Anaerobic capacity and muscle activation during horizontal and uphill running

1997 ◽  
Vol 83 (1) ◽  
pp. 262-269 ◽  
Author(s):  
Mark A. Sloniger ◽  
Kirk J. Cureton ◽  
Barry M. Prior ◽  
Ellen M. Evans
Keyword(s):  
Lower Extremity ◽  
Muscle Activation ◽  
Anaerobic Capacity ◽  
Magnetic Resonance Images ◽  
Muscle Volume ◽  
Treadmill Running ◽  
Oxygen Deficit ◽  
Before And After ◽  
The Mean ◽  
Exercise Induced

Sloniger, Mark A., Kirk J. Cureton, Barry M. Prior, and Ellen M. Evans. Anaerobic capacity and muscle activation during horizontal and uphill running. J. Appl. Physiol. 83(1): 262–269, 1997.—Anaerobic capacity as measured by the maximal or peak oxygen deficit is greater during uphill than during horizontal running. The objective of this study was to determine whether the greater peak oxygen deficit determined during uphill compared with horizontal running is related to greater muscle volume or mass activated in the lower extremity. The peak oxygen deficit in 12 subjects was determined during supramaximal treadmill running at 0 and 10% grade. Exercise-induced contrast shifts in magnetic resonance images were obtained before and after exercise and used to determine the percentage of muscle volume activated. The mean peak oxygen deficit determined for uphill running [2.96 ± 0.63 (SD) liters or 49 ± 6 ml/kg] was significantly greater ( P < 0.05) than for horizontal running (2.45 ± 0.51 liters or 41 ± 7 ml/kg) by 21%. The mean percentage of muscle volume activated for uphill running [73.1 ± 7.4% (SD)] was significantly greater ( P < 0.05) than for horizontal running (67.0 ± 8.3%) by 9%. The differences in peak oxygen deficit (liters) between uphill and horizontal running were significantly related ( y = 8.05 × 10−4 x + 0.35; r = 0.63, SE of estimate = 0.29 liter, P < 0.05) to the differences in the active muscle volume (cm3) in the lower extremity. We conclude that the higher peak oxygen deficit during uphill compared with horizontal running is due in part to increased mass of skeletal muscle activated in the lower extremity.

scholarly journals Role of Occupational Footwear and Prolonged Walking on Lower Extremity Muscle Activation during Maximal Exertions and Postural Stability Tasks

Biomechanics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 202-213
Author(s):  
Harish Chander ◽  
Sachini N. K. Kodithuwakku Arachchige ◽  
Alana J. Turner ◽  
Reuben F. Burch V ◽  
Adam C. Knight ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Postural Stability ◽  
Muscle Activation ◽  
Medial Gastrocnemius ◽  
Lower Extremity Muscle ◽  
Prolonged Duration ◽  
The Mean ◽  
The Impact

Background: Occupational footwear and a prolonged duration of walking have been previously reported to play a role in maintaining postural stability. The purpose of this paper was to analyze the impact of three types of occupational footwear: the steel-toed work boot (ST), the tactical work boot (TB), and the low-top work shoe (LT) on previously unreported lower extremity muscle activity during postural stability tasks. Methods: Electromyography (EMG) muscle activity was measured from four lower extremity muscles (vastus medialis (VM), medial hamstrings (MH), tibialis anterior (TA), and medial gastrocnemius (MG) during maximal voluntary isometric contractions (MVIC) and during a sensory organization test (SOT) every 30 min over a 4 h simulated workload while wearing ST, TB, and LT footwear. The mean MVIC and the mean and percentage MVIC during each SOT condition from each muscle was analyzed individually using a repeated measures ANOVA at an alpha level of 0.05. Results: Significant differences (p < 0.05) were found for maximal exertions, but this was limited to only the time main effect. No significant differences existed for EMG measures during the SOT. Conclusion: The findings suggest that occupational footwear type does not influence lower extremity muscle activity during both MVIC and SOT. Significantly lower muscle activity during maximal exertions over the course of the 4 h workload was evident, which can be attributed to localized muscular fatigue, but this was not sufficient to impact muscle activity during postural stability tasks.

