TY  - JOUR
A1  - Beijersbergen, Chantal M. I.
A1  - Granacher, Urs
A1  - Gäbler, Martijn
A1  - Devita, Paul
A1  - Hortobagyi, Tibor
T1  - Power Training-induced Increases in Muscle Activation during Gait in Old Adults
JF  - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine
N2  - Introduction/Purpose: Aging modifies neuromuscular activation of agonist and antagonist muscles during walking. Power training can evoke adaptations in neuromuscular activation that underlie gains in muscle strength and power but it is unknown if these adaptations transfer to dynamic tasks such as walking. We examined the effects of lower-extremity power training on neuromuscular activation during level gait in old adults. Methods: Twelve community-dwelling old adults (age >= 65 yr) completed a 10-wk lower-extremity power training program and 13 old adults completed a 10-wk control period. Before and after the interventions, we measured maximal isometric muscle strength and electromyographic (EMG) activation of the right knee flexor, knee extensor, and plantarflexor muscles on a dynamometer and we measured EMG amplitudes, activation onsets and offsets, and activation duration of the knee flexors, knee extensors, and plantarflexors during gait at habitual, fast, and standardized (1.25 +/- 0.6 m.s(-1)) speeds. Results: Power training-induced increases in EMG amplitude (similar to 41%; 0.47 <= d <= 1.47; P <= 0.05) explained 33% (P = 0.049) of increases in isometric muscle strength (similar to 43%; 0.34 <= d <= 0.80; P <= 0.05). Power training-induced gains in plantarflexor activation during push-off (+11%; d = 0.38; P = 0.045) explained 57% (P = 0.004) of the gains in fast gait velocity (+4%; d = 0.31; P = 0.059). Furthermore, power training increased knee extensor activation (similar to 18%; 0.26 <= d <= 0.29; P <= 0.05) and knee extensor coactivation during the main knee flexor burst (similar to 24%, 0.26 <= d <= 0.44; P <= 0.05) at habitual and fast speed but these adaptations did not correlate with changes in gait velocity. Conclusions: Power training increased neuromuscular activation during isometric contractions and level gait in old adults. The power training-induced neuromuscular adaptations were associated with increases in isometric muscle strength and partly with increases in fast gait velocity.
KW  - WALKING
KW  - MUSCLE
KW  - EXERCISE
KW  - EMG
Y1  - 2017
U6  - https://doi.org/10.1249/MSS.0000000000001345
SN  - 0195-9131
SN  - 1530-0315
VL  - 49
SP  - 2198
EP  - 2205
PB  - Lippincott Williams & Wilkins
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - Beijersbergen, Chantal M. I.
A1  - Granacher, Urs
A1  - Gaebler, Martijn
A1  - DeVita, Paul
A1  - Hortobagyi, Tibor
T1  - Hip mechanics underlie lower extremity power training-induced increase  in old adults’ fast gait velocity
BT  - the Potsdam Gait Study (POGS)
JF  - Gait & posture
N2  - Methods: As part of the Potsdam Gait Study (POGS), healthy old adults completed a no-intervention control period (69.1 +/- 4A yrs, n =14) or a power training program followed by detraining (72.9 +/- 5.4 yrs, n = 15).We measured isokinetic knee extensor and plantarflexor power and measured hip, knee and ankle kinetics at habitual, fast and standardized walking speeds. Results: Power training significantly increased isokinetic knee extensor power (25%), plantarflexor power (43%), and fast gait velocity (5.9%). Gait mechanics underlying the improved fast gait velocity included increases in hip angular impulse (29%) and H1 work (37%) and no changes in positive knee (K2) and A2 work. Detraining further improved fast gait velocity (4.7%) with reductions in H1(-35%), and increases in K2 (36%) and A2 (7%). Conclusion: Power training increased fast gait velocity in healthy old adults by increasing the reliance on hip muscle function and thus further strengthened the age-related distal-to-proximal shift in muscle function. (C) 2016 Elsevier B.V. All rights reserved.
KW  - Walking
KW  - Biomechanics
KW  - Detraining
KW  - Muscle
KW  - Exercise
Y1  - 2017
U6  - https://doi.org/10.1016/j.gaitpost.2016.12.024
SN  - 0966-6362
SN  - 1879-2219
VL  - 52
SP  - 338
EP  - 344
PB  - Elsevier
CY  - Clare
ER  -