The energetics of the trot–gallop transition

Abstract

One of the most obvious locomotory behaviors is gait transition (changing from walk to trot/run and changing from trot to gallop). There have been numerous attempts to explain gait transitions. These include considerations of muscle function (Taylor, 1978(Taylor, , 1985 and bone strain (Biewener and Taylor, 1986;Rubin and Lanyon, 1982), theoretical explanations based on mathematical models (Alexander, 1989;Alexander and Jayes, 1983), psychological factors (Diedrich and Warren, 1995) and engineering models (Schoner et al., 1990;Vilensky et al., 1991).The walk-trot and trot-gallop gait transitions were originally explained on the basis of metabolic economy (Hoyt and Taylor, 1981). In ponies (Equus caballus), metabolism increased curvilinearly for walking and trotting, and the gait transitions occurred at the speeds where the metabolism curves intersected. This is referred to as the 'energetically optimal transition speed' (EOTS; Hreljac, 1993) because, when the animals extended their gaits beyond the normal transition speeds, the metabolic rate was higher in the extended gait than in the normal gait. Hoyt and Taylor concluded that ponies changed gaits to minimize energetic costs. However, one limitation of this study was that gait transition speeds were not rigorously determined.Subsequently, this explanation was challenged by the 'force trigger' hypothesis. Farley and Taylor (1991) showed that the transition from trotting to galloping in ponies is correlated with musculoskeletal forces by demonstrating that the transition occurs at a slower speed when a pony carries a load. Measurements of oxygen consumption (again observed to be a curvilinear function of speed) indicated that the ponies were making the transition to a gallop at speeds where it is energetically more expensive to gallop than to trot -at speeds slower than the EOTS. In some studies, the walk-run transition in humans occurs at the EOTS (Mercier et al., 1994;Diedrich and Warren, 1995) and in others it does not (Hreljac, 1993; Minetti et al., 1994a,b). Hreljac (1993) ruled out muscle stress as the trigger for the walk-run transition in humans and suggested that the trigger is kinematic (Hreljac, 1995).In a study of horses and preferred speed , the energetics of trotting were measured on the level and up a 10% incline. In the preliminary portion of this study, we determined the speeds at which the horses would trot. We noted that, when trotting up an incline, the horses made the transition to a gallop at a slower speed than they would when on the level. Because forces are not expected to be higher when Two studies have focused on potential triggers for the trot-gallop transition in the horse. One study concluded that the transition was triggered by metabolic economy. The second study found that it was not metabolic factors but, rather, peak musculoskeletal forces that determine gait transition speeds. In theory, peak musculoskeletal forces should be the same when trotting up an incline as when trotting at the same speed on the level. Assuming this is ...

The metabolic cost of walking on gradients with a waddling gait

“…The increase in metabolic cost when moving up an incline agrees with previous studies (Armstrong et al, 1983;Bamford and Maloiy, 1980;Bedford et al, 1979;Brooks and White, 1978;Chassin et al, 1976;Clapperton, 1964;Cohen et al, 1978;Dill, 1965;Eaton et al, 1995;Ellerby et al, 2003;Farley and Emshwiller, 1996;Margaria et al, 1963;McDonough et al, 2002;Minetti et al, 2002;Raab et al, 1976;Robbins et al, 1979;Rubenson et al, 2006;Snyder and Carello, 2008;Taylor et al, 1972;Warncke et al, 1988;White and Yousef, 1978;Wickler et al, 2000;Wickler et al, 2003;Wunder and Morrison, 1974;Yousef et al, 1972). The finding that descending a decline is not metabolically cheaper than locomoting on the level, however, is contrary to previous findings (Armstrong et al, 1983;Byrnes et al, 1985;Cohen et al, 1978;Margaria et al, 1963;Minetti et al, 2002;Raab et al, 1976;Robbins et al, 1979;Taylor et al, 1972;White and Yousef, 1978;Yousef et al, 1972).…”

“…Additional muscle activity means that whole-animal metabolic costs (rate of O 2 consumption, V O2 ) should also increase (Ellerby et al, 2003), assuming that additional costs are met aerobically. Accordingly, increased metabolic costs were found in birds (Bamford and Maloiy, 1980;Ellerby et al, 2003;Rubenson et al, 2006;Snyder and Carello, 2008;Warncke et al, 1988), humans (Dill, 1965;Margaria et al, 1963;Minetti et al, 2002;Yousef et al, 1972), a range of quadrupeds (Armstrong et al, 1983;Bedford et al, 1979;Brooks and White, 1978;Chassin et al, 1976;Clapperton, 1964;Cohen et al, 1978;Eaton et al, 1995;Farley and Emshwiller, 1996;McDonough et al, 2002;Raab et al, 1976;Robbins et al, 1979;Snyder and Carello, 2008;Taylor et al, 1972;White and Yousef, 1978;Wickler et al, 2000;Wickler et al, 2003;Wunder and Morrison, 1974;Yousef et al, 1972) and invertebrates (Full and Tullis, 1990;Tullis and Andrus, 2011) when ascending gradients. Although there are notable exceptions -the marabou stork Leptoptilos crumeniferus (Bamford and Maloiy, 1980), cockroach Gromphadorhina portento (Herreid et al, 1981) and ant Camponotus sp.…”

The energy cost of voluntary running in weasels,Mustela nivalis

“…In much larger animals (horses), gait shifts may reduce costs of transport and peak musculoskeletal forces (e.g. Hoyt and Taylor, 1981;Wickler et al, 2003). In weasels, we observed walking (at low speed) and bounding (at high speed) both in the wild and in our wheel respirometers.…”

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). From this, it was concluded that conflicting signals, other than metabolic cost, are probably responsible for the trot-gallop transition.…”