Effects of an antioxidant vitamin mixture on lipid peroxidation at rest and postexercise

1993 ◽  
Vol 74 (2) ◽  
pp. 965-969 ◽  
Author(s):  
M. M. Kanter ◽  
L. A. Nolte ◽  
J. O. Holloszy
Keyword(s):  
Lipid Peroxidation ◽  
Beta Carotene ◽  
Alpha Tocopherol ◽  
Treadmill Running ◽  
Antioxidant Vitamin ◽  
Before And After ◽  
Antioxidant Supplement ◽  
Exercise Induced ◽  
Pentane Production ◽  
Vitamin Mixture

We studied the effects of ingesting an antioxidant vitamin mixture for 6 wk on breath pentane and serum malondialdehyde (MDA) levels before and after exercise. Twenty young (mean age 25.0 +/- 2.9 yr) healthy males were randomly assigned to either an antioxidant vitamin group (daily doses of 592 mg of alpha-tocopherol equivalents, 1,000 mg of ascorbic acid, and 30 mg of beta-carotene) or a placebo group. Exercise consisted of 30 min of treadmill running at 60% of maximal O2 consumption (VO2max) followed by 5 min of running at a pace that elicited approximately 90% of VO2max. Blood and breath samples were collected immediately after the two exercise bouts. The antioxidant supplement did not prevent the exercise-induced increase in lipid peroxidation, as reflected by the rate of pentane production and the increase in serum MDA concentration. However, ingestion of the antioxidant vitamins did result in significantly lower resting and postexercise levels of expired pentane and serum MDA. We conclude that taking ascorbate, alpha-tocopherol, and beta-carotene in the amounts used in this study serves to lower markers of lipid peroxidation at rest and after exercise but does not prevent the exercise-induced increase in oxidative stress.

Anaerobic Capacity: A Maximal Anaerobic Running Test Versus the Maximal Accumulated Oxygen Deficit

1996 ◽  
Vol 21 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Neil S. Maxwell ◽  
Myra A. Nimmo
Keyword(s):  
Blood Lactate ◽  
Intermittent Exercise ◽  
Anaerobic Capacity ◽  
Capillary Blood ◽  
Treadmill Running ◽  
Oxygen Deficit ◽  
Blood Samples ◽  
Significant Difference ◽  
Accumulated Oxygen Deficit ◽  
Exercise Treadmill

The present investigation evaluates a maximal anaerobic running test (MART) against the maximal accumulated oxygen deficit (MAOD) for the determination of anaerobic capacity. Essentially, this involved comparing 18 male students performing two randomly assigned supramaximal runs to exhaustion on separate days. Post warm-up and 1, 3, and 6 min postexercise capillary blood samples were taken during both tests for plasma blood lactate (BLa) determination. In the MART only, blood ammonia (BNH3) concentration was measured, while capillary blood samples were additionally taken after every second sprint for BLa determination. Anaerobic capacity, measured as oxygen equivalents in the MART protocol, averaged 112.2 ± 5.2 ml∙kg−1∙min−1. Oxygen deficit, representing the anaerobic capacity in the MAOD test, was an average of 74.6 ± 7.3 ml∙kg−1. There was a significant correlation between the MART and MAOD (r =.83, p <.001). BLa values obtained over time in the two tests showed no significant difference, nor was there any difference in the peak BLa recorded. Peak BNH3 concentration recorded was significantly increased from resting levels at exhaustion during the MART. Key words: supramaximal intermittent exercise, treadmill running performance, blood lactate, ammonia

scholarly journals Lower extremity muscle activation during horizontal and uphill running

1997 ◽  
Vol 83 (6) ◽  
pp. 2073-2079 ◽  
Author(s):  
Mark A. Sloniger ◽  
Kirk J. Cureton ◽  
Barry M. Prior ◽  
Ellen M. Evans
Keyword(s):  
Lower Extremity ◽  
High Intensity ◽  
Muscle Activation ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Peak Oxygen Uptake ◽  
Lower Extremity Muscle ◽  
Or Groups ◽  
Exercise Induced ◽  
The Right

