Modelling Muscle Force Distributions During the Front and Back Squat in Trained Lifters

Abstract Various simulation type tools and conventional algorithms are being used to determine knee muscle forces of human during dynamic movement. These all may be good for clinical uses, but have some drawbacks, such as higher computational times, muscle redundancy and less cost-effective solution. Recently, there has been an interest to develop supervised learning-based prediction model for the computationally demanding process. The present research work is used to develop a cost-effective and efficient machine learning (ML) based models to predict knee muscle force for clinical interventions for the given input parameter like height, mass and angle. A dataset of 500 human musculoskeletal, have been trained and tested using four different ML models to predict knee muscle force. This dataset has obtained from anybody modeling software using AnyPyTools, where human musculoskeletal has been utilized to perform squatting movement during inverse dynamic analysis. The result based on the datasets predicts that the random forest ML model outperforms than the other selected models: neural network, generalized linear model, decision tree in terms of mean square error (MSE), coefficient of determination (R2), and Correlation (r). The MSE of predicted vs actual muscle forces obtained from the random forest model for Biceps Femoris, Rectus Femoris, Vastus Medialis, Vastus Lateralis are 19.92, 9.06, 5.97, 5.46, Correlation are 0.94, 0.92, 0.92, 0.94 and R2 are 0.88, 0.84, 0.84 and 0.89 for the test dataset, respectively.

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Differences in strength and landing biomechanics between female jumpers and swimmers

Isokinetics and Exercise Science ◽

10.3233/ies-210149 ◽

2021 ◽

pp. 1-11

Author(s):

Mianfang Ruan ◽

Qiang Zhang ◽

Xin Zhang ◽

Jing Hu ◽

Xie Wu

Keyword(s):

Muscle Force ◽

Female Athletes ◽

Young Female ◽

Single Component ◽

Plyometric Training ◽

Isokinetic Testing ◽

Female College ◽

Landing Biomechanics ◽

Drop Landing ◽

Landing Mechanics

BACKGROUND: It remains unclear if plyometric training as a single component could improve landing mechanics that are potentially associated with lower risk of ACL injury in the long term OBJECTIVE: The purpose of this study was to investigate the influence of experience undertaking plyometrics on landing biomechanics in female athletes. METHODS: Non-jumpers with little experience in plyometric training (12 female college swimmers) and jumpers with five years of experience in plyometric training (12 female college long jumpers and high jumpers) were recruited to participate in two testing sessions: an isokinetic muscle force test for the dominant leg at 120∘/s and a 40-cm drop landing test. An independent t test was applied to detect any significant effects between cohorts for selected muscle force, kinematic, kinetic, and electromyography variables. RESULTS: While female jumpers exhibited greater quadriceps eccentric strength (P= 0.013) and hamstring concentric strength (P= 0.023) during isokinetic testing than female swimmers, no significant differences were observed in kinematics, kinetics, and muscle activities during both drop landing and drop jumping. CONCLUSIONS: The results suggest that the female jumpers did not present any training-induced modification in landing mechanics regarding reducing injury risks compared with the swimmers. The current study revealed that plyometric training as a single component may not guarantee the development of low-risk landing mechanics for young female athletes.

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Eccentric Force-Velocity Characteristics during a Novel Squat Protocol in Trained Rugby Union Athletes—Pilot Study

Journal of Functional Morphology and Kinesiology ◽

10.3390/jfmk6020032 ◽

2021 ◽

Vol 6 (2) ◽

pp. 32

Author(s):

Conor McNeill ◽

C. Martyn Beaven ◽

Daniel T. McMaster ◽

Nicholas Gill

Keyword(s):

Pilot Study ◽

Dynamic Performance ◽

Intraclass Correlation ◽

Rugby Union ◽

Mean Velocity ◽

Force Development ◽

Back Squat ◽

Force Velocity ◽

Force Time ◽

Change In Mean

Eccentric strength characteristics have been shown to be important factors in physical performance. Many eccentric tests have been performed in isolation or with supramaximal loading. The purpose of this study was to investigate within- and between- session reliability of an incremental eccentric back squat protocol. Force plates and a linear position transducer captured force-time-displacement data across six loading conditions, separated by at least seven days. The reliability of eccentric specific measurements was assessed using coefficient of variation (CV), change in mean, and intraclass correlation coefficient (ICC). Eccentric peak force demonstrated good ICC (≥0.82) and TE (≤7.3%) for each load. Variables based on mean data were generally less reliable (e.g., mean rate of force development, mean force, mean velocity). This novel protocol meets acceptable levels of reliability for different eccentric-specific measurements although the extent to which these variables affect dynamic performance requires further research.

