The metabolic cost of human running: is swinging the arms worth it? (original) (raw)
Related papers
Metabolic cost of generating horizontal forces during human running
Journal of Applied Physiology, 1999
Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to −6, −3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (V˙o2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of −6% BWt,V˙o2increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted ∼70% less propulsive impulse and exhibited a 33% reduction inV˙o2. Our data suggest that generating horizont...
The effect of restricted arm swing on energy expenditure in healthy men
International Journal of Rehabilitation Research, 2009
The purpose of this investigation was to compare the thermoregulatory responses during exercise in a hot climate among three age categories. Eight prepubertal (PP), eight young adult (Y) and eight elderly (O) male subjects cycled at an intensity of 50 ± 1% of their maximum oxygen uptake (V O 2 peak ) for 85 min (three 20 min bouts with three 7 min rest periods) in hot and dry conditions (41 ± 0.67 • C, 21 ± 1% relative humidity). During the exercise-in-heat protocol, rectal temperature (T re ) skin temperatures (T sk ), heart rate (HR),V O 2 ,V CO 2 ,V E , RER, sweat rate, and the number of heat activated sweat glands (HASG) were determined. Despite highest and lowest end-exposure T re in the Y and O groups, respectively, the rise in rectal temperature (accounting for differences in baseline T re ) was similar in all age groups. Changes in body heat storage (∆S), both absolute and relative to body mass, were highest in the Y and O groups and lowest in the PP group. While end-session as well as changes in mean skin temperature were similar in all three age groups, HR (absolute and percentage of maximum) was significantly lower for the O compared with the PP and Y groups. Total body as well as per body surface sweating rate was significantly lower for the PP group, while body mass-related net metabolic heat production ((M − W ) kg −1 ) and heat gained from the environment were highest in the PP and lowest in the O group. Since mass-related evaporative cooling (E sk kg −1 ) and sweating efficiency (E sk /M sw kg −1 ) were highest in the PP and lowest in the O group, the mass-dependent heat stored in the body (∆S kg −1 ) was lowest in the PP (1.87 ± 0.03 W kg −1 ) and highest in Y and O groups (2.19 ± 0.08 and 1.97 ± 0.11 W kg −1 , respectively). Furthermore, it was calculated that while the O group required only 4.1 ± 0.5 W of heat energy to raise their body core temperature by 1 • C, and the Y group needed 6.9 ± 0.9 W (1 • C) −1 , the PP group required as much as 12.3 ± 0.7 W to heat up their body core temperature by 1 • C. These results suggest that in conditions similar to those imposed during this study, age and age-related characteristics affect the overall rate of heat gain as well as the mechanisms through which this heat is being dissipated. While prepubertal boys seem to be the most efficient thermoregulators, the elderly subjects appear to be the least efficient thermoregulators.
Energy cost and physiological responses during upper body exercise with different postures
Revista Andaluza de Medicina del Deporte, 2018
Objective: The physiological and energy demand responses to upper body aerobic exercises performed with different postures are not well known. The aim of the present study was to compare energy cost and physiological responses to upper body aerobic exercises performed with different postures. Method: Eight physically active males (>1 year active), untrained in upper body aerobic exercises, with 28.2 ± 5.7 years, ht 173.7 ± 7.4 cm, body mass 74.1 ± 11.4 kg, VO 2Peak 30.2 ± 2.09 ml/kg/min and Body Mass Index 24.4 ± 2.5 kg/m 2 performed a preliminary maximal test and two upper body aerobic exercises 30-min sessions in different days. Results: Metabolic and hemodynamic responses to upper body aerobic exercises performed in sit-position and vertical-position were compared. The vertical-position trial showed greater total energy cost (14.3%; p = 0.01), higher lipid catabolism (p = 0.001) and a higher double product (p = 0.04), when compared to the sit-position trial. Conclusion: The upper body aerobic exercises performed in vertical-position induces a higher energetic demand and cardiovascular load than in sit-position.
