Horizontal and Declined Squats in Healthy Individuals: A Study of Kinematic and Muscle Patterns (original) (raw)
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Kinematic, kinetic and EMG patterns during downward squatting
… of Electromyography and …, 2008
The aim of this study was to investigate the kinematic, kinetic, and electromyographic pattern before, during and after downward squatting when the trunk movement is restricted in the sagittal plane. Eight healthy subjects performed downward squatting at two different positions, semisquatting (40°knee flexion) and half squatting (70°knee flexion). Electromyographic responses of the vastus medialis oblique, vastus medialis longus, rectus femoris, vastus lateralis, biceps femoris, semitendineous, gastrocnemius lateralis, and tibialis anterior were recorded. The kinematics of the major joints were reconstructed using an optoelectronic system. The center of pressure (COP) was obtained using data collected from one force plate, and the ankle and knee joint torques were calculated using inverse dynamics. In the upright position there were small changes in the COP and in the knee and ankle joint torques. The tibialis anterior provoked the disruption of this upright position initiating the squat. During the acceleration phase of the squat the COP moved posteriorly, the knee joint torque remained in flexion and there was no measurable muscle activation. As the body went into the deceleration phase, the knee joint torque increased towards extension with major muscle activities being observed in the four heads of the quadriceps. Understanding these kinematic, kinetic and EMG strategies before, during and after the squat is expected to be beneficial to practitioners for utilizing squatting as a task for improving motor function.
Kinematic and EMG Comparison Between Variations of Unilateral Squats Under Different Stabilities
Sports Medicine International Open, 2020
The purpose of the study was to compare kinematics and muscle activity between two variations of unilateral squats under different stability conditions. Twelve male volunteers (age: 23±5 years, mass: 80±17 kg, height: 1.81±0.11 m, strength-training experience: 4.3±1.9 years) performed four repetitions with the same external load (≈4RM). Two variations (with the non-stance leg forwards vs. backwards) were performed in a Smith-machine and free-weight condition. The variables were barbell velocity, lifting time and surface electromyography activity of the lower extremity and trunk muscles during the descending and ascending phase. The main findings were 1) peak force was higher when performing the unilateral squats in the Smith machine; 2) peak ascending barbell velocity increased from repetition 3–4 with free weight; and 3) muscle activity from the rectus femoris, vastus lateral, biceps femoris, gluteus medius, and erector spinae increased with repetitions, whereas gluteus, and medial...
Baltic Journal of Health and Physical Activity, 2018
Background: Bipedal leg squat is a common rehabilitation exercise. It is used for evaluation of lower limb function and pelvis and core stability. The aim of this study was a comparison of the lower limb, pelvis and spine ranges of motion in subjects with different declared physical activity level during bipedal squat. Material and methods: Twenty healthy student-volunteers took part in this investigation. Based on the author's questionnaire, they were divided into two groups: "higher" and "lower" physical activity level. Participants performed a two-leg squat with maximal depth, and returned to the standing position. The tridimensional motion of the ankle, knee, hip, pelvis and spine was analysed. Results: During a bipedal squat the more active subjects demonstrate a greater ankle range of motion (42.585 deg) and smaller pelvis (17.293 deg) and spine (40.228 deg) mobility in the sagittal plane than the less active participants (33.819 deg, 29.178 deg and 63.279 deg respectively). The more active group demonstrate a decreased motion of the ankle in the frontal plane (4.173 deg; 10.839 deg, p = 0.006) and an increased motion of the hip in the transverse plane (39.765deg; 27.971 deg, p = 0.035) than less the active one. Conclusions: The level of activity can lead to different movement patterns during multi-joint exercises.
Kinematic and EMG activities during front and back squat variations in maximum loads
Journal of Sports Sciences, 2015
The aim of this study was to compare the musculature activity and kinematics of knee and hip joints during front and back squat with maximal loading. Two-dimensional kinematical data were collected and electromyographic activities of vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus and erector spinae were measured while participants (n = 12, 21.2 ± 1.9 years old) were completing front and back squat exercises with maximum loading. Paired sample t-test was used for comparisons between two techniques. Results showed that the electromyographic activity of vastus medialis was found to be greater in the front squat compared to the back squat during the ascending phase (P < 0.05, d = 0.62; 95% CI, −15.0/−4.17) and the whole manoeuvre (P < 0.05, d = 0.41; 95% CI, −12.8/−0.43), while semitendinosus (P < 0.05, d = −0.79; 95% CI, 0.62/20.59) electromyographic activity was greater in the back squat during the ascending phase. Compared to the front squat version, back squat exhibited significantly greater trunk lean, with no differences occurring in the knee joint kinematics throughout the movement. Results may suggest that the front squat may be preferred to the back squat for knee extensor development and for preventing possible lumbar injuries during maximum loading.
