Exercise Science Commons^™

A Biomechanical Analysis Of Back Squats: Motion Capture, Electromyography, And Musculoskeletal Modeling, Eva Maria Urdiales Maddox

Human Movement Studies & Special Education Theses & Dissertations

Previous literature evaluating maximal back squats have failed to identify key components of the study decisions and procedures that would allow for duplication. Firstly, the existence of a sticking region in maximally weighted resistance exercises is frequently discussed and has been described as a force-reduced transition phase between an acceleration phase and a strength phase of a lift. However, the etiology has yet to be agreed upon. Second, Electromyography (EMG) is frequently used to assess muscle activations. However, no best practice for EMG normalization has been proposed. Two methods are commonly implemented for normalizing EMG: a maximum voluntary isometric contraction …

Evidence For The Use Of Dynamic Maximum Normalization Method Of Muscle Activation During Weight Back Squats, Eva Maddox, Hunter J. Bennett

College of Education & Professional Studies (Darden) Posters

The purpose of this study was to evaluate intra and inter-participant variability and reliability of muscle activations when analyzed using maximum voluntary isometric contractions (MVIC) and dynamic maximum (DMVC) normalization methods. Muscle activations were collected on twenty-seven participants (13 females, 14 males) performing one-repetition maximum (1RM) and submaximum (80%) back squats. Data from submaximum squats were normalized to MVICs and DMVCs. Data were compared using intra-class correlations over two testing days, variance ratio, and coefficients of variation. Mixed-model ANOVAs were used to elucidate the influence on intra- (method) and inter- (sex) subject variability. Reliability levels were good for rectus femoris …

Lower Extremity Biomechanics In Individuals With And Without Previous Hamstring Injury, Jessica A. Mutchler

Human Movement Studies & Special Education Theses & Dissertations

Primary risk factors for hamstrings strains such as fatigue, previous injury and strength deficits have been identified in the research, yet re-injury rates remain high among the physically active. Sub-acute analysis of the hip, knee and ankle biomechanics following a hamstrings strain have been largely overlooked and may provide additional insight into re-injury risks. It was the aim of this dissertation to explore long-term adaptations in walking and running tasks following a hamstrings strain, and to develop a hip endurance test that could be used in future studies.

Project one used a cross-sectional study with test-retest design to develop and …

Peroneal Reaction Time After Ankle Sprain: A Systematic Review And Meta-Analysis, Matthew C. Hoch, Patrick O. Mckeon

Human Movement Studies & Special Education Faculty Publications

Background: Many studies have examined the temporal response of the peroneal muscles to sudden inversion perturbation in patients with a previous ankle sprain. The purpose of this systematic review with meta-analysis was to synthesize the evidence and determine whether peroneal reaction time (PRT) impairments are present after ankle sprain. Methods: An electronic search was conducted using PubMed Central and EBSCOhost (1965-January 2013). Articles were included if they 1) examined the PRT to sudden inversion perturbation in patients with a history of ankle sprain using a mechanical tilt platform, 2) made comparisons with a control group or contralateral limb with no …

Emg Analysis Of Core And Thigh Musculature Contribution During Double And Single Leg Squats On Both Stable And Unstable Surfaces, Julie M. Whitehead

Human Movement Studies & Special Education Theses & Dissertations

The purpose of this study was to determine EMG activity of the hip stabilizers, thigh, and core muscles during various squatting exercises in order to better appreciate the contribution of the core and thigh during weight bearing functional activity. Surface EMG electrodes were placed over the rectus abdominis (RA), internal oblique (IO), external oblique (EO), erector spinae (ES), vastus medialis (VM), biceps femoris (BF), and gluteus medius (GM). The right leg was used for any single leg exercises perforn1ed. Each subject performed three double leg and three single leg un-weighted squats to 60 degrees of knee flexion on a stable …

Comparison Of The Emg Activity Of The Supraspinatus And Infraspinatus Muscles During Various Closed Chain Exercises, I-Chen Lin

Rehabilitation Sciences Theses & Dissertations

Advantages of closed chain exercises used in the lower extremity have been well documented. However, the effects of closed chain exercises on the upper extremities have not been studied very much. Thus, the purpose of this research is to analyze the EMG activity of the supraspinatus and infraspinatus muscles and compare the relative amounts of activities by performing different isotonic closed chain exercises and an open chain exercise in normal subjects. The supraspinatus and infraspinatus muscles in 1 o healthy subjects were studied with fine wire, intramuscular, electromyographic electrodes while performing 5 closed chain exercises and a D2. open chain …