Muscle work is biased toward energy generation over dissipation in non-level running
Journal of biomechanics, 2008
This study tested the hypothesis that skeletal muscles generate more mechanical energy in gait tasks that raise the center of mass compared to the mechanical energy they dissipate in gait tasks that lower the center of mass despite equivalent changes in total mechanical energy. Thirteen adults ran on a 10° decline and incline surface at a constant average velocity. Three-dimensional (3D) joint powers were calculated from ground force and 3D kinematic data using inverse dynamics. Joint work was calculated from the power curves and assumed to be due to skeletal muscle-tendon actuators. External work was calculated from the kinematics of the pelvis through the gait cycle. Incline vs. decline running was characterized with smaller ground forces that operated over longer lever arms causing larger joint torques and work from these torques. Total lower extremity joint work was 28% greater in incline vs. decline running (1.32 vs. −1.03 J/kg m, p<0.001). Total lower extremity joint work comprised 86% and 71% of the total external work in incline (1.53 J/kg m) and decline running (−1.45 J/kg m), which themselves were not significantly different (p<0.180). We conjectured that the larger ground forces in decline vs. incline running caused larger accelerations of all body tissues and initiated a greater energy-dissipating response in these tissues compared to their response in incline running. The runners actively lowered themselves less during decline stance and descended farther as projectiles than they lifted themselves during incline stance and ascended as projectiles. These data indicated that despite larger ground forces in decline running, the reduced displacement during downhill stance phases limited the work done by muscle contraction in decline compared to incline running.
Physiological Comparison of Concentric and Eccentric Arm Cycling in Males and Females
PLoS ONE, 2014
Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC) or concentric (CON) arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial. The heart rate, ventilation, cardiac output, respiratory exchange ratio, and blood lactate concentrations were all clearly greater in CON condition at all of the relative workloads (all p,0.003). Effect size calculations demonstrated that the magnitude of the differences in VO 2 and work economy between the ECC and CON exercise ranged from very large to extremely large; however, in no case did mechanical efficiency (g MECH) differ between the conditions (all p.0.05). In contrast, delta efficiency (g D), as previously defined by Coyle and colleagues in 1992, demonstrated a sex difference (men.women; p,0.05). Sex differences were also apparent in arteriovenous oxygen difference and heart rate during CON. Here, we reinforce the highforce, low cost attributes of eccentric exercise which can be generalised to the muscles of the upper body. Upper body eccentric exercise is likely to form a useful adjunct in debilitative, rehabilitative, and adaptive clinical exercise programs; however, reports of a shift towards an oxidative phenotype should be taken into consideration by power athletes. We suggest delta efficiency as a sensitive measure of efficiency that allowed the identification of sex differences.
Influence of Arm Swing on Cost of Transport during Walking
2018
ABSTRACTNormal arm swing plays a role in decreasing the cost of transport during walking. However, whether excessive arm swing can reduce the cost of transport even further is unknown. Therefore, we tested the effects of normal and exaggerated arm swing on the cost of transport in the current study. Healthy participants (n=12) walked on a treadmill (1.25 m/s) in seven trials with different arm swing amplitudes (in-phase, passive restricted, active restricted, normal, three gradations of extra arm swing), while metabolic energy cost and the vertical angular momentum (VAM) and ground reaction moment (GRM) were measured.In general, VAM and GRM decreased as arm swing amplitude was increased, except for in the largest arm swing amplitude condition. The decreases in VAM and GRM were accompanied by a decrease in cost of transport from in-phase walking (negative amplitude) up to a slightly increased arm swing (non-significant difference compared to normal arm swing). The most excessive arm ...
