The transition between walking and running in humans: metabolic and mechanical aspects at different gradients

Abstract

Five subjects walked and ran at overlapping speeds and different gradients on a motorized treadmill. At each gradient the speed was obtained at which walking and running have the same metabolic cost (Sm) and the speed of spontaneous (Ss) transition between the two gaits was measured. Ss was found to be statistically lower than Sm at all gradients, the difference being in the range of 0.5-0.9 km h-1. The motion analysis of walking reveals that at all gradients and at increasing speed: (1) the percentage of recovery, an index of mechanical energy saving related to the pendulum-like characteristic of walking, decreases; (2) the lower limb spread reaches a limit in walking; and consequently (3) both the stride frequency and the internal mechanical work, due to limb acceleration in relation to the body centre of mass, increase much more in walking than in running. Switching to a run, although implying a higher frequency, makes the internal work decrease as a result of the lower limb spread. In this paper several influences, such as the 'ratings of perceived exertion' (RPE), on the choice of beginning to run when it is more economical to walk, are discussed. A tentative hypothesis on the determinants of Ss, which is emphasized to be a speed which has to be studied in detail but is generally avoided in locomotion, is based on a comfort criterion from peripheric afferences and is reflected by the fact that at Ss a running stride costs as much as a walking stride.(ABSTRACT TRUNCATED AT 250 WORDS)

Compliant leg behaviour explains basic dynamics of walking and running

“…A similar speed gap, albeit not as large, is found in experiments on the human gait transition. Even though humans prefer to switch from walking to running at one speed of about 2.3 m s K1 when they are instructed to walk or run at different speeds on a treadmill (Thorstensson & Roberthson 1987;Hreljac 1993), they immediately switch from walking at about 1.8 m s K1 to running at about 2.3 m s K1 during spontaneous overground progression (Minetti et al 1994), which more closely resembles the natural situation.…”

Influence of M. tibialis anterior fatigue on the walk-to-run and run-to-walk transition in non-steady state locomotion

“…Some studies suggested that the walk-to-run transition (WRT) is closely linked to the minimization of metabolic cost [7,8]. Others found evidence to reject this energy optimisation hypothesis [9][10][11][12][13]. This contradiction can be partly explained by the difficulties in directly measuring the metabolic cost [6,7].…”

Gait selection in the ostrich: mechanical and metabolic characteristics of walking and running with and without an aerial phase

“…The metabolic-trigger hypothesis has been argued against (Farley & Taylor 1991;Hreljac 1993;Minetti et al 1994;Brisswalter & Mottet 1996) on the basis that self-selected gait transition can occur at non-energetically-optimal speeds, despite the obvious optimization at slower and faster speeds. More recently, horses have been found to switch repeatedly between trotting and galloping over a narrow range of speeds where galloping is metabolically optimal (Wickler et al 2003).…”