scholarly journals Peripheral Alterations Affect the Loss in Force after a Treadmill Downhill Run

2021 ◽  
Vol 18 (15) ◽  
pp. 8135
Author(s):  
Nicola Giovanelli ◽  
Mirco Floreani ◽  
Filippo Vaccari ◽  
Stefano Lazzer
Keyword(s):  
Maximal Oxygen Consumption ◽  
Single Pulse ◽  
Voluntary Contraction ◽  
Muscle Contractility ◽  
Downhill Running ◽  
Torque Response ◽  
Before And After ◽  
Exercise Muscle ◽  
Exercise Induced ◽  
Trail Running

Downhill running has an important effect on performance in trail running competitions, but it is less studied than uphill running. The purpose of this study was to investigate the cardiorespiratory response during 15 minutes of downhill running (DR) and to evaluate the neuromuscular consequences in a group of trail runners. Before and after a 15-min DR trial (slope: −25%) at ~60% of maximal oxygen consumption (V̇O2max), we evaluated maximal voluntary contraction torque (MVCt) and muscle contractility in a group of seventeen trail running athletes. Additionally, during the DR trial, we measured V̇O2 and heart rate (HR). V̇O2 and HR increased as a function of time, reaching +19.8 ± 15.9% (p < 0.001; ES: 0.49, medium) and +15.3 ± 9.9% (p < 0.001; ES: 0.55, large), respectively, in the last minute of DR. Post-exercise, the MVCt decreased (−22.2 ± 12.0%; p < 0.001; ES = 0.55, large) with respect to the pre-exercise value. All the parameters related to muscle contractility were impaired after DR: the torque evoked by a potentiated high frequency doublet decreased (−28.5 ± 12.7%; p < 0.001; ES: 0.61, large), as did the torque response from the single-pulse stimulation (St, −41.6 ± 13.6%; p < 0.001; ES: 0.70, large) and the M-wave (−11.8 ± 12.1%; p < 0.001; ES: 0.22, small). We found that after 15 min of DR, athletes had a decreased MVCt, which was ascribed mainly to peripheral rather than central alterations. Additionally, during low-intensity DR exercise, muscle fatigue and exercise-induced muscle damage may contribute to the development of O2 and HR drift.

scholarly journals Downhill Running: What Are The Effects and How Can We Adapt? A Narrative Review

2020 ◽  
Vol 50 (12) ◽  
pp. 2083-2110
Author(s):  
Bastien Bontemps ◽  
Fabrice Vercruyssen ◽  
Mathieu Gruet ◽  
Julien Louis
Keyword(s):  
Exercise Duration ◽  
Voluntary Contraction ◽  
Narrative Review ◽  
Whole Body ◽  
Running Speed ◽  
Compression Garments ◽  
Downhill Running ◽  
Exercise Induced ◽  
And Function

AbstractDownhill running (DR) is a whole-body exercise model that is used to investigate the physiological consequences of eccentric muscle actions and/or exercise-induced muscle damage (EIMD). In a sporting context, DR sections can be part of running disciplines (off-road and road running) and can accentuate EIMD, leading to a reduction in performance. The purpose of this narrative review is to: (1) better inform on the acute and delayed physiological effects of DR; (2) identify and discuss, using a comprehensive approach, the DR characteristics that affect the physiological responses to DR and their potential interactions; (3) provide the current state of evidence on preventive and in-situ strategies to better adapt to DR. Key findings of this review show that DR may have an impact on exercise performance by altering muscle structure and function due to EIMD. In the majority of studies, EIMD are assessed through isometric maximal voluntary contraction, blood creatine kinase and delayed onset muscle soreness, with DR characteristics (slope, exercise duration, and running speed) acting as the main influencing factors. In previous studies, the median (25th percentile, Q1; 75th percentile, Q3) slope, exercise duration, and running speed were − 12% (− 15%; − 10%), 40 min (30 min; 45 min) and 11.3 km h−1 (9.8 km h−1; 12.9 km h−1), respectively. Regardless of DR characteristics, people the least accustomed to DR generally experienced the most EIMD. There is growing evidence to suggest that preventive strategies that consist of prior exposure to DR are the most effective to better tolerate DR. The effectiveness of in-situ strategies such as lower limb compression garments and specific footwear remains to be confirmed. Our review finally highlights important discrepancies between studies in the assessment of EIMD, DR protocols and populations, which prevent drawing firm conclusions on factors that most influence the response to DR, and adaptive strategies to DR.