Sloniger, Mark A., Kirk J. Cureton, Barry M. Prior, and Ellen M. Evans. Lower extremity muscle activation during horizontal and uphill running. J. Appl. Physiol. 83(6): 2073–2079, 1997.—To provide more comprehensive information on the extent and pattern of muscle activation during running, we determined lower extremity muscle activation by using exercise-induced contrast shifts in magnetic resonance (MR) images during horizontal and uphill high-intensity (115% of peak oxygen uptake) running to exhaustion (2.0–3.9 min) in 12 young women. The mean percentage of muscle volume activated in the right lower extremity was significantly ( P <0.05) greater during uphill (73 ± 7%) than during horizontal (67 ± 8%) running. The percentage of 13 individual muscles or groups activated varied from 41 to 90% during horizontal running and from 44 to 83% during uphill running. During horizontal running, the muscles or groups most activated were the adductors (90 ± 5%), semitendinosus (86 ± 13%), gracilis (76 ± 20%), biceps femoris (76 ± 12%), and semimembranosus (75 ± 12%). During uphill running, the muscles most activated were the adductors (83 ± 8%), biceps femoris (79 ± 7%), gluteal group (79 ± 11%), gastrocnemius (76 ± 15%), and vastus group (75 ± 13%). Compared with horizontal running, uphill running required considerably greater activation of the vastus group (23%) and soleus (14%) and less activation of the rectus femoris (29%), gracilis (18%), and semitendinosus (17%). We conclude that during high-intensity horizontal and uphill running to exhaustion, lasting 2–3 min, muscles of the lower extremity are not maximally activated, suggesting there is a limit to the extent to which additional muscle mass recruitment can be utilized to meet the demand for force and energy. Greater total muscle activation during exhaustive uphill than during horizontal running is achieved through an altered pattern of muscle activation that involves increased use of some muscles and less use of others.

scholarly journals Does Emotion Regulation Predict Gains in Exercise-Induced Fitness? A Prospective Mixed-Effects Study with Elite Helicopter Pilots

2020 ◽  
Vol 17 (11) ◽  
pp. 4174
Author(s):  
David Cárdenas ◽  
Iker Madinabeitia ◽  
Francisco Alarcón ◽  
José C. Perales
Keyword(s):  
Emotion Regulation ◽  
Strong Predictor ◽  
Treadmill Running ◽  
Time To Exhaustion ◽  
Negative Urgency ◽  
Expressive Suppression ◽  
Helicopter Pilots ◽  
Before And After ◽  
Fitness Training ◽  
Exercise Induced

Emotion regulation (ER) is a strong predictor of different aspects of mental health and wellbeing. However, only recently has ER been examined in relation to physical activity and its effects on fitness. In the present study, 26 elite helicopter pilots, serving in the Spanish Air Force, were physically trained for 6 months, and their level of fitness (maximum oxygen consumption and time to exhaustion in a treadmill-running test) was assessed before and after that period. Additionally, two indices of emotion regulation (general adaptiveness of ER strategies, as measured by the Emotion Regulation Questionnaire (ERQ), and negative urgency, as measured by the UPPS-P questionnaire) measured at baseline were used as prospective predictors of fitness improvement. After controlling for individual features, baseline fitness, and type of training, better emotion regulation strategies (more cognitive reappraisal plus less expressive suppression) predicted larger fitness gains (p = 0.028). Incidental emotion regulation, as measured by the negative urgency index, failed to predict pre–post-fitness changes (p = 0.734). These results suggest that fostering emotion regulation skills may improve the effectiveness of fitness training programs.

Brachial artery flow-mediated dilation during handgrip exercise: evidence for endothelial transduction of the mean shear stimulus

2008 ◽  
Vol 294 (6) ◽  
pp. H2669-H2679 ◽  
Author(s):  
K. E. Pyke ◽  
V. Poitras ◽  
M. E. Tschakovsky
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Phase I ◽  
Brachial Artery ◽  
Muscle Activation ◽  
Flow Mediated Dilation ◽  
Stimulus Response ◽  
The Mean ◽  
Forearm Exercise ◽  
Exercise Induced

Exercise elevates shear stress in the supplying conduit artery. Although this is the most relevant physiological stimulus for flow-mediated dilation (FMD), the fluctuating pattern of shear that occurs may influence the shear stress-FMD stimulus response relationship. This study tested the hypothesis that the brachial artery FMD response to a step increase in shear is influenced by the fluctuating characteristics of the stimulus, as evoked by forearm exercise. In 16 healthy subjects, we examined FMD responses to step increases in shear rate in three conditions: stable shear upstream of heat-induced forearm vasodilation (FHStable); fluctuating shear upstream of heat-induced forearm vasodilation and rhythmic forearm cuff inflation/deflation (FHFluctuating); and fluctuating shear upstream of exercise-induced forearm vasodilation (FEStep Increase). The mean increase in shear rate (±SD) was the same in all trials (FHFluctuating: 51.69 ± 15.70 s−1; FHStable: 52.16 ± 14.10 s−1; FEStep Increase: 50.14 ± 13.03 s−1 P = 0.131). However, the FHFluctuating and FEStep Increase trials resulted in a fluctuating shear stress stimulus with rhythmic high and low shear periods that were 96.18 ± 24.54 and 11.80 ± 7.30 s−1, respectively. The initial phase of FMD (phase I) was followed by a second, delayed-onset FMD and was not different between conditions (phase I: FHFluctuating: 5.63 ± 2.15%; FHStable: 5.33 ± 1.85%; FEStep Increase: 5.30 ± 2.03%; end-trial: FHFluctuating: 7.76 ± 3.40%; FHStable: 7.00 ± 3.03%; FEStep Increase: 6.68 ± 3.04%; P = 0.196). Phase I speed also did not differ ( P = 0.685). In conclusion, the endothelium transduced the mean shear when exposed to shear fluctuations created by a typical handgrip protocol. Muscle activation did not alter the FMD response. Forearm exercise may provide a viable technique to investigate brachial artery FMD in humans.

