{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/86424"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/86424","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Estimating Lumbar Spinal Loads During a Golf Swing Using an EMG -Assisted Optimization Model Approach","abstract":"The purpose of this study was to estimate the lumbar spinal loads at L4--L5 level during a golf swing using musculoskeletal modeling techniques. This study also examined the activation patterns of individual lower trunk muscles during a golf swing using surface electromyographic (EMG) techniques. Data were collected from five college golfers (average handicap = 0.8, SD = 1.1). Four S-VHS camcorders and two force plates were used to obtain the 3-D kinetics and kinematics of the lower trunk. The EMG-assisted and EMG-assisted optimization models were used to estimate lower trunk muscle forces. The major findings of this study were that (a) the compressive load increased steadily after the end of backswing (EB) and reached its maximum of 605% body weight during the acceleration phase, and the mean peak compressive load of 4,300 N was recorded near the instant of the ball/driver impact; (b) the mean antero-posterior (A/P) shear load increased gradually after EB and reached its peak (882 N) at around the middle of follow-through (MF); (c) the mean medio-lateral (M/L) shear load was mostly acting toward the right during the take away phase and the direction was reversed sometime during the early downswing and reached its peak (-252 N) around MF; and (d) the timing and pattern of the lumbar spinal forces obtained in this study are very different from the corresponding forces reported in the literature. The results demonstrate that the L4--L5 motion segment is subjected to considerable compressive, A/P shear, and M/L shear loads during a golf swing. The repetitive changing direction of the shear load during a golf swing may cause the fatigue fracture of pars interarticularis. The results also suggest that a golf swing with reduced backswing and follow-through may alleviate the risk of back injury. This alternative swing pattern limits the range of motion of the trunk and, consequently, reduces passive tensions of the lower trunk muscles and lumbar spinal loads.","abstract_html":"The purpose of this study was to estimate the lumbar spinal loads at L4--L5 level during a golf swing using musculoskeletal modeling techniques. This study also examined the activation patterns of individual lower trunk muscles during a golf swing using surface electromyographic (EMG) techniques. Data were collected from five college golfers (average handicap = 0.8, SD = 1.1). Four S-VHS camcorders and two force plates were used to obtain the 3-D kinetics and kinematics of the lower trunk. The EMG-assisted and EMG-assisted optimization models were used to estimate lower trunk muscle forces. The major findings of this study were that (a) the compressive load increased steadily after the end of backswing (EB) and reached its maximum of 605% body weight during the acceleration phase, and the mean peak compressive load of 4,300 N was recorded near the instant of the ball/driver impact; (b) the mean antero-posterior (A/P) shear load increased gradually after EB and reached its peak (882 N) at around the middle of follow-through (MF); (c) the mean medio-lateral (M/L) shear load was mostly acting toward the right during the take away phase and the direction was reversed sometime during the early downswing and reached its peak (-252 N) around MF; and (d) the timing and pattern of the lumbar spinal forces obtained in this study are very different from the corresponding forces reported in the literature. The results demonstrate that the L4--L5 motion segment is subjected to considerable compressive, A/P shear, and M/L shear loads during a golf swing. The repetitive changing direction of the shear load during a golf swing may cause the fatigue fracture of pars interarticularis. The results also suggest that a golf swing with reduced backswing and follow-through may alleviate the risk of back injury. This alternative swing pattern limits the range of motion of the trunk and, consequently, reduces passive tensions of the lower trunk muscles and lumbar spinal loads.","abstract_has_math":false,"creators":["Lim, Young-Tae"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Kinesiology and Community Health","degree_department":null,"school":null,"contributors":["John W. Chow"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T15:04:33Z","date_published":"2015-09-28T15:04:33Z","updated_at":"2026-07-22T22:26:27Z","subjects":["Applied Mechanics"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9955642"],"render_values":[{"text":"(MiAaPQ)AAI9955642","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/86424","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["John W. 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This study also examined the activation patterns of individual lower trunk muscles during a golf swing using surface electromyographic (EMG) techniques. Data were collected from five college golfers (average handicap = 0.8, SD = 1.1). Four S-VHS camcorders and two force plates were used to obtain the 3-D kinetics and kinematics of the lower trunk. The EMG-assisted and EMG-assisted optimization models were used to estimate lower trunk muscle forces. The major findings of this study were that (a) the compressive load increased steadily after the end of backswing (EB) and reached its maximum of 605% body weight during the acceleration phase, and the mean peak compressive load of 4,300 N was recorded near the instant of the ball/driver impact; (b) the mean antero-posterior (A/P) shear load increased gradually after EB and reached its peak (882 N) at around the middle of follow-through (MF); (c) the mean medio-lateral (M/L) shear load was mostly acting toward the right during the take away phase and the direction was reversed sometime during the early downswing and reached its peak (-252 N) around MF; and (d) the timing and pattern of the lumbar spinal forces obtained in this study are very different from the corresponding forces reported in the literature. The results demonstrate that the L4--L5 motion segment is subjected to considerable compressive, A/P shear, and M/L shear loads during a golf swing. The repetitive changing direction of the shear load during a golf swing may cause the fatigue fracture of pars interarticularis. The results also suggest that a golf swing with reduced backswing and follow-through may alleviate the risk of back injury. This alternative swing pattern limits the range of motion of the trunk and, consequently, reduces passive tensions of the lower trunk muscles and lumbar spinal loads.","Made available in DSpace on 2015-09-28T15:04:33Z (GMT). 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This study also examined the activation patterns of individual lower trunk muscles during a golf swing using surface electromyographic (EMG) techniques. Data were collected from five college golfers (average handicap = 0.8, SD = 1.1). Four S-VHS camcorders and two force plates were used to obtain the 3-D kinetics and kinematics of the lower trunk. The EMG-assisted and EMG-assisted optimization models were used to estimate lower trunk muscle forces. The major findings of this study were that (a) the compressive load increased steadily after the end of backswing (EB) and reached its maximum of 605% body weight during the acceleration phase, and the mean peak compressive load of 4,300 N was recorded near the instant of the ball/driver impact; (b) the mean antero-posterior (A/P) shear load increased gradually after EB and reached its peak (882 N) at around the middle of follow-through (MF); (c) the mean medio-lateral (M/L) shear load was mostly acting toward the right during the take away phase and the direction was reversed sometime during the early downswing and reached its peak (-252 N) around MF; and (d) the timing and pattern of the lumbar spinal forces obtained in this study are very different from the corresponding forces reported in the literature. The results demonstrate that the L4--L5 motion segment is subjected to considerable compressive, A/P shear, and M/L shear loads during a golf swing. The repetitive changing direction of the shear load during a golf swing may cause the fatigue fracture of pars interarticularis. The results also suggest that a golf swing with reduced backswing and follow-through may alleviate the risk of back injury. This alternative swing pattern limits the range of motion of the trunk and, consequently, reduces passive tensions of the lower trunk muscles and lumbar spinal loads.","Made available in DSpace on 2015-09-28T15:04:33Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9955642.pdf: 8550758 bytes, checksum: e1a91f93d7f355b2b6253bcf24ebce94 (MD5) Previous issue date: 2000","Embargo set by: Seth Robbins for item 87705 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","222 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2000."],"dc:identifier":["http://hdl.handle.net/2142/86424","(MiAaPQ)AAI9955642"],"dc:language":["eng"],"dc:subject":["Applied Mechanics"],"dc:title":["Estimating Lumbar Spinal Loads During a Golf Swing Using an EMG -Assisted Optimization Model Approach"],"dc:type":["text"],"thesis:degree_discipline":["Kinesiology and Community Health"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:27Z"}