The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat

# Background Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clea...

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Main Authors: Joseph B. McCormick, Alexander S. Drusch, Darragh J. Lynch, Gesine H. Seeber, Katherine F. Wilford, Troy L. Hooper, Brad S. Allen, Dennis G. O’Connell, Maria J. Mena-Iturriaga, Kinyata J. Cooper, Phillip S. Sizer
Format: Article
Language:English
Published: North American Sports Medicine Institute 2023-08-01
Series:International Journal of Sports Physical Therapy
Online Access:https://doi.org/10.26603/001c.84306
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author Joseph B. McCormick
Alexander S. Drusch
Darragh J. Lynch
Gesine H. Seeber
Katherine F. Wilford
Troy L. Hooper
Brad S. Allen
Dennis G. O’Connell
Maria J. Mena-Iturriaga
Kinyata J. Cooper
Phillip S. Sizer
author_facet Joseph B. McCormick
Alexander S. Drusch
Darragh J. Lynch
Gesine H. Seeber
Katherine F. Wilford
Troy L. Hooper
Brad S. Allen
Dennis G. O’Connell
Maria J. Mena-Iturriaga
Kinyata J. Cooper
Phillip S. Sizer
author_sort Joseph B. McCormick
collection DOAJ
description # Background Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation. # Hypothesis/Purpose The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects. # Study Design Controlled Laboratory Study # Methods Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey's Post-Hoc tests identified the location of significant differences. # Results Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p\<0.001, ICL: p\<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine. # Conclusions Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs. # Level of Evidence Level 3
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spelling doaj-art-cccdfa961f734b93acb88ea9936bef082025-02-11T20:27:21ZengNorth American Sports Medicine InstituteInternational Journal of Sports Physical Therapy2159-28962023-08-01184The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell SquatJoseph B. McCormickAlexander S. DruschDarragh J. LynchGesine H. SeeberKatherine F. WilfordTroy L. HooperBrad S. AllenDennis G. O’ConnellMaria J. Mena-IturriagaKinyata J. CooperPhillip S. Sizer# Background Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation. # Hypothesis/Purpose The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects. # Study Design Controlled Laboratory Study # Methods Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey's Post-Hoc tests identified the location of significant differences. # Results Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p\<0.001, ICL: p\<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine. # Conclusions Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs. # Level of Evidence Level 3https://doi.org/10.26603/001c.84306
spellingShingle Joseph B. McCormick
Alexander S. Drusch
Darragh J. Lynch
Gesine H. Seeber
Katherine F. Wilford
Troy L. Hooper
Brad S. Allen
Dennis G. O’Connell
Maria J. Mena-Iturriaga
Kinyata J. Cooper
Phillip S. Sizer
The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
International Journal of Sports Physical Therapy
title The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
title_full The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
title_fullStr The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
title_full_unstemmed The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
title_short The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat
title_sort effect of volitional preemptive abdominal contraction on biomechanical measures during a front versus back loaded barbell squat
url https://doi.org/10.26603/001c.84306
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