Cargando…
Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies
BACKGROUND: Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when per...
Autores principales: | , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
SAGE Publications
2015
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4332646/ https://www.ncbi.nlm.nih.gov/pubmed/25984263 http://dx.doi.org/10.1177/1941738114565088 |
_version_ | 1782357933443514368 |
---|---|
author | Shultz, Rebecca Silder, Amy Malone, Maria Braun, Hillary Jane Dragoo, Jason Logan |
author_facet | Shultz, Rebecca Silder, Amy Malone, Maria Braun, Hillary Jane Dragoo, Jason Logan |
author_sort | Shultz, Rebecca |
collection | PubMed |
description | BACKGROUND: Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when performing a single-leg drop (SLD) on to a Bosu ball (unstable surface) compared with on to the floor (stable surface). HYPOTHESES: (1) The SLD on an unstable surface would lower the quadriceps to hamstrings electromyographic (EMG) activation ratio (Q:H EMG activation ratio) compared with being performed on the floor. (2) Lower Q:H EMG activation ratio would be caused by a relative increase in hamstring activation, with no significant change in quadriceps activation. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty-nine Division I National Collegiate Athletic Association (NCAA) female athletes performed 3 SLDs per leg onto a Bosu ball and onto the floor. Muscle activity of the vastus lateralis and lateral hamstrings were used to estimate peak quadriceps and hamstring activation, along with the Q:H EMG activation ratio. Kinematic measures at the knee, hip, and trunk were also estimated. Differences between landings were assessed using a 2-level analysis of variance (limb and surface). RESULTS: The maximum Q:H EMG activation ratio was significantly reduced when athletes performed an SLD onto the Bosu ball (20%, P < 0.001) compared with the floor. Peak hamstring activity was higher when athletes landed on a Bosu ball (18% higher, P = 0.029) compared with when they landed on the floor. CONCLUSION: Compared with landing on the floor (a stable surface), landing on a Bosu ball (unstable surface) changed the athlete’s co-contraction at the knee and increased hamstring activity. However, landing on a Bosu ball also decreased the athlete’s knee flexion, which was an undesired effect. CLINICAL RELEVANCE: These findings highlight the potential utility of unstable surfaces as a training tool to reduce the risk of ACL injury in female athletes. |
format | Online Article Text |
id | pubmed-4332646 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | SAGE Publications |
record_format | MEDLINE/PubMed |
spelling | pubmed-43326462016-03-01 Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies Shultz, Rebecca Silder, Amy Malone, Maria Braun, Hillary Jane Dragoo, Jason Logan Sports Health Current Research BACKGROUND: Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when performing a single-leg drop (SLD) on to a Bosu ball (unstable surface) compared with on to the floor (stable surface). HYPOTHESES: (1) The SLD on an unstable surface would lower the quadriceps to hamstrings electromyographic (EMG) activation ratio (Q:H EMG activation ratio) compared with being performed on the floor. (2) Lower Q:H EMG activation ratio would be caused by a relative increase in hamstring activation, with no significant change in quadriceps activation. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty-nine Division I National Collegiate Athletic Association (NCAA) female athletes performed 3 SLDs per leg onto a Bosu ball and onto the floor. Muscle activity of the vastus lateralis and lateral hamstrings were used to estimate peak quadriceps and hamstring activation, along with the Q:H EMG activation ratio. Kinematic measures at the knee, hip, and trunk were also estimated. Differences between landings were assessed using a 2-level analysis of variance (limb and surface). RESULTS: The maximum Q:H EMG activation ratio was significantly reduced when athletes performed an SLD onto the Bosu ball (20%, P < 0.001) compared with the floor. Peak hamstring activity was higher when athletes landed on a Bosu ball (18% higher, P = 0.029) compared with when they landed on the floor. CONCLUSION: Compared with landing on the floor (a stable surface), landing on a Bosu ball (unstable surface) changed the athlete’s co-contraction at the knee and increased hamstring activity. However, landing on a Bosu ball also decreased the athlete’s knee flexion, which was an undesired effect. CLINICAL RELEVANCE: These findings highlight the potential utility of unstable surfaces as a training tool to reduce the risk of ACL injury in female athletes. SAGE Publications 2015-03 /pmc/articles/PMC4332646/ /pubmed/25984263 http://dx.doi.org/10.1177/1941738114565088 Text en © 2015 The Author(s) |
spellingShingle | Current Research Shultz, Rebecca Silder, Amy Malone, Maria Braun, Hillary Jane Dragoo, Jason Logan Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies |
title | Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies |
title_full | Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies |
title_fullStr | Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies |
title_full_unstemmed | Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies |
title_short | Unstable Surface Improves Quadriceps:Hamstring Co-contraction for Anterior Cruciate Ligament Injury Prevention Strategies |
title_sort | unstable surface improves quadriceps:hamstring co-contraction for anterior cruciate ligament injury prevention strategies |
topic | Current Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4332646/ https://www.ncbi.nlm.nih.gov/pubmed/25984263 http://dx.doi.org/10.1177/1941738114565088 |
work_keys_str_mv | AT shultzrebecca unstablesurfaceimprovesquadricepshamstringcocontractionforanteriorcruciateligamentinjurypreventionstrategies AT silderamy unstablesurfaceimprovesquadricepshamstringcocontractionforanteriorcruciateligamentinjurypreventionstrategies AT malonemaria unstablesurfaceimprovesquadricepshamstringcocontractionforanteriorcruciateligamentinjurypreventionstrategies AT braunhillaryjane unstablesurfaceimprovesquadricepshamstringcocontractionforanteriorcruciateligamentinjurypreventionstrategies AT dragoojasonlogan unstablesurfaceimprovesquadricepshamstringcocontractionforanteriorcruciateligamentinjurypreventionstrategies |