Effects of aging and arm swing on the metabolic cost of stability in human walking
Journal of Biomechanics, 2008
To gain insight into the mechanical determinants of walking energetics, we investigated the effects of aging and arm swing on the metabolic cost of stabilization. We tested two hypotheses: 1) elderly adults consume more metabolic energy during walking than young adults because they consume more metabolic energy for lateral stabilization, and 2) arm swing reduces the metabolic cost of stabilization during walking in young and elderly adults. To test these hypotheses, we provided external lateral stabilization by applying bilateral forces (10% body weight) to a waist belt via elastic cords while young and elderly subjects walked at 1.3 m/s on a motorized treadmill with arm swing and with no arm swing. We found that the external stabilizer reduced the net rate of metabolic energy consumption to a similar extent in elderly and young subjects. This reduction was greater (6-7%) when subjects walked with no arm swing than when they walked normally (3-4%). When young or elderly subjects eliminated arm swing while walking with no external stabilization, net metabolic power increased by 5-6%. We conclude that the greater metabolic cost of walking in elderly adults is not caused by a greater cost of lateral stabilization. Moreover, arm swing reduces the metabolic cost of walking in both young and elderly adults likely by contributing to stability.
2021
Human running features a spring-like interaction of body and ground, enabled by elastic tendons that store mechanical energy and facilitate muscle operating conditions to minimize the metabolic cost. By experimentally assessing the operating conditions of two important muscles for running, the soleus and vastus lateralis, we investigated physiological mechanisms of muscle work production and muscle force generation. We found that the soleus continuously shortened throughout the stance phase, operating as work generator under conditions that are considered optimal for work production: high force-length potential and high enthalpy efficiency. The vastus lateralis promoted tendon energy storage and contracted nearly isometrically close to optimal length, resulting in a high force-length-velocity potential beneficial for economical force generation. The favorable operating conditions of both muscles were a result of an effective length and velocitydecoupling of fascicles and muscle-tendon unit, mostly due to tendon compliance and, in the soleus, marginally by fascicle rotation.
Evaluating the “cost of generating force” hypothesis across frequency in human running and hopping
2022
The volume of active muscle and duration of extensor muscle force well-explain the associated metabolic energy expenditure across body mass and speed during level-ground running and hopping. However, if these parameters fundamentally drive metabolic energy expenditure, then they should pertain to multiple modes of locomotion and provide a simple framework for relating biomechanics to metabolic energy expenditure in bouncing gaits. Therefore, we evaluated the ability of the ‘cost of generating force’ hypothesis to link biomechanics and metabolic energy expenditure during human running and hopping across step frequencies. We asked participants to run and hop at 0%, ±8% and ±15% of preferred step frequency. We calculated changes in active muscle volume, force duration, and metabolic energy expenditure. Overall, as step frequency increased, active muscle volume decreased due to postural changes via effective mechanical advantage (EMA) or duty factor. Accounting for changes in EMA and mu...
The effect of forward postural lean on running economy, kinematics, and muscle activation
PloS one, 2024
Background Running economy, commonly defined as the metabolic energy demand for a given submaximal running speed, is strongly associated with distance running performance. It is commonly believed among running coaches and runners that running with increased forward postural lean either from the ankle or waist improves running economy. However, recent biomechanical research suggests using a large forward postural lean during running may impair running economy due to increased demand on the leg muscles. Purpose This study tests the effect of altering forward postural lean and lean strategy on running economy, kinematics, and muscle activity. Methods 16 healthy young adult runners (23±5 years, 8M/8F) ran on a motorized treadmill at 3.58m/s using three postural lean angles [upright, moderate lean (50% of maximal lean angle), and maximal lean] and two strategies (lean from ankle and lean from waist [trunk lean]). Metabolic energy consumption, leg kinematics, and muscle activation data were recorded for all trials. Results Regardless of lean strategy, running with an increased forward postural lean (up to 8±2 degrees) increased metabolic cost (worsened economy) by 8% (p < .001), increased hip flexion (p < .001), and increased gluteus maximus (p = .016) and biceps femoris (p = .02) muscle activation during the stance phase. This relation between running economy and postural lean angle was similar between the ankle and trunk lean strategies (p = .743). Conclusion Running with a large forward postural lean reduced running economy and increased reliance on less efficient extensor leg muscles. In contrast, running with a more upright or