Joint-Level Analyses of the Back Squat With and Without Intraset Rest

2019 ◽  
Vol 14 (5) ◽  
pp. 583-589 ◽  
Author(s):  
Jason D. Stone ◽  
Adam C. King ◽  
Shiho Goto ◽  
John D. Mata ◽  
Joseph Hannon ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Movement Pattern ◽  
Joint Angles ◽  
Mean Power ◽  
Joint Power ◽  
Joint Level ◽  
Back Squat ◽  
Squat Exercise ◽  
Limb Kinematics ◽  
Plane Joint

Purpose: To provide a joint-level analysis of traditional (TS) and cluster (CS) set structure during the back-squat exercise. Methods: Eight men (24 [3] y, 177.3 [7.9] cm, 82.7 [11.0] kg, 11.9 [3.5] % body fat, and 150.3 [23.0] kg 1-repetition maximum [1RM]) performed the back-squat exercise (80%1RM) using TS (4 × 6, 2-min interset rest) and CS (4 × [2 × 3], 30-s intraset rest, 90-s interset rest), randomly. Lower-limb kinematics were collected by motion capture, as well as kinetic data by bilateral force platforms. Results: CS attenuated the loss in mean power (TS −21.6% [3.9%]; CS −12.4% [7.5%]; P = .042), although no differences in gross movement pattern (sagittal-plane joint angles) within and between conditions were observed (P ≥ .05). However, joint power produced at the hip increased from repetition (REP) 1 through REP 6 during TS, while a decrease was noted at the knee. A similar pattern was observed in the CS condition but was limited to the hip. Joint power produced at the hip increased from REP 1 through REP 3 but returned to REP 1 values before a similar increase through REP 6, resulting in differences between conditions (REP 4, P = .018; REP 5, P = .022). Conclusions: Sagittal-plane joint angles did not change in either condition, although CS elicited greater power. Differing joint power contributions (hip and knee) suggest potential central mechanism that may contribute to enhanced power output during CS and warrant further study. Practitioners should consider incorporating CS into training to promote greater power adaptations and to mitigate fatigue.

The Lumbar and Sacrum Movement Pattern During the Back Squat Exercise

2010 ◽  
Vol 24 (10) ◽  
pp. 2731-2741 ◽  
Author(s):  
Mark R McKean ◽  
Peter K Dunn ◽  
Brendan J. Burkett
Keyword(s):  
Movement Pattern ◽  
Back Squat ◽  
Squat Exercise

Distance running stride-to-stride variability for sagittal plane joint angles

2020 ◽  
pp. 1-15
Author(s):  
Jeff T. Wight ◽  
Jordon E. J. Garman ◽  
David R. Hooper ◽  
Christopher T. Robertson ◽  
Reed Ferber ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Distance Running ◽  
Joint Angles ◽  
Plane Joint

scholarly journals Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Paulo Henrique Marchetti ◽  
Josinaldo Jarbas da Silva ◽  
Brad Jon Schoenfeld ◽  
Priscyla Silva Monteiro Nardi ◽  
Silvio Luis Pecoraro ◽  
...  
Keyword(s):  
Knee Joint ◽  
Muscle Activation ◽  
Specific Activity ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Joint Angles ◽  
Back Squat ◽  
Squat Exercise

The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only.

scholarly journals Assessment of Back-Squat Performance at Submaximal Loads: Is the Reliability Affected by the Variable, Exercise Technique, or Repetition Criterion?

2021 ◽  
Vol 18 (9) ◽  
pp. 4626
Author(s):  
Alejandro Pérez-Castilla ◽  
Danica Janicijevic ◽  
Zeki Akyildiz ◽  
Deniz Senturk ◽  
Amador García-Ramos
Keyword(s):  
Peak Power ◽  
Peak Velocity ◽  
Average Score ◽  
Experimental Session ◽  
Mean Power ◽  
Mean Velocity ◽  
Repetition Maximum ◽  
Performance Variables ◽  
Back Squat ◽  
Squat Exercise

This study aimed to compare the between-session reliability of different performance variables during 2 variants of the Smith machine back-squat exercise. Twenty-six male wrestlers performed 5 testing sessions (a 1-repetition maximum [1RM] session, and 4 experimental sessions [2 with the pause and 2 with the rebound technique]). Each experimental session consisted of performing 3 repetitions against 5 loads (45–55–65–75–85% of the 1RM). Mean velocity (MV), mean power (MP), peak velocity (PV), and peak power (PP) variables were recorded by a linear position transducer (GymAware PowerTool). The best and average scores of the 3 repetitions were considered for statistical analyses. The coefficient of variation (CV) ranged from 3.89% (best PV score at 55% 1 RM using the pause technique) to 10.29% (average PP score at 85% 1 RM using the rebound technique). PP showed a lower reliability than MV, MP, and PV (CVratio ≥ 1.26). The reliability was comparable between the exercise techniques (CVratio = 1.08) and between the best and average scores (CVratio = 1.04). These results discourage the use of PP to assess back-squat performance at submaximal loads. The remaining variables (MV, MP, or PV), exercise techniques (pause or rebound), and repetition criteria (best score or average score) can be indistinctly used due to their acceptable and comparable reliability.