Vitamin B6 Deficiency can Reduce Fuel Storage and Utilization in Physically Trained Rats

2008 ◽  
Vol 78 (2) ◽  
pp. 64-69 ◽  
Author(s):  
Choi ◽  
Cho
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Muscle Protein ◽  
Plasma Free Fatty Acid ◽  
Vitamin B ◽  
Liver Protein ◽  
Protein Levels ◽  
Before And After ◽  
Fuel Storage ◽  
Exercise Muscle

This study investigated the effect of vitamin B6 deficiency on the utilization and recuperation of stored fuel in physically trained rats. 48 rats were given either vitamin B6-deficient (B6–) diet or control (B6+) diet for 4 weeks and were trained on treadmill for 30 minutes daily. All animals were then subdivided into 3 groups: before-exercise (BE); during-exercise (DE); after-exercise (AE). The DE group was exercised on treadmill for 1 hour just before being sacrificed. Animals in the AE group were allowed to take a rest for 2 hours after being exercised like the DE group. Glucose and free fatty acids were compared in plasma. Glycogen and triglyceride were compared in liver and skeletal muscle. Protein levels were compared in plasma, liver, and skeletal muscle. Compared with the B6+ group, plasma glucose levels of the B6– group were significantly lower before and after exercise. Muscle glycogen levels of the B6– group were significantly lower than those of the B6+ group regardless of exercise. The liver glycogen level of the B6– group was also significantly lower than that of B6+ group during and after exercise. Before exercise, plasma free fatty acid levels were not significantly different between the B6+ and B6– groups, and plasma free fatty acid levels of the B6– group were significantly lower during and after exercise. The muscle triglyceride level of the B6– group was significantly lower than that of the B6+ group before exercise, and there were no differences between B6+ and B6– groups during and after exercise. Liver triglyceride levels were not significantly different between B6+ and B6– groups. Plasma protein levels of the B6– group were lower than those of B6+ before and after exercise. Muscle protein levels of the B6– group were not significantly different from those of the B6+ group. Liver protein levels of the B6– group were significantly lower than that of the B6+ group after exercise. Liver protein levels of both B6+ and B6– groups were not significantly changed, regardless of exercise. Thus, it is suggested that vitamin B6 deficiency may reduce fuel storage and utilization with exercise in physically trained rats.

scholarly journals Cardiac Rehabilitation and Physical Performance in Patients after Myocardial Infarction: Preliminary Research

2021 ◽  
Vol 10 (11) ◽  
pp. 2253
Author(s):  
Agnieszka Grochulska ◽  
Sebastian Glowinski ◽  
Aleksandra Bryndal
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Rehabilitation ◽  
Physical Performance ◽  
Stress Test ◽  
Maximal Oxygen Consumption ◽  
Exercise Stress Test ◽  
Health Condition ◽  
Exercise Stress ◽  
Test Time ◽  
Before And After

(1) Background: Cardiovascular diseases, in particular, myocardial infarction (MI), are the main threats to human health in modern times. Cardiac rehabilitation (CR), and especially increased physical activity, significantly prevent the consequences of MI. The aim of this study was to assess physical performance in patients after MI before and after CR. (2) Methods: 126 patients after MI were examined. They were admitted to the cardiac rehabilitation ward twice: in the 3rd month after MI, and then in the 6th month after the last rehabilitation session. CR lasted 20 treatment days (4 weeks with 5 treatment days and 2 days’ break). The exercise stress test on the treadmill and a 6-minute walk test (6MWT) were used to assess physical performance. Patients were assigned to an appropriate rehabilitation model due to their health condition. (3) Results: In the studied group, the exercise stress test time and the metabolic equivalent of task (MET), the maximal oxygen consumption (VO2max), and 6MWT score increased significantly (p = 0.0001) at two time-points of observation. (4) Conclusion: CR significantly improves physical performance in patients after MI.

scholarly journals Insights into the combination of neuromuscular electrical stimulation and motor imagery in a training-based approach

2021 ◽  
Author(s):  
Amandine Bouguetoch ◽  
Alain Martin ◽  
Sidney Grosprêtre
Keyword(s):  
Electrical Stimulation ◽  
Motor Imagery ◽  
Neural Plasticity ◽  
Neuromuscular Electrical Stimulation ◽  
Voluntary Contraction ◽  
Muscle Architecture ◽  
Fascicle Length ◽  
Before And After ◽  
V Wave ◽  
And Control

