Browsing by Author "Goodman, William Wesley"

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An induced acceleration analysis of the barbell back squat
(Montana State University - Bozeman, College of Education, Health & Human Development, 2024) Goodman, William Wesley; Chairperson, Graduate Committee: Dawn Tarabochia; This is a manuscript style paper that includes co-authored chapters.
The barbell squat exercise is performed in settings ranging from rehabilitation through to developing muscle size, strength and power. Unfortunately, the lower extremity coordination producing the squat is not clearly understood. This thesis involves three studies evaluating how lower limb joints and muscles coordinate varied squat performance. Study one-three included 13 females who performed squats at three randomized depths (above parallel, parallel, below parallel) using 85% of their 1 repetition maximum at each respective depth. In study one, performance was evaluated by estimating the individual muscle force production and the individual muscle contribution to whole body acceleration using a musculoskeletal model. In study two, performance was evaluated by estimating the individual muscle force production and the individual muscle contribution to the lower body joint accelerations using a musculoskeletal model. In study three, knee joint contact loads were estimated using an advanced musculoskeletal model. Because muscles can accelerate all joints in the body, including a joint that it does not span, musculoskeletal models are necessary to determine muscle function. Varied coordination indicates that depth and load specificity is important and should be taken into consideration when programming based on the status and goals of the individual.
Support moment distribution and induced acceleration analysis of the barbell back squat
(Montana State University - Bozeman, College of Education, Health & Human Development, 2020) Goodman, William Wesley; Chairperson, Graduate Committee: David Graham and James P. Becker (co-chair); Victoria Flores, Joshua Cotter, David Graham and James Becker were co-authors of the article, 'Support moment distribution during the barbell back squat at different depths and loads in recreationally trained females' submitted to the journal 'Journal of strength and conditioning research' which is contained within this thesis.; James Becker and David Graham were co-authors of the article, 'An induced acceleration analysis of the barbell back squat at different depths in trained females' submitted to the journal 'Journal of strength and conditioning research' which is contained within this thesis.
The barbell squat exercise is performed in settings ranging from rehabilitation through to developing muscle size, strength and power. Unfortunately, the lower extremity coordination producing the squat is not clearly understood. This thesis involves two studies evaluating how lower limb joints and muscles coordinate varied squat performance. Study one included 19 females who performed squats at three randomized depths (above parallel, parallel, below parallel) and three loads (unloaded, 50%, 85% 1 repetition maximum). Inverse dynamics analysis revealed that peak hip and ankle extensor moments varied with load but not depth and were greatest when using 85% 1 repetition maximum. Within each depth, as load increased so did peak knee extensor moments. Peak knee extensor moments were greatest when squatting below parallel with load. Within each depth as load increased contribution of the hip increased whereas the knee decreased. Ankle contribution was only influenced by load. When squatting to deep depths with load, the contribution of the hip decreased while the knee increased. In study two, 13 females squatted to the same 3 depths using 85% of their 1 repetition maximum at each respective depth. Performance was evaluated by estimating the individual muscle force production and the individual muscle contribution to whole body acceleration using a musculoskeletal model. The gluteus maximus and adductors increased peak force to parallel while the hamstrings and rectus femoris increased to below parallel. At deep depths, the vasti decreased peak force while the hamstrings and rectus femoris increased peak force. The induced acceleration of the vasti at transition decreased with depth while the hamstrings and rectus femoris increased. Because muscles can instantaneously accelerate all joints in the body, it's possible that at transition the hamstrings accelerated the hip and knee into extension while the rectus femoris also accelerated the knee and hip into extension while the soleus accelerated the ankle and knee into extension. In conclusion, a complex coordination of the lower extremity is used performing the squat. Varied coordination indicates that depth and load specificity is important and should be taken into consideration when programming based on the status and goals of the individual.