title: Contralateral conditioning to the soleus H-reflex as a function of age and physical activity.
abstract: Coordination between ipsilateral and contralateral muscles of the lower limbs has a critical role in movement control. However, the roles that aging and physical activity have in maintaining bilateral coordination are understudied. The aim of this study was to examine the roles of physical activity and age on pathways between the soleus and tibialis anterior muscles. Fourteen young and 14 older subjects (7 active, 7 sedentary) participated. A Hoffmann (H)-reflex was elicited in the ipsilateral soleus following a conditioning stimulus to the contralateral common peroneal nerve at differing intervals (25-300 ms). Significant H-reflex facilitation from the control value was observed for the sedentary group at the 50-ms (28.7 %), 75-ms (24.5 %), and 150-ms (34.0 %) intervals when compared with the physically active group. There were also significant differences between the young and older groups. Results demonstrated differences in soleus H-reflex excitability as a result of contralateral conditioning and highlighted the influence of age and physical activity in maintaining these neural pathways.
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, 1025 E. 7th Street, SPH 114, Bloomington, IN, 47405, USA.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Ryder
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, 1025 E. 7th Street, SPH 114, Bloomington, IN, 47405, USA. kkitano@indiana.edu.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kitano
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, 1025 E. 7th Street, SPH 114, Bloomington, IN, 47405, USA.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Phipps
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, 1025 E. 7th Street, SPH 114, Bloomington, IN, 47405, USA.
authors.forename: Micah R
authors.initials: MR
authors.lastname: Enyart
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, 1025 E. 7th Street, SPH 114, Bloomington, IN, 47405, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Koceja
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D004558:Electric Stimulation; D004576:Electromyography; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000294:innervation / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D057185:Sedentary Behavior; D055815:Young Adult
keywords: Aging; Contralateral; H-reflex; Interlimb coordination; Physical activity