Energy metabolism and heart rate during treadmill exercise in the Marabou stork

Abstract

Oxygen consumption (VO2), heart rate, body temperature, and stride frequency were measured in Marabou storks walking on a treadmill at a range of speeds and gradients. VO2 was linearly related to speed at gradients up to 11 degrees and speeds up to 1.4 m . s-1, and the slope of the VO2/speed regression increased with the treadmill angle up to 9 degrees. At 11 degrees there was a fall in the slope. Analysis indicates the cost of horizontal movement of about 1.1 ml O2 . m-1 (mean wt 4.5 kg). The cost of vertical movement is 7.13 ml O2 . m-1 and the efficiency about 30%. Maximum recorded VO2 was about five times resting, and there was no indication of an oxygen debt at any value for VO2. Heart rate was directly proportional to vO2 over the range studied, and at high heart rates successive cardiac cycles overlapped. Body temperature did not change significantly during exercise. Stride frequency was linearly related to walking speed but with a nonzero intercept so that stride length changed with speed, but there was no observed change in gait with speed. These data are discussed in comparison with published scaling equations and with data from mammals.

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).…”

“…Previous studies have found the slope of the line of best fit between V O2 and U to increase with gradient (Armstrong et al, 1983;Bamford and Maloiy, 1980;Chassin et al, 1976;Clapperton, 1964;Cohen et al, 1978;Eaton et al, 1995;Farley and Emshwiller, 1996;Full and Tullis, 1990;Margaria et al, 1963;McDonough et al, 2002;Raab et al, 1976;Robbins et al, 1979;Taylor et al, 1972;Warncke et al, 1988;White and Yousef, 1978;Wunder and Morrison, 1974;Yousef et al, 1972) and the established way of calculating the efficiency of moving along gradients for comparison between different species is dependent upon there being a difference (Taylor et al, 1972).…”

“…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. (Lipp et al, 2005) -generally, for most species, as gradient increases so does V O2 at all locomotory speeds (Bedford et al, 1979;Brooks and White, 1978;Chassin et al, 1976;Clapperton, 1964;Cohen et al, 1978;…”

The metabolic cost of incline locomotion in the Svalbard rock ptarmigan (Lagopus muta hyperborea): the effects of incline grade and seasonal fluctuations in body mass

“…Much of the research in this field has focused on level treadmill locomotion, with relatively few studies examining the potential effects of inclines (Bamford and Maloiy, 1980;Ellerby et al, 2003;Rubenson et al, 2006;Snyder and Carello, 2008;Warncke et al, 1988). Examining the cost of incline locomotion is important and relevant as organisms seldom experience steady-state conditions, being faced with variable terrain over which energy demands for locomotion are continuously changing.…”

Neither season nor sex affects the cost of terrestrial locomotion in a circumpolar diving duck: the common eider (Somateria mollissima)

“…During terrestrial locomotion, a bird's rate of energy metabolism, the cost of locomotion, increases as a function of speed (U) until a morphological (mechanical) or physiological (energetic) constraint is met (Brackenbury and Avery 1980;Roberts et al 1998;Nudds et al 2010). This increase is often linear (Pinshow et al 1977;Bamford and Maloiy 1980;Taylor et al 1982;Brackenbury and Elsayed 1985;Roberts et al 1998;White et al 2008); however, nonlinearity within and between gaits is also common (Rubenson et al 2004(Rubenson et al , 2007Watson et al 2011;Nudds et al 2011). Elevated energy metabolism at faster U correlates with shorter periods of foot-ground contact, which require higher rates of force production by muscle fibres (Kram and Taylor 1990;Roberts et al 1998).…”