Lower Extremity Kinematic and Kinetic Characteristics as Effects on Running Economy of Recreational Runners

PurposeThis study aimed to determine associations between running economy (RE) and running sagittal plane kinematic and kinetic parameters.MethodA total of 30 male recreational runners (age: 21.21 +/- 1.22 yr, VO2max: 54.61 +/- 5.42 mL<middle dot>kg-1<middle dot>min-1) participated in two separate test sessions. In the first session, the participant's body composition and RE at 10 and 12 km<middle dot>h-1 were measured. In the second session, measurements were taken for the sagittal plane of hip, knee, and ankle angles and range of motion (ROM), as well as ground reaction force.ResultsModerate correlations were found between lower energy costs at 12 km<middle dot>h-1 and smaller hip flexion at toe-off (r = 0.373) as well as smaller peak hip flexion during stance (r = 0.397). During the swing phase, lower energy costs at 10 km<middle dot>h-1 were moderately correlated with smaller peak knee flexion and smaller knee flexion and extension ROM (r = 0.366-0.443). Lower energy costs at 12 km<middle dot>h-1 were moderately correlated with smaller peak hip and knee flexion as well as knee extension ROM (r = 0.369-0.427). In terms of kinetics, there was a moderate correlation between higher energy costs at 10 km<middle dot>h-1 and larger peak active force, as well as larger peak braking and propulsion force (r = -0.470-0.488). Lower energy costs at 12 km<middle dot>h-1 were moderately to largely correlated with smaller peak impact and braking force (r = 0.486 and -0.500, respectively). Regarding the statistical parametric mapping analysis, most outcomes showed associations with RE at 10 km<middle dot>h-1, including knee flexion (42.5%-65.5% of the gait cycle), ankle plantarflexion (32.5%-36% of the gait cycle), active force (30.5%-35% of the stance phase), and propulsion force (68%-72.5% of the stance phase). Lower energy costs at 12 km<middle dot>h-1 were correlated with smaller hip flexion (5.5%-12% and 66.5%-74%) and smaller knee flexion (57%-57.5%) during the running gait cycle.ConclusionsThis study indicates that biomechanical factors are associated with RE in recreational runners. To design effective training methods to improve RE, coaches and runners should focus on the sagittal plane kinematics of the hip, knee, and ankle, as well as lower vertical and horizontal kinetic parameters.