title: Lower limb moments differ when towing a weighted sled with different attachment points.
abstract: Sprinting while towing a sled improves sprinting parameters, however, only kinematic and temporal-spatial variables have been reported. The purpose of this study was to determine how lower extremity joint moment impulses alter when towing a sled compared to normal walking. Twelve participants walked normally, walked while towing a sled with a 50% body weight load attached at the waist, and with a 50% body weight load attached at the shoulders. Joint moment impulses were calculated for the hip, knee, and ankle. A mixed-model ANOVA with a between-subject factor of limb and repeated measures of condition was used to compare differences between limbs and towing conditions for each joint. Towing a sled increased joint moment impulses at the hip, knee, and non-dominant ankle. When compared with normal walking waist attachment increased hip extension moment impulse by 214.5% (-3.31 vs. -10.41Nms/kg), and shoulder attachment increased knee extension moment impulse by 166.9% (4.62 vs. 12.33Nms/kg). The dominant limb produced greater knee extension moment impulse (p < 0.001), while the non-dominant limb produced greater hip extension (p < 0.001) and ankle plantarflexion moment impulse (p < 0.001) across all conditions. Results suggest that walking while towing may increase hip and knee extension strength.
authors.affiliation: Department of Physical Therapy, University of New England, Portland, ME 04103, USA. mlawrence3@une.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Lawrence
authors.forename: Erin
authors.initials: E
authors.lastname: Hartigan
authors.forename: Chunhao
authors.initials: C
authors.lastname: Tu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D007839:Functional Laterality; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D011187:Posture; D019876:Sports Equipment; D013997:Time Factors; D016138:Walking / Q000502:physiology*; D055815:Young Adult