation programs for chronic stroke survivors. Further investigations are required for long-term effect and development of strength-specific resistance training program.