Differences Between Local and Orbital Dynamic Stability During Human Walking

2006 ◽  
Vol 129 (4) ◽  
pp. 586-593 ◽  
Author(s):  
Jonathan B. Dingwell ◽  
Hyun Gu Kang
Keyword(s):  
Gait Cycle ◽  
Sagittal Plane ◽  
Orbital Stability ◽  
Human Walking ◽  
Joint Angles ◽  
Global Instability ◽  
Small Perturbations ◽  
Floquet Multipliers ◽  
Plane Joint ◽  
Condition Interaction

Currently there is no commonly accepted way to define, much less quantify, locomotor stability. In engineering, “orbital stability” is defined using Floquet multipliers that quantify how purely periodic systems respond to perturbations discretely from one cycle to the next. For aperiodic systems, “local stability” is defined by local divergence exponents that quantify how the system responds to very small perturbations continuously in real time. Triaxial trunk accelerations and lower extremity sagittal plane joint angles were recorded from ten young healthy subjects as they walked for 10min over level ground and on a motorized treadmill at the same speed. Maximum Floquet multipliers (Max FM) were computed at each percent of the gait cycle (from 0% to 100%) for each time series to quantify the orbital stability of these movements. Analyses of variance comparing Max FM values between walking conditions and correlations between Max FM values and previously published local divergence exponent results were computed. All subjects exhibited orbitally stable walking kinematics (i.e., magnitudes of Max FM<1.0), even though these same kinematics were previously found to be locally unstable. Variations in orbital stability across the gait cycle were generally small and exhibited no systematic patterns. Walking on the treadmill led to small, but statistically significant improvements in the orbital stability of mediolateral (p=0.040) and vertical (p=0.038) trunk accelerations and ankle joint kinematics (p=0.002). However, these improvements were not exhibited by all subjects (p⩽0.012 for subject × condition interaction effects). Correlations between Max FM values and previously published local divergence exponents were inconsistent and 11 of the 12 comparisons made were not statistically significant (r2⩽19.8%; p⩾0.049). Thus, the variability inherent in human walking, which manifests itself as local instability, does not substantially adversely affect the orbital stability of walking. The results of this study will allow future efforts to gain a better understanding of where the boundaries lie between locally unstable movements that remain orbitally stable and those that lead to global instability (i.e., falling).

scholarly journals Lower Limb Kinematics Using Inertial Sensors during Locomotion: Accuracy and Reproducibility of Joint Angle Calculations with Different Sensor-to-Segment Calibrations

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 715 ◽  
Author(s):  
Julien Lebleu ◽  
Thierry Gosseye ◽  
Christine Detrembleur ◽  
Philippe Mahaudens ◽  
Olivier Cartiaux ◽  
...  
Keyword(s):  
Lower Limb ◽  
Inertial Sensors ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Human Movement ◽  
Absolute Difference ◽  
Measurement Unit ◽  
Joint Angles ◽  
3D Tracking ◽  
Limb Kinematics

Inertial measurement unit (IMU) records of human movement can be converted into joint angles using a sensor-to-segment calibration, also called functional calibration. This study aims to compare the accuracy and reproducibility of four functional calibration procedures for the 3D tracking of the lower limb joint angles of young healthy individuals in gait. Three methods based on segment rotations and one on segment accelerations were used to compare IMU records with an optical system for their accuracy and reproducibility. The squat functional calibration movement, offering a low range of motion of the shank, provided the least accurate measurements. A comparable accuracy was obtained in other methods with a root mean square error below 3.6° and an absolute difference in amplitude below 3.4°. The reproducibility was excellent in the sagittal plane (intra-class correlation coefficient (ICC) > 0.91, standard error of measurement (SEM) < 1.1°), good to excellent in the transverse plane (ICC > 0.87, SEM < 1.1°), and good in the frontal plane (ICC > 0.63, SEM < 1.2°). The better accuracy for proximal joints in calibration movements using segment rotations was traded to distal joints in calibration movements using segment accelerations. These results encourage further applications of IMU systems in unconstrained rehabilitative contexts.