Abstract Introduction Training stimuli that partially activate the neuromuscular system, such as motor imagery (MI) or neuromuscular electrical stimulation (NMES), have been previously shown as efficient tools to induce strength gains. Here the efficacy of MI, NMES or NMES + MI trainings has been compared. Methods Thirty-seven participants were enrolled in a training program of ten sessions in 2 weeks targeting plantar flexor muscles, distributed in four groups: MI, NMES, NMES + MI and control. Each group underwent forty contractions in each session, NMES + MI group doing 20 contractions of each modality. Before and after, the neuromuscular function was tested through the recording of maximal voluntary contraction (MVC), but also electrophysiological and mechanical responses associated with electrical nerve stimulation. Muscle architecture was assessed by ultrasonography. Results MVC increased by 11.3 ± 3.5% in NMES group, by 13.8 ± 5.6% in MI, while unchanged for NMES + MI and control. During MVC, a significant increase in V-wave without associated changes in superimposed H-reflex has been observed for NMES and MI, suggesting that neural adaptations occurred at supraspinal level. Rest spinal excitability was increased in the MI group while decreased in the NMES group. No change in muscle architecture (pennation angle, fascicle length) has been found in any group but muscular peak twitch and soleus maximal M-wave increased in the NMES group only. Conclusion Finally, MI and NMES seem to be efficient stimuli to improve strength, although both exhibited different and specific neural plasticity. On its side, NMES + MI combination did not provide the expected gains, suggesting that their effects are not simply cumulative, or even are competitive.

scholarly journals Physical activity and health, novel concepts and new targets: report from the 12th Conference of the International Research Group on the Biochemistry of Exercise

2004 ◽  
Vol 63 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Matthijs K. C. Hesselink ◽  
Marleen A. van Baak
Keyword(s):  
Physical Activity ◽  
Skeletal Muscle ◽  
Physical Exercise ◽  
Health Effects ◽  
Research Group ◽  
International Research ◽  
Biochemical Basis ◽  
International Research Group ◽  
Exercise Muscle ◽  
Exercise Induced

The present paper is the introductory paper to a series of brief reviews representing the proceedings of a recent conference on ‘The biochemical basis for the health effects of exercise’ organized by the International Research Group on the Biochemistry of Exercise in conjunction with the Nutrition Society. Here the aim is to briefly review and highlight the main innovations presented during this meeting. The following topics were covered during the meeting: exercise signalling pathways controlling fuel oxidation during and after exercise; the fatty acid transporters of skeletal muscle; mechanisms involved in exercise-induced mitochondrial biogenesis in skeletal muscle; new methodologies and insights in the regulation of fat metabolism during exercise; muscle hypertrophy: the signals of insulin, amino acids and exercise; adipose tissue–liver–muscle interactions leading to insulin resistance. In these symposia state-of-the-art knowledge on how physical exercise exerts its effects on health was presented. The fast-growing number of identified pathways and processes involved in the health effects of physical exercise, which were discussed during the meeting, will help to develop tailored physical-activity regimens in the prevention of inactivity-induced deterioration of health.

scholarly journals Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers

1996 ◽  
Vol 81 (5) ◽  
pp. 1901-1907 ◽  
Author(s):  
Roland Favier ◽  
Esperanza Caceres ◽  
Laurent Guillon ◽  
Brigitte Sempore ◽  
Michel Sauvain ◽  
...  
Keyword(s):  
Heart Rate ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Metabolic Responses ◽  
Physiological Data ◽  
Respiratory Gas Exchange ◽  
Gum Chewing ◽  
Arterial Blood ◽  
Before And After ◽  
Exercise Induced

