title: Which muscles compromise human locomotor performance with age?
abstract: Ageing leads to a progressive decline in human locomotor performance. However, it is not known whether this decline results from reduced joint moment and power generation of all lower limb muscle groups or just some of them. To further our understanding of age-related locomotor decline, we compare the amounts of joint moments and powers generated by lower limb muscles during walking (self-selected), running (4 m s(-1)) and sprinting (maximal speed) among young, middle-aged and old adults. We find that age-related deficit in ankle plantarflexor moment and power generation becomes more severe as locomotion change from walking to running to sprinting. As a result, old adults generate more power at the knee and hip extensors than their younger counterparts when walking and running at the same speed. During maximal sprinting, young adults with faster top speeds demonstrate greater moments and powers from the ankle and hip joints, but interestingly, not from the knee joint when compared with the middle-aged and old adults. These findings indicate that propulsive deficit of ankle contributes most to the age-related locomotor decline. In addition, reduced muscular output from the hip rather than from knee limits the sprinting performance in older age.
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Viveca 223, Rautpohjankatu 8 A, 40014 Jyväskylän Yliopisto, Finland Agora Center, University of Jyväskylä, Viveca 223, Rautpohjankatu 8 A, 40014 Jyväskylän Yliopisto, Finland Department of Mechanical Engineering, Lappeenranta University of Technology, 53850 Lappeenranta, Finland juhapekka.kulmala@gmail.com.
authors.forename: Juha-Pekka
authors.initials: JP
authors.lastname: Kulmala
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Viveca 223, Rautpohjankatu 8 A, 40014 Jyväskylän Yliopisto, Finland.
authors.forename: Marko T
authors.initials: MT
authors.lastname: Korhonen
authors.affiliation: Research Institute for Olympic Sports, 40700 Jyväskylä, Finland.
authors.forename: Sami
authors.initials: S
authors.lastname: Kuitunen
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Viveca 223, Rautpohjankatu 8 A, 40014 Jyväskylän Yliopisto, Finland.
authors.forename: Harri
authors.initials: H
authors.lastname: Suominen
authors.affiliation: Department of Health Sciences, University of Jyväskylä, Viveca 223, Rautpohjankatu 8 A, 40014 Jyväskylän Yliopisto, Finland.
authors.forename: Ari
authors.initials: A
authors.lastname: Heinonen
authors.affiliation: Department of Mechanical Engineering, Lappeenranta University of Technology, 53850 Lappeenranta, Finland.
authors.forename: Aki
authors.initials: A
authors.lastname: Mikkola
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Viveca 223, Rautpohjankatu 8 A, 40014 Jyväskylän Yliopisto, Finland.
authors.forename: Janne
authors.initials: J
authors.lastname: Avela
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000842:Ankle / Q000502:physiology; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012420:Running / Q000502:physiology*; D016138:Walking / Q000502:physiology*
keywords: ageing; biomechanics; gait; joint kinetics; running; walking