scholarly journals Training muscle activation patterns of the lower paretic extremity using directional exertion improves mobility in persons with hemiparesis: a pilot study

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Daniel Bourbonnais ◽  
René Pelletier ◽  
Joëlle Azar ◽  
Camille Sille ◽  
Michel Goyette
Keyword(s):  
Lower Extremity ◽  
Muscle Activation ◽  
Force Feedback ◽  
Sagittal Plane ◽  
Gait Velocity ◽  
Static Force ◽  
Activation Patterns ◽  
Feedback Training ◽  
Muscle Activation Patterns ◽  
Before And After

Abstract Background Controlled static exertion performed in the sagittal plane on a transducer attached to the foot requires coordinated moments of force of the lower extremity. Some exertions and plantarflexion recruit muscular activation patterns similar to synergies previously identified during gait. It is currently unknown if persons with hemiparesis following stroke demonstrate similar muscular patterns, and if force feedback training utilizing static exertion results in improved mobility in this population. Methods Electromyographic (EMG) activity of eight muscles of the lower limb were recorded using surface electrodes in healthy participants (n = 10) and in persons with hemiparesis (n = 8) during an exertion exercise (task) performed in eight directions in the sagittal plane of the foot and a plantarflexion exercise performed at 20 and 40% maximum voluntary effort (MVE). Muscle activation patterns identified during these exertion exercises were compared between groups and to synergies reported in the literature during healthy gait using cosine similarities (CS). Functional mobility was assessed in four participants with hemiparesis using GAITRite® and the Timed Up and Go (TUG) test at each session before, during and after static force feedback training. Tau statistics were used to evaluate the effect on mobility before and after training. Measures of MVE and the accuracy of directional exertion were compared before and after training using ANOVAs. Spearman Rho correlations were also calculated between changes in these parameters and changes in mobility before and after the training. Results Muscle activation patterns during directional exertion and plantarflexion were similar for both groups of participants (CS varying from 0.845 to 0.977). Muscular patterns for some of the directional and plantarflexion were also similar to synergies recruited during gait (CS varying from 0.847 to 0.951). Directional exertion training in hemiparetic subjects resulted in improvement in MVE (p < 0.040) and task performance accuracy (p < 0.001). Hemiparetic subjects also demonstrated significant improvements in gait velocity (p < 0.032) and in the TUG test (p < 0.022) following training. Improvements in certain directional efforts were correlated with changes in gait velocity (p = 0.001). Conclusion Static force feedback training following stroke improves strength and coordination of the lower extremity while recruiting synergies reported during gait and is associated with improved mobility.

Quantification of ultrastructural damage in human skeletal muscle

1991 ◽  
Vol 49 ◽  
pp. 126-127
Author(s):  
T. G. Manfredi ◽  
W. Ding ◽  
W. J. Evans ◽  
R. A. Fielding ◽  
J. G. Cannon ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Damage ◽  
Microscopic Analysis ◽  
Treadmill Running ◽  
Sensitive Information ◽  
Young Males ◽  
Cacodylate Buffer ◽  
Before And After ◽  
Cellular Markers ◽  
Exercise Induced

Qualitative microscopic analysis of muscle architecture provides information about cellular markers of muscle fiber disruption in myopathic, aging, and experimentally damaged muscle. However, this approach does not provide sensitive information regarding the extent of muscle damage and has serious limitations when research protocols address tissue remodeling. The purpose of this study was to quantitatively assess the extent of muscle damage in young and older adults before and after exercise-induced damage. The older adults in this study had lower aerobic capacities and muscle mass than their younger counterparts, suggesting greater vulnerability toward muscle damage produced by physiologic stress.Five young males, ages 20 to 29 years and five older males, age 60 to 75 years had percutaneous needle biopsies taken from the vastis lateralis muscle before and after (N=9) exercise consisting of reverse cycling or downhill treadmill running at a prescribed physiologic effort. Muscle samples were prefixed in 3.0% gluteraldehyde in cacodylate buffer and post-fixed in VL OSO4. This was followed by routine procedures for TEM.