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Geometrical factors influencing muscle force development. II. Radial forces

Biophysical Journal ◽

10.1016/s0006-3495(80)85077-6 ◽

1980 ◽

Vol 30 (1) ◽

pp. 69-77 ◽

Cited By ~ 30

Author(s):

M. Schoenberg

Keyword(s):

Muscle Force ◽

Force Development ◽

Factors Influencing ◽

Radial Forces ◽

Geometrical Factors

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What Happened with Muscle Force, Dynamic Stability And Falls?- a 10-Year Longitudinal Follow-Up in Adults with Myotonic Dystrophy Type 1

Journal of Neuromuscular Diseases ◽

10.3233/jnd-200521 ◽

2021 ◽

pp. 1-10

Author(s):

Elisabet Hammarén ◽

Lena Kollén

Keyword(s):

Myotonic Dystrophy ◽

Dynamic Stability ◽

Muscle Force ◽

Step Test ◽

Maximum Speed ◽

Myotonic Dystrophy Type 1 ◽

Myotonic Dystrophy Type ◽

Patient Reported ◽

Leg Muscle

Background: Individuals with myotonic dystrophy type 1 (DM1) are known to stumble and fall, but knowledge is scarce regarding dynamic stability in this disorder. Objective: To describe disease progress regarding muscle force, dynamic stability and patient reported unintentional falls during a ten-year period, in individuals with DM1. Methods: Quantification of isometric muscle force in four leg muscle groups and assessment of Timed 10-meter-walk in maximum speed (T10max), Timed Up&Go (TUG) and Step test (STEP) were performed at three occasions in a DM1 cohort, together with self-reported falls. Results: Thirty-four people (m/f:11/23, age:50.2 + /–9.4) participated. The muscle force loss after ten years was large in the distal ankle muscles. A steeper force decrease was seen in most muscles between year five and ten compared to the former five-year period. Males reported more falls than females, 91%vs 35%had fallen last year. A positive correlation, ρ= 0.633, p < 0.001, was shown between walking time (T10max) and number of falls. Frequent fallers were only seen among those with slower walk (T10max > 10seconds), and fewer steps in the STEP test (STEP≤5 steps). Conclusions: A diminishing leg muscle strength and worse dynamic stability were seen in the group, with a steeper decrease in the latter five years. Weak ankle dorsiflexors, a slower walk and difficulties to lift the forefoot were related to frequent falls.

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Prediction of One Repetition Maximum Using Reference Minimum Velocity Threshold Values in Young and Middle-Aged Resistance-Trained Males

Behavioral Sciences ◽

10.3390/bs11050071 ◽

2021 ◽

Vol 11 (5) ◽

pp. 71

Author(s):

John F. T. Fernandes ◽

Amelia F. Dingley ◽

Amador Garcia-Ramos ◽

Alejandro Perez-Castilla ◽

James J. Tufano ◽

...

Keyword(s):

Bench Press ◽

Absolute Error ◽

Young Group ◽

Middle Aged ◽

Repetition Maximum ◽

Back Squat ◽

Velocity Threshold ◽

Low Load ◽

The Absolute ◽

Minimum Velocity

Background: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. Methods: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20–80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. Results: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. Conclusion: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.

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Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

The American Journal of Sports Medicine ◽

10.1177/0363546520988039 ◽

2021 ◽

Vol 49 (4) ◽

pp. 994-1004

Author(s):

Andreas Martin Seitz ◽

Florian Schall ◽

Steffen Paul Hacker ◽

Stefan van Drongelen ◽

Sebastian Wolf ◽

...

Keyword(s):

Knee Flexion ◽

Muscle Force ◽

Meniscal Tear ◽

In Vitro Tests ◽

Jump Landing ◽

Medial Meniscectomy ◽

Attachment Structures ◽

Flexion Extension ◽

Longitudinal Tear

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% ( P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces ( P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced ( P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

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