Kinesiology Corner: Analysis of the Squat
National Strength Coaches Association Journal, 1981
The aim of this study was to perform an electromyography comparison of three commonly used lower limb injury prevention exercises: a single-leg squat on a bench (SLSB), a double-leg squat (DLS) and a double-leg squat on a BOSU® balance trainer (DLSB). After determining the maximum isometric voluntary contraction of the hamstring and quadriceps, eight female athletes performed 3 repetitions of each exercise, while electromyography activity of the biceps femoris (BF), semitendinosus (ST), vastus lateralis (VL) and vastus medialis (VM) was monitored. Comparisons between exercises revealed higher activation in BF
Journal of Human Kinetics, 2016
Bilateral decline squatting has been well documented as a rehabilitation exercise, however, little information exists on the optimum angle of decline. The aim of this study was to determine the ankle and knee angle, moments, the patellofemoral joint load, patellar tendon load and associated muscle activity while performing a double limb squat at different decline angles and the implications to rehabilitation. Eighteen healthy subjects performed double limb squats at 6 angles of declination: 0, 5, 10, 15, 20 and 25 degrees. The range of motion of the knee and ankle joints, external moments, the patellofemoral/patellar tendon load and integrated EMG of gastrocnemius, tibialis anterior, rectus femoris and biceps femoris were evaluated. As the decline angle increased up to 20 degrees, the range of motion possible at the ankle and knee increased. The joint moments showed a decrease at the ankle up to 15 degrees and an increase at the knee up to 25 degrees, indicating a progressive reduct...
Journal of sport rehabilitation, 2010
To compare EMG activity of selected hip and knee muscle groups in female athletes performing a modified single-leg squat and the 2-leg squat using the same relative intensity. Eleven Division I female athletes from a variety of sports (soccer, softball, and track) completed the study. EMG measurements were taken as the subjects completed 3 parallel repetitions at 85% of their 3-repetition maximum on each exercise. Mean and mean peak EMG data from the gluteus medius, hamstrings, and quadriceps and the quadriceps:hamstrings EMG ratio were compared between the 2 exercises. Statistically higher mean (P < .01) and mean peak (P < .05) gluteus medius and mean and mean peak (P < .01) hamstring EMG activity occurred during the modified single-leg squat. The 2-leg squat produced higher mean and mean peak (P < .05) quadriceps activity and a higher quadriceps:hamstrings EMG ratio (P < .01). Muscle-recruitment patterns appear to differ between the 2 types of squat exercises when p...
The Effect of Back Squat Depth on the EMG Activity of 4 Superficial Hip and Thigh Muscles
Journal of Strength and Conditioning Research, 2002
The purpose of this study was to measure the relative contributions of 4 hip and thigh muscles while performing squats at 3 depths. Ten experienced lifters performed randomized trials of squats at partial, parallel, and full depths, using 100-125% of body weight as resistance. Electromyographic (EMG) surface electrodes were placed on the vastus medialis (VMO), the vastus lateralis, (VL), the biceps femoris (BF), and the gluteus maximus (GM). EMG data were quantified by integration and expressed as a percentage of the total electrical activity of the 4 muscles. Analysis of variance (ANOVA) and Tukey post hoc tests indicated a significant difference (p Ͻ 0.001*, p ϭ 0.056**) in the relative contribution of the GM during the concentric phases among the partial-(16.9%*), parallel-(28.0%**), and full-depth (35.4%*) squats. There were no significant differences between the relative contributions of the BF, the VMO, and the VL at different squatting depths during this phase. The results suggest that the GM, rather than the BF, the VMO, or the VL, becomes more active in concentric contraction as squat depth increases. The effect of back squat depth on the EMG activity of 4 superficial hip and thigh muscles.
Journal of Strength and Conditioning Research, 2012
Mauntel, TC, Begalle, RL, Cram, TR, Frank, BS, Hirth, CJ, Blackburn, T, and Padua, DA. The effects of lower extremity muscle activation and passive range of motion on single leg squat performance. J Strength Cond Res 27 : 1813-1823, 2013-Knee valgus is a potential risk factor for lower extremity (LE) injuries. Clinical movement screenings and passive range of motion (PROM) measurements may help identify neuromuscular patterns, which contribute to knee valgus. The purpose of this study was to compare LE muscle activation and PROM between subjects who display visual medial knee displacement (MKD) during a single leg squat (SLS) and those who do not. We hypothesized that muscular activation and PROM would differ between the groups. Forty physically active adults (20 controls, 20 MKDs) participated in this study. Subjects completed 10 LE PROM assessments and performed 5 SLS trials while electromyography (EMG) data were collected from 8 LE muscles. Three separate multivariate analysis of variance were used to identify group differences in EMG data, muscle coactivation, and PROM. Results during the SLS indicated hip coactivation ratios revealed smaller gluteus medius to hip adductor (GMed:Hip Add) (p = 0.028) and gluteus maximus to hip adductor (GMax:Hip Add) coactivation ratios (p = 0.007) compared with the control group. Also, the MKD group displayed significantly less passive ankle dorsiflexion with the knee extended (p = 0.047) and flexed (p = 0.034), and greater talar glide motion (p = 0.012). The findings of this study indicate that MKD during a SLS seems to be influenced by decreased coactivation of the gluteal to the hip adductor muscles and restricted dorsiflexion. Therefore, conditioning, rehabilitation, and injury prevention programs should focus on decreasing hip adductor activity, increasing hip abductor and external rotator activity, and increasing ankle dorsiflexion in hopes to decrease the incidence of these injuries.