Background: The head, arms and trunk segment constitute a large proportion of the body's mass. Therefore, small alterations in trunk inclination may affect lower limb joint moments and muscle activation patterns. Although previous research has investigated the effect of changing frontal plane inclination of the trunk, it is not clear how increasing trunk flexion will impact on the activation of the lower limb muscles.
Research Question: What is the effect of independently manipulating trunk flexion angle on lower limb kinematics, moments and muscle function?
Methods: Gait analysis was carried out on 20 healthy people under four trunk flexion conditions: normal walking (NW), NW-5°, NW+5° and NW+10°. For the latter three conditions, a biofeedback approach was used to tightly control trunk flexion angle. A linear mixed model was used to investigate the effect of changing trunk flexion on joint angles, moments, and knee muscle activation.
Results: There were clear increases in hip and ankle moments as trunk flexion was increased, but no change in knee moments. The results also showed a linear increase in knee flexor muscle activity and a corresponding increase in co-contraction as trunk flexion increased. Interestingly, there was a dramatic change in the profile of hamstring activity. In the medial hamstrings, this change led to a 100% increase in activation during early stance as flexion was increased by 5° from NW.
Significance: This is the first study to demonstrate a strong dependence of knee flexor muscle activity on trunk flexion. This is important as people with knee osteoarthritis have been observed to walk with elevated muscle activation and this has been linked to increased joint loads. It is possible that these altered muscle patterns may result from increased trunk flexion during walking.
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http://dx.doi.org/10.1016/j.gaitpost.2020.10.021 | DOI Listing |
Sci Rep
January 2025
Department of Sport Biomechanics, Faculty of Sports Sciences, Bu-Ali Sina University, Hamedan, Iran.
Most sports and leisure activities involve repetitive movements in the upper limb, which are typically linked to pain and discomfort in the neck and shoulder area. Movement variability is generally expressed by changes in movement parameters from one movement to another and is a time-dependent feature of repetitive activities. The purpose of this study was to examine the effect of repeated movement-induced fatigue on biomechanical coordination and variability in athletes with and without chronic shoulder pain (CSP).
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January 2025
Department of Physical Education, Jeonbuk National University, Jeonju, Republic of Korea.
The arm slot (AS) angle reflects the pitching style of baseball pitchers. Baseball pitchers at different levels exhibit different AS angle distributions and different pitching mechanics. The present study divided 66 elite baseball pitchers from the Open Biomechanics database into 3 groups based on AS angles: ASMi, ASMo, ASMa.
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December 2024
Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA, USA.
As PI-LL mismatch is an effective index for spinal surgery and PI-LL less than 10 probably indicates better quality of life, this study aimed to assess spinopelvic parameters, lumbar instability, and lumbar muscle morphology in patients with chronic low back pain (CLBP) with different PI-LL mismatches. This cross-sectional study included 158 CLBP patients. The association between lumbar extensor muscle morphology (measured from magnetic resonance imaging) and spinopelvic parameters (measured from standing lateral radiographs) and lumbar instability (measured from lumbar flexion/extension radiographs) was compared between two groups of patients with different PI-LL mismatch.
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December 2024
Department of Orthopaedics and Traumatology, The University of Hong Kong, Pok Fu Lam, Hong Kong.
Establishing normative values and understanding how proprioception varies among body parts is crucial. However, the variability across individuals, especially adolescents, makes it difficult to establish norms. This prevents further investigation into classifying patients with abnormal proprioception.
View Article and Find Full Text PDFGait Posture
December 2024
Department of Exercise and Rehabilitation Sciences, College of Health and Human Services, University of Toledo, Toledo, OH, USA; Department of Health and Human Performance, Congdon School of Health Sciences, High Point University, High Point, NC, USA. Electronic address:
Background: People with patellofemoral pain (PFP) may have bilateral deficits in hop for distance test (SLHD) performance, whereas the worsening performance of the pain-free or less painful limbs suggests that bilateral movement differences may occur. While clinicians may not be aware of bilateral movement differences that may be employed during the clinical assessment of SLHD performance (e.g.
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