Development of Race Profiles for the Performance of a Simulated 2000-m Rowing Race

2003 ◽  
Vol 28 (4) ◽  
pp. 536-546 ◽  
Author(s):  
Michael D. Kennedy ◽  
Gordon J. Bell
Keyword(s):  
Critical Power ◽  
Elite Athletes ◽  
Maximal Oxygen Consumption ◽  
Oxygen Deficit ◽  
Male And Female ◽  
Pacing Strategy ◽  
Accumulated Oxygen Deficit ◽  
Before And After ◽  
The Mean ◽  
And Gender

The purpose of this study was to determine the race profile for a 2000-m simulated rowing race as well as the effect of training and gender on the race profile. Nineteen men and 19 women undertook a 2000-m simulated rowing race before and after 10 weeks of a typical off-season training program for rowing. Velocity was calculated every 200 m and the deviation in velocities from the mean race velocity (MRV) was plotted every 200 m to produce race profiles for each gender before and after training. The three fastest male rowers varied approximately 0.02 m•s−1 from the MRV after training and displayed a constant-pace model. The fastest female rowers displayed an all-out strategy after training, producing large deviations from MRV. Average squared deviations from the mean (SDM) determined that all groups except the fastest females had a reduction in MRV deviation after training. These results suggest that the optimal race profile for a simulated 2000-m rowing race may be different between genders. Training reduces SDM and influences both male and female pacing patterns such that both exhibit a pacing strategy that is more similar to that of elite athletes in other events of similar and shorter duration. Key words: maximal oxygen consumption, critical power, pacing strategy, critical velocity, accumulated oxygen deficit

Variability in the interpolated twitch torque for maximal and submaximal voluntary contractions

2003 ◽  
Vol 95 (4) ◽  
pp. 1648-1655 ◽  
Author(s):  
M. A. E. Oskouei ◽  
B. C. F. van Mazijk ◽  
M. H. C. Schuiling ◽  
W Herzog
Keyword(s):  
Muscle Activation ◽  
Knee Extensor ◽  
Voluntary Contraction ◽  
Twitch Force ◽  
Actual Force ◽  
Before And After ◽  
Target Force ◽  
The Mean ◽  
Voluntary Contractions ◽  
Maximal Effort

The superimposed twitch technique is frequently used to study the degree of motor unit activation during voluntary effort. This technique is one of the preferred methods to determine the activation deficit (AD) in normal, athletic, and patient populations. One of the limitations of the superimposed twitch technique is its variability under given contractile conditions. The objective of this research was to determine the source(s) of variability in the superimposed twitch force (STF) for repeat measurements. We hypothesized that the variability in the AD measurements may be caused by the timing of the twitch force relative to the onset of muscle activation, by force transients during the twitch application, by small variations in the actual force from the nominal target force, and by variations in the resting twitch force. Twenty-eight healthy subjects participated in this study. Sixteen of these subjects participated in a protocol involving contractions at 50% of their maximal voluntary contraction (MVC) effort, whereas the remaining 12 participated in a protocol involving contractions at 100% of their MVC. Doublet-twitch stimuli were superimposed onto the 50 and 100% effort knee extensor muscle contractions, and the resting twitch forces, voluntary knee extensor forces, and STFs were then measured. The mean resting twitch forces obtained before and after 8 s of 50% of MVC were the same. Similarly, the mean STFs determined at 1, 3, 5, and 7 s into the 50% MVC were the same. The variations in twitch force were significantly smaller after accounting for the actual force at twitch application than those calculated from the prescribed forces during the 50% MVC protocol ( P < 0.05). Furthermore, the AD and the actual force showed statistically significant negative correlations for the 50% MVC tests. The interpolated twitch torque determined for the maximal effort contractions ranged from 1 to 70%. In contrast to the protocol at 50% of MVC, negative correlations were only observed in 5 of the 12 subjects during the 100% effort contractions. These results suggest that small variations in the actual force from the target force can account for the majority of the variations in the STFs for submaximal but not maximal effort contractions. For the maximal effort contractions, large variations in the STF exist due to undetermined causes.

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