Favier, Roland, Esperanza Caceres, Laurent Guillon, Brigitte Sempore, Michel Sauvain, Harry Koubi, and Hilde Spielvogel. Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers. J. Appl. Physiol. 81(5): 1901–1907, 1996.—To determine the effects of acute coca use on the hormonal and metabolic responses to exercise, 12 healthy nonhabitual coca users were submitted twice to steady-state exercise (∼75% maximal O2 uptake). On one occasion, they were asked to chew 15 g of coca leaves 1 h before exercise, whereas on the other occasion, exercise was performed after 1 h of chewing a sugar-free chewing gum. Plasma epinephrine, norepinephrine, insulin, glucagon, and metabolites (glucose, lactate, glycerol, and free fatty acids) were determined at rest before and after coca chewing and during the 5th, 15th, 30th, and 60th min of exercise. Simultaneously to these determinations, cardiorespiratory variables (heart rate, mean arterial blood pressure, oxygen uptake, and respiratory gas exchange ratio) were also measured. At rest, coca chewing had no effect on plasma hormonal and metabolic levels except for a significantly reduced insulin concentration. During exercise, the oxygen uptake, heart rate, and respiratory gas exchange ratio were significantly increased in the coca-chewing trial compared with the control (gum-chewing) test. The exercise-induced drop in plasma glucose and insulin was prevented by prior coca chewing. These results contrast with previous data obtained in chronic coca users who display during prolonged submaximal exercise an exaggerated plasma sympathetic response, an enhanced availability and utilization of fat (R. Favier, E. Caceres, H. Koubi, B. Sempore, M. Sauvain, and H. Spielvogel. J. Appl. Physiol. 80: 650–655, 1996). We conclude that, whereas coca chewing might affect glucose homeostasis during exercise, none of the physiological data provided by this study would suggest that acute coca chewing in nonhabitual users could enhance tolerance to exercise.

scholarly journals Gender based EEG before and after acute bout of aerobic exercise

2014 ◽  
Vol 6 (2) ◽  
pp. 29-34
Author(s):  
Nirmala Limbu ◽  
Ramanjan Sinha ◽  
Meenakshi Sinha ◽  
Bishnu Hari Paudel
Keyword(s):  
Acute Exercise ◽  
Healthy Adult ◽  
Alpha Power ◽  
Medical Sciences ◽  
Acute Bout ◽  
Before And After ◽  
Eeg Changes ◽  
Gender Based ◽  
Exercise Induced ◽  
Almost All

Objective: We aimed to investigate how EEG frequency bands change in females in response to acute exercise compared to males.Methods: Consenting healthy adult females (n=15) & males (n=15) bicycled an ergometer at 50% HRmax for 20 min. EEG was recorded using 10-20 system from mid-frontal (F4 & F3), central (C4 & C3), parietal (P4 & P3), temporal (T4 & T3) & occipital (O2 & O1) regions. Exercise-induced EEG changes were compared between two sexes by Mann Whitney test. EEG power (μV2) is presented as median & interquartile range.Results: In females, as compared to males, resting right side delta, alpha, and beta activities were more in almost all recorded sites [delta: F4= 49.82 (44.23-63.56) vs. 35.5 (32.70-44.44), p < 0.001; etc], [alpha F4: 127.62 (112.89-149.03) vs. 49.36 (46.37-52.98), p < 0.001; etc], [beta F4= 18.96 (15.83-25.38)  vs. 14.77 (10.34-17.55), p < 0.05; C4= 21.16 (18.4-25.9) vs. 15.48 (9.66-19.40), p < 0.01; etc]. Similarly, females resting right theta activity was more in parietal [P4= 33.04 (25.1-42.41) vs. 22.3 (18.36-34.33), p < 0.05] & occipital [O2= 50.81 (30.64-66.8) vs. 26.85 (22.18-34.42), p < 0.001] regions than in males. They had similar picture on the left side also. The delta values of right alpha power was less in female in frontal [F4= -11.61 (-45.24 -3.64) vs. 9.48 (1.05-16.58), p < 0.01] and central [C4= -72 (-32.98-9.48) vs. 22.69 (13.03-33.05), p < 0.01] regions compared to males. Also, they had less delta values of left central alpha [C3= -8.32 (-32.65-6.1) vs. 16.5 (0.36-36.36), p < 0.01] and temporal beta [T3= -6.29 (-10.09- -1.49) vs. 1.24 (-0.84- 2.8), p < 0.001] power compared to males.Conclusion: At rest females may have high EEG powers in different bands. In response to acute exercise, they respond in reverse way as compared to males.DOI: http://dx.doi.org/10.3126/ajms.v6i2.11116Asian Journal of Medical Sciences Vol.6(2) 2015 30-35

Exercise-induced focal skeletal muscle fiber degeneration and capillary morphology

1989 ◽  
Vol 66 (6) ◽  
pp. 2857-2865 ◽  
Author(s):  
F. M. Peeze Binkhorst ◽  
H. Kuipers ◽  
J. Heymans ◽  
P. M. Frederik ◽  
D. W. Slaaf ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Cross Sections ◽  
Muscle Fibers ◽  
Basal Membrane ◽  
Cross Sectional ◽  
Male Wistar Rats ◽  
Muscle Water Content ◽  
Exercise Muscle ◽  
Exercise Induced

