Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
enabled [disable] Abstract
Number of results

Results found: 4

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
EN
Oxygen uptake measurements are without question useful and a staple measurement for the estimation of exercise energy costs. However, steady state models cannot be used to successfully model intermittent resistance exercise energy costs. Our laboratory has taken steps to avoid such comparisons between these discrepant exercises. We have separated out exercise and recovery periods during resistance training and utilize capacity (kJ) estimates as opposed to rate measures (kJ min-1). Moreover, we avoid anaerobic threshold concepts as applied to resistance exercise. When viewed accordingly, resistance exercise energy costs are opposite those of the steady state model: exercise oxygen uptake is highest for steady state exercise and lowest for resistance exercise, recovery oxygen uptake can be the highest energy cost for resistance exercise whereas for steady state exercise it may or may not be meaningful, and anaerobic energy costs represent a significant component of resistance exercise that plays little to no role with steady state exercise.
EN
We present an aerobic and anaerobic, exercise and recovery energy cost model of intermittent energy costs utilizing task (work, Joules) as opposed to rate (per minute) measurements. Low to moderate intensity steady state exercise energy costs are typically portrayed as the volumetric rate at which oxygen is consumed (VO2 L min–1), where a proportionate upward climbing linear relationship is profiled with an increasing power output; add to this the concept of the anaerobic threshold and energy costs increase with more intense aerobic exercise in disproportion to VO2 L min–1 measurements. As a per task function, intermittent work and recovery bouts contain a combined estimate of total costs, that is as kJ or kcal (not kJ.min-1 or kcal.min-1). Adopting this approach to describe single and multiple sets of resistance training, the model that emerges for intermittent resistance exercise portrays linearity between equivalent work and total energy costs that differs proportionately among conditions – “continuous” muscular endurance vs. Intermittent higher load strength work, moderately paced vs. slower and faster conditions, smaller vs. larger working muscle masses and failure (fatigue) vs. non-failure states. Moreover, per kcal (or kJ) of total energy costs, work (J) is more inefficient with a greater load and lower repetition number as opposed to lower resistance with an increased number of repetitions. The concept of energy costs Rusing disproportionately with increased or prolonged work does not appear to apply to resistance exercise.
3
Content available remote

Estimating the Energy Costs of Intermittent Exercise

63%
EN
To date, steady state models represent the only acceptable methodology for the estimation of exercise energy costs. Conversely, comparisons made between continuous and intermittent exercise generally reveal major physiological discrepancies, leading to speculation as to why steady state energy expenditure models should be applied to intermittent exercise. Under intermittent conditions, skeletal muscle invokes varying aerobic and anaerobic metabolic responses, each with the potential to make significant contributions to overall energy costs. We hypothesize that if the aerobic-only energetic profile of steady state exercise can be used to estimate the energetics of non-steady state and intermittent exercise, then the converse also must be true. In fact, reasonable estimates of energy costs to work volumes or work rates can be demonstrated under steady state, non-steady state and intermittent conditions; the problem with the latter two is metabolic variability. Using resistance training as a model, estimates of both aerobic and anaerobic energy cost components, as opposed to one or the other, have reduced the overall energetic variability that appears inherent to brief, intense, intermittent exercise models.
EN
We utilized a non-steady state method (kJ per set, not kJ min–1) to estimate the total energy costs (aerobic and anaerobic, exercise and recovery) of five different resistance exercises: incline bench press, squat, deadlift, shoulder shrug and calf raise. Using a Smith machine, work was precisely measured as the product of the vertical distance the lifting bar traveled and the amount of weight lifted. The average of two lifts performed on separate days was completed by 16 women (165 cm; 61.1 kg; 21.8 years) and 22 men (180.5 cm; 83 kg; 23.7 years). Overall 40 data points (the averages of 80 lifts) were plotted and correlations completed within each exercise for work and total energy costs: deadlift r = 0.997, squat r = 0.977, incline press r = 0.947, shoulder shrug r = 0.921 and calf raise r = 0.941 (p < 0.05). The amount of oxygen consumed during exercise for each lift represented the lowest energy cost contribution (18%), followed by anaerobic (31%) and excess post-exercise oxygen consumption (EPOC, 51%) (p < 0.05). The identification of work (J) along with an estimate of the total energy costs (kJ) revealed remarkably consistent relationships within any given resistance exercise, leading to a predictable increase in the cost of lifting for each exercise. However, due to the muscle/joint and movement characteristics of each exercise, the work to cost relationship differed for all lifts.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.