Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises
ABSTRACT Although closed (CKCE) and open (OKCE) kinetic chain exercises are used in athletic training and clinical environments, few studies have compared knee joint biomechanics while these exercises are performed dynamically. The purpose of this study was to quantify knee forces and muscle activity in CKCE (squat and leg press) and OKCE (knee extension).
Ten male subjects performed three repetitions of each exercise at their 12-repetition maximum. Kinematic, kinetic, and electromyographic data were calculated using video cameras (60 Hz), force transducers (960 Hz), and EMG (960 Hz). Mathematical muscle modeling and optimization techniques were employed to estimate internal muscle forces.
Overall, the squat generated approximately twice as much hamstring activity as the leg press and knee extensions. Quadriceps muscle activity was greatest in CKCE when the knee was near full flexion and in OKCE when the knee was near full extension. OKCE produced more rectus femoris activity while CKCE produced more vasti muscle activity. Tibiofemoral compressive force was greatest in CKCE near full flexion and in OKCE near full extension. Peak tension in the posterior cruciate ligament was approximately twice as great in CKCE, and increased with knee flexion. Tension in the anterior cruciate ligament was present only in OKCE, and occurred near full extension. Patellofemoral compressive force was greatest in CKCE near full flexion and in the mid-range of the knee extending phase in OKCE.
An understanding of these results can help in choosing appropriate exercises for rehabilitation and training.
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- "Contrary to the present findings, GM was not the last muscle to be recruited and the discrepancy may be explained by variations in methodology; the prone hip extension is classified as an open chain nonweight bearing exercise and DL, is an orthostatic, closed chain weight-bearing exercise. It is likely that open and closed chain exercises have different muscle strategies; for example, Escamilla et al. (1998) observed hamstring EMG activity was doubled during 12 RM barbell squat (closed chain exercise) compared with 12 RM seated knee extension (open chain exercise). Lehman et al. (2004) have expressed concerns with the use of the prone hip extension and have argued for additional functional exercises to be assessed. "
ABSTRACT: The aim of this study was to determine the muscle activity and onset time of hip extensors during a closed kinetic chain exercise (deadlift) at sub-maximal loads of 30%, 40%, 50%, and 75% of one repetition maximum (1RM). Twelve healthy males with at least three years of resistance training experience volunteered for the study. Biceps femoris (BF) and gluteus maximus (GM) muscle activity, onset time, peak and mean power were measured during the concentric phase of the deadlift. There was no main effect (p > 0.05) or no interaction effect for the onset time in BF and GM and for each load BF and GM had similar muscle activity. Increasing the external load during deadlift had no adverse effect on the relative onset time and it did not promote BF onset to occur before GM onset, thus both muscles were simultaneously activated, which should not compromise a delay in GM.Research in Sports Medicine 02/2015; 23(2):1-11. DOI:10.1080/15438627.2015.1005299 · 1.70 Impact Factor
- "sEMG) during the extension and flexion actions of the leg muscles was recorded from the vastus lateralis (VL), vastus medialis (VM) and the short head of the bicep femoris (BF) of the right leg by a pair of bipolar surface electrodes (Blue Sensor N-00-S, Medicotest) with a distance between the electrode's centres of 22 mm. The agonists vastus lateralis (VL) and vastus medialis (VM) muscles were averaged because they have demonstrated similar patterns of activation during bilateral leg press exercise (Escamilla et al. 1998 "
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- "Thus, individuals who suffer from tibiofemoral pathologies should avoid performing the squat at high flexion angles. It has been reported that the CF was slightly higher during the descent phase compared with the ascent phase (Escamilla et al., 1998). The same result was demonstrated for the neutral squat, but not for the squeeze squat and outward squat in this study. "
ABSTRACT: The squat exercise was usually performed with varying feet and hip angles by different populations. The objective of this study was to compare and contrast the three-dimensional knee angles, moments, and forces during dynamic squat exercises with varying feet and hip angles. Lower extremity motions and ground reaction forces for fifteen healthy subjects (9 females and 6 males) were recorded while performing the squat with feet pointing straight ahead (neutral squat), 30º feet adduction (squeeze squat) and 30º feet abduction (outward squat). Nonparametric procedures were used to detect differences in the interested measures between the conditions. No significant difference in three-dimensional peak knee angles was observed for three squat exercises (p>0.05), however, the overall tendency of knee rotations was affected by varying feet and hip positions. During the whole cycle, the outward squat mainly displayed adduction moments, while the neutral and squeeze squat demonstrated abduction moments. Peak abduction moments were significantly affected by feet positions (p<0.05). Moreover, the tibiofemoral and patellofemoral joint forces progressively increased as knee flexed and decreased as knee extended, yet peak forces were not affected by varying feet positions (p>0.05). In conclusion, a neutral position is recommended to perform the squat exercise, while the squeeze squat and outward squat might contribute to the occurrence of joint pathologies.Journal of Human Kinetics 12/2013; 39(1):59-66. DOI:10.2478/hukin-2013-0068 · 0.70 Impact Factor