Abstract:
Running has become an immensely popular form of exercise for recreational,
professional, social, health, and overall fitness purposes. There is no shortage of existing
research on lower extremity running mechanics and sex differences in running-related injury
rates, but research regarding pelvic obliquity (PVO), upper extremity running mechanics, and
isometric trunk strength is limited. The purpose of this study was to determine the connection
between PVO, arm swing crossover (ASC), and trunk and pelvic strength as a function of
running speed in recreational distance runners and to determine whether sex differences exist in
these relationships. Data from 16 apparently healthy recreational runners (age 24.25 ± 4.25
years; 6 females) were analyzed in this study. Motion capture data was collected during four, 2-
minute treadmill running trials at varying speeds between 2.68 and 4.02 m∙s-1, followed by a
series of maximal voluntary isometric contraction (MVIC) tests for lateral trunk flexion, trunk
rotation, hip abduction, and unilateral hip flexion and extension strength. While significant
correlations were found between PVO and right ASC at some speeds (3.13 m∙s-1 – p = .027, 3.57
m∙s-1 – p = .048), PVO shared no correlations with left ASC (p > .05). Significant negative
correlations were found between left ASC and various strength measures (p < .05), while right
ASC was only correlated with right hip abduction strength (p < .04). Significant main effects of
speed were observed on PVO (p = .004) and right ASC (p = .003). Findings suggest that limb
dominance, strength differences between left and right limbs, and neuromuscular movement patterns may have contributed to asymmetric biomechanical relationships between left and right sides. Speed effects on running kinematics may have been influenced by neuromuscular control abilities, novelty of certain speeds, and differences in energy demands.