The relationship between exercise-induced focal muscle fiber degeneration and changes in capillary morphology was investigated in male Wistar rats. Untrained animals ran on a treadmill for 1 h at submaximal intensity and were killed 0, 6, or 24 h after running. Nonexercised rats served as controls. In situ perfused soleus muscles were prepared for electron microscopy. Micrographed cross sections were quantitatively analyzed for parameters indicative of capillary blood flow or transcapillary exchange. Capillary lumina were ovally rather than circularly shaped, and no indications for obstruction of blood flow at the capillary level were found. Endothelial cells and their organelles had a normal appearance in all groups. However, immediately after exercise, capillaries showed a decreased thickness of their endothelium and basal membrane, probably caused by dehydration. Six hours after exercise, muscle fibers were swollen (28% increase in cross-sectional area), resulting in a slightly increased diffusion distance. This fiber swelling was not associated with an increase in muscle water content, a finding for which no explanation could be found. Twenty-four hours after the animals ran, capillaries located near degenerated muscle fibers had an increased cross-sectional luminal area and an increased luminal circumference. This effect decreased gradually with increasing distance from the degenerated fiber area. The present morphometric results do not support the hypothesis that changes in capillary morphology primarily contribute to exercise-induced focal muscle fiber degeneration.

Effects of aerobic plus explosive power exercises on bone remodeling and bone mineral density in young men

2017 ◽  
Vol 43 (1) ◽  
pp. 40-48
Author(s):  
Veysi Çay ◽  
Gurbuz Buyukyazi ◽  
Cevval Ulman ◽  
Fatma Taneli ◽  
Yeliz Doğru ◽  
...  
Keyword(s):  
Maximal Oxygen Consumption ◽  
Exercise Program ◽  
Exercise Group ◽  
Risk Level ◽  
Control Group ◽  
Maximal Heart Rate ◽  
Mineral Density ◽  
Explosive Power ◽  
Before And After ◽  
And Control

AbstractObjectives:This study aims to examine effects of aerobic jogging and explosive power exercises on body composition, maximal oxygen consumption (MaxVOMaterials and methods:Thirty seven healthy males were divided into exercise group (EG, n=19) and control group (CG, n=18). EG completed 10 weeks of outdoor aerobic (jogging at 60–70% maximal heart rate reserve starting from 20 min steadily increasing up to 28 min) and explosive power exercises (in 2–3 sets, with maximum repetitions lasting 15 s), 3 times per week. All measurements were taken before and after the exercise program. BMD was measured via dual energy X-ray absorptiometry (DEXA).Results:Body mass index (p<0.001) significantly decreased; MaxVOConclusion:Performing our outdoor exercise program in spring months might have an important role in the significant increase (9 vs. 22 ng/mL) in mean vitamin D level, which reached above the fracture risk level of 20 ng/mL.

The Influence of Intermittent Fatigue Exercise on Early and Late Phases of Relaxation From Maximal Voluntary Contraction

1997 ◽  
Vol 22 (6) ◽  
pp. 573-584 ◽  
Author(s):  
Anna Jaskólska ◽  
Artur Jaskólski
Keyword(s):  
Relaxation Time ◽  
Relaxation Rate ◽  
Maximal Voluntary Contraction ◽  
Early Phase ◽  
Intermittent Exercise ◽  
Young Male ◽  
Voluntary Contraction ◽  
Hand Grip ◽  
Before And After ◽  
Late Relaxation Time

Twenty-two young male subjects were tested to estimate the behavior of the early and late phases of relaxation from a 3-s maximal voluntary contraction (MVC) under the influence of fatigue. Less demanding and more demanding protocols of intermittent hand grip exercise were used to fatigue muscle. Before and after fatigue, the early and late relaxation time, maximal relaxation rate, and half-relaxation time were measured. The results showed that during voluntary movement (a) the early phase of relaxation was independent of the mode of intermittent exercise and did not change significantly after fatigue; (b) the late relaxation time and absolute maximal relaxation rate were slower after both protocols, with the changes more pronounced following the more demanding protocol; and (c) the half-relaxation time and relative maximal relaxation rate were changed only in the more demanding protocol. It is concluded that unlike the relaxation following electrical stimulation of isolated muscle, the early phase of relaxation from voluntary contraction appears to be the most resistant to the type of intermittent fatiguing exercise used in the present study, whereas the late relaxation time was the most sensitive to this type of fatigue. Key words: hand grip exercise, late relaxation time, early relaxation time, half-relaxation time

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