Functional Data Analyses for the Assessment of Joint Power Profiles During Gait of Stroke Subjects

2014 ◽  
Vol 30 (2) ◽  
pp. 348-352 ◽  
Author(s):  
André G. P. Andrade ◽  
Janaine C. Polese ◽  
Leopoldo A. Paolucci ◽  
Hans-Joachim K. Menzel ◽  
Luci F. Teixeira-Salmela
Keyword(s):  
Power Generation ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Knee Extension ◽  
Mathematical Function ◽  
Joint Power ◽  
Gait Biomechanics ◽  
Isolated Points ◽  
Parametric Analyses

Lower extremity kinetic data during walking of 12 people with chronic poststroke were reanalyzed, using functional analysis of variance (FANOVA). To perform the FANOVA, the whole curve is represented by a mathematical function, which spans the whole gait cycle and avoids the need to identify isolated points, as required for traditional parametric analyses of variance (ANOVA). The power variables at the ankle, knee, and hip joints, in the sagittal plane, were compared between two conditions: With and without walking sticks at comfortable and fast speeds. For the ankle joint, FANOVA demonstrated increases in plantar flexion power generation during 60–80% of the gait cycle between fast and comfortable speeds with the use of walking sticks. For the knee joint, the use of walking sticks resulted in increases in the knee extension power generation during 10–30% of the gait cycle. During both speeds, the use of walking sticks resulted in increased power generation by the hip extensors and flexors during 10–30% and 40–70% of the gait cycle, respectively. These findings demonstrated the benefits of applying the FANOVA approach to improve the knowledge regarding the effects of walking sticks on gait biomechanics and encourage its use within other clinical contexts.

scholarly journals Effects of front and back squat techniques on patellofemoral joint kinetics in males

2015 ◽  
Vol 2 (1) ◽  
pp. 76 ◽  
Author(s):  
J Sinclair ◽  
S Atkins ◽  
N Kudiersky ◽  
PJ Taylor ◽  
H Vincent
Keyword(s):  
Patellofemoral Joint ◽  
Pain Syndrome ◽  
Current Investigation ◽  
Strength And Conditioning ◽  
Joint Kinetics ◽  
Associated Injury ◽  
Back Squat ◽  
Squat Exercise ◽  
Experienced Male ◽  
Joint Load

Purpose: The barbell squat is fundamental in strength and conditioning, with two principal variants; the back and front squat. Unfortunately, the propensity for injury is high particularly at the knee. The aim of the current investigation was examine the influence of front and back squat variations on patellofemoral joint load. Methods: Patellofemoral loads were obtained from thirty-five experienced male participants, who completed both back and front squats at 70% of 1 RM. Differences between squat conditions were examined using Bonferroni adjusted (P = .008) paired t-tests. Results: The results showed that significant differences (P < .008) in patellofemoral load were identified between both conditions with the highest load being experienced during the back squat exercise. Conclusions: Given the proposed relationship between the magnitude of the load experienced by the patellofemoral joint and associated injury pathology, the back squat appears to place lifters at greater risk from injury. Therefore, it may be prudent therefore for lifters who are predisposed to patellofemoral pain syndrome to utilize the front squat in their training.

scholarly journals Sex-specific Effects of Localized Muscle Fatigue on Upper Body Kinematics During a Repetitive Pointing Task

2021 ◽  
Author(s):  
Chen Yang ◽  
Julie N. Côté
Keyword(s):  
Muscle Fatigue ◽  
Musculoskeletal Disorders ◽  
Movement Pattern ◽  
Upper Body ◽  
Lateral Flexion ◽  
Joint Angles ◽  
Localized Muscle Fatigue ◽  
Specific Effects ◽  
Spinal Movement ◽  
Pointing Task

Abstract BackgroundFemales are reported to have a higher risk of musculoskeletal disorders than males. Among risk factors for musculoskeletal disorders, the mechanism of muscle fatigue remains unclear. Especially how females and males adapt to localized fatigue is poorly understood. The purpose of the study was to examine the sex-specific effects of fatigue location on shoulder, elbow and spinal joint angles, and angular variabilities during a repetitive pointing task.MethodsSeven males and ten females performed a standing repetitive pointing task when they were non-fatigued (NF), elbow-fatigued (EF), shoulder-fatigued (SF) and trunk-fatigued (TF), while trunk and upper body tridimensional kinematic data was recorded. Joint angles and angular variabilities of shoulder, elbow, upper thorax, lower thorax, and lumbar were calculated. ResultsResults showed that shoulder angles changed the most after EF in males, but after SF in females. The similarities between sexes were that SF increased the variabilities at upper (lateral flexion: 0.15° greater than NF, rotation: 0.26° greater than all other conditions) and lower thorax (lateral flexion: 0.13° greater than NF, rotation: averagely 0.1° greater than all other condition) in both sexes. TF altered upper thorax variability (0.36° smaller than SF), lower thorax angle (lateral flexion: 3.00° greater than NF, rotation: 1.68° greater than SF), and lumbar angle (averagely 1.8° smaller than all other conditions) in both sexes. However, females had greater lower thorax angle (lateral flexion: 8.3° greater, p=0.005) as well as greater upper (rotation: 0.53° greater, p=0.006) and lower thorax (rotation: 0.5° greater, p=0.007; flexion: 0.6° greater, p=0.014) angular variabilities.ConclusionsThe overall greater lower and upper thorax angular variabilities suggested a more unstable spinal movement pattern in females. The kinematic differences between sexes highlighted a few sex differences in adapting the localized muscle fatigue.

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