PMID- 11404665
OWN - NLM
STAT- MEDLINE
DCOM- 20010823
LR  - 20220318
IS  - 0195-9131 (Print)
IS  - 0195-9131 (Linking)
VI  - 33
IP  - 6
DP  - 2001 Jun
TI  - A three-dimensional biomechanical analysis of the squat during varying stance 
      widths.
PG  - 984-98
AB  - PURPOSE: The purpose of this study was to quantify biomechanical parameters 
      employing two-dimensional (2-D) and three-dimensional (3-D) analyses while 
      performing the squat with varying stance widths. METHODS: Two 60-Hz cameras 
      recorded 39 lifters during a national powerlifting championship. Stance width was 
      normalized by shoulder width (SW), and three stance groups were defined: 1) 
      narrow stance squat (NS), 107 +/- 10% SW; 2) medium stance squat (MS), 142 +/- 
      12% SW; and 3) wide stance squat (WS), 169 +/- 12% SW. RESULTS: Most 
      biomechanical differences among the three stance groups and between 2-D and 3-D 
      analyses occurred between the NS and WS. Compared with the NS at 45 degrees and 
      90 degrees knee flexion angle (KF), the hips flexed 6-11 degrees more and the 
      thighs were 7-12 degrees more horizontal during the MS and WS. Compared with the 
      NS at 90 degrees and maximum KF, the shanks were 5-9 degrees more vertical and 
      the feet were turned out 6 degrees more during the WS. No significant differences 
      occurred in trunk positions. Hip and thigh angles were 3-13 degrees less in 2-D 
      compared with 3-D analyses. Ankle plantar flexor (10-51 N.m), knee extensor 
      (359-573 N.m), and hip extensor (275-577 N.m) net muscle moments were generated 
      for the NS, whereas ankle dorsiflexor (34-284 N.m), knee extensor (447-756 N.m), 
      and hip extensor (382-628 N.m) net muscle moments were generated for the MS and 
      WS. Significant differences in ankle and knee moment arms between 2-D and 3-D 
      analyses were 7-9 cm during the NS, 12-14 cm during the MS, and 16-18 cm during 
      the WS. CONCLUSIONS: Ankle plantar flexor net muscle moments were generated 
      during the NS, ankle dorsiflexor net muscle moments were produced during the MS 
      and WS, and knee and hip moments were greater during the WS compared with the NS. 
      A 3-D biomechanical analysis of the squat is more accurate than a 2-D 
      biomechanical analysis, especially during the WS.
FAU - Escamilla, R F
AU  - Escamilla RF
AD  - Michael W. Krzyzewski Human Performance Laboratory, Division of Orthopaedic 
      Surgery, Duke University Medical Center, Durham, NC 27710, USA. rescamil@duke.edu
FAU - Fleisig, G S
AU  - Fleisig GS
FAU - Lowry, T M
AU  - Lowry TM
FAU - Barrentine, S W
AU  - Barrentine SW
FAU - Andrews, J R
AU  - Andrews JR
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Med Sci Sports Exerc
JT  - Medicine and science in sports and exercise
JID - 8005433
SB  - IM
MH  - Adult
MH  - Biomechanical Phenomena
MH  - Humans
MH  - Joints/physiology
MH  - Kinetics
MH  - Male
MH  - Middle Aged
MH  - Muscle Contraction/*physiology
MH  - Muscle, Skeletal/*physiology
MH  - *Posture
MH  - Weight Lifting/*physiology
EDAT- 2001/06/19 10:00
MHDA- 2001/08/24 10:01
CRDT- 2001/06/19 10:00
PHST- 2001/06/19 10:00 [pubmed]
PHST- 2001/08/24 10:01 [medline]
PHST- 2001/06/19 10:00 [entrez]
AID - 10.1097/00005768-200106000-00019 [doi]
PST - ppublish
SO  - Med Sci Sports Exerc. 2001 Jun;33(6):984-98. doi: 
      10.1097/00005768-200106000-00019.