Intermittent exercise alters endurance in an eight-legged ectotherm

1992 ◽  
Vol 262 (5) ◽  
pp. R852-R859 ◽  
Author(s):  
R. B. Weinstein ◽  
R. J. Full

Most animals move intermittently, yet many proposed performance limitations of terrestrial locomotion are based on steady-state measurements and assumptions. We examined the effect of work-rest transitions by exercising the ghost crab, Ocypode quadrata (28.1 +/- 8.1 g), intermittently on a treadmill at 0.30 m/s, a supramaximal speed [i.e., greater than the speed that elicits the maximal rate of oxygen consumption (VO2)]. Duration of the exercise and pause periods, ratio of exercise to pause, and speed during the exercise period were varied to determine the effect on performance. Crabs fatigued after 7.5 min of continuous running, a distance capacity (i.e., total distance traveled before fatigue) of 135 m. When the task was done intermittently with 2-min exercise and 2-min pause periods, the crabs fatigued after 87 min (a total distance of 787 m), representing an 5.8-fold increase in distance capacity compared with continuous exercise at the same absolute speed (0.30 m/s) and a 2.2-fold increase in distance capacity compared with continuous exercise at the same average speed (0.15 m/s). Pause periods less than 30 s did not result in greater distance capacity compared with continuous exercise at the same average speed. Longer (3-5 min) and shorter exercise periods (less than or equal to 30 s) decreased distance capacity. Leg muscle lactate increased 10-fold to 15 mumol/g leg during intermittent exercise. However, significant amounts of lactate were cleared from the leg during the brief pause periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Author(s):  
Wajdi Souissi ◽  
Mohamed Amine Bouzid ◽  
Mohamed Amine Farjallah ◽  
Lobna Ben Mahmoud ◽  
Mariem Boudaya ◽  
...  

The aim of this study was to examine the effect of running exercise modality on oxidative stress. Thirteen endurance athletes (age: 21.46 ± 0.66 years) performed three different running exercise modalities (Continuous running exercise (CR): continuous running exercise at 75% of VO2max for 25 min; intermittent running exercise #1 (15/15): intermittent running protocol, 15 s running at 75% of VO2max, 15 s passive recovery, performed for 50 min; intermittent running exercise #2 (30/30): intermittent running protocol, 30 s running at 75% of VO2max, 30 s passive recovery, performed for 50 min) in a randomized order. Blood samples were drawn at rest and immediately after each running exercise and assessed for malondialdehyde (MDA), advanced oxidation protein products (AOPP), superoxide dismutase(SOD), and glutathione peroxidase (GPX) activities. MDA increased by 55% following 30/30 exercise (p < 0.01), while it remained unchanged with CR and15/15 exercise. SOD increased after CR (+13.9%, p < 0.05), and also remained unchanged after 15/15 (p > 0.05) and decreased after 30/30 (−19.7% p < 0.05). GPX and AOPP did not change after exercise in all experimental sessions (p > 0.05). In conclusion, 30/30 intermittent running induced higher lipid damages than the 15/15 and CR exercise. 15/15 intermittent exercise promoted a better balance between free radicals production and antioxidant defense compared to continuous exercise and intermittent 30/30 exercise.


Author(s):  
Umile Giuseppe Longo ◽  
Francesco Sofi ◽  
Vincenzo Candela ◽  
Laura Risi Ambrogioni ◽  
Giuditta Pagliai ◽  
...  

Abstract Background Our previous study on the 2016/2017 Serie A season showed that a greater likelihood of reaching the top positions in the Italian league “Serie A” seemed to be mainly related to sprint activity, goal attempts, total throws, target shots and assists. Therefore, we aim to evaluate the following season data in the same league to compare, confirm, and improve these results. Methods The data of all the matches played during the “Serie A” 2017–2018 season were obtained from the Italian soccer league. The teams’ analysis was performed in terms of total distance covered in km, jogging, running and sprint activities, average speed, and match statistics (total shots, shots on target, goal attempts, assists, turnovers, and steals). Results Teams that reached the first four positions revealed a lower percentage of running (65.98 ± 1.51 vs. 66.84 ± 2.18; p < 0.001), a higher percentage of jogging (25.61 ± 1.71 vs. 25.30 ± 1.97; p = 0.037) and sprint activities (8.41 ± 1.04 vs. 7.86 ± 0.82; p < 0.001). Match statistics seem to be statistically different between the first four teams the other teams. The total goals are strongly associated both with the total score at the end of the championship (R = 0.906; p < 0.001) and with the position in the final ranking (R = 0.850; p < 0.001). Conclusions Our results suggest that high-level teams have a lower running rate and a higher percentage of jogging and sprinting than other teams.


Sports ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 98 ◽  
Author(s):  
Muzaffer Colakoglu ◽  
Ozgur Ozkaya ◽  
Gorkem Balci

Cardiovascular drift (CV-Drift) may occur after the ~10th min of submaximal continuous exercising. The purpose of this study was to examine whether CV-Drift is prevented by an intermittent exercise modality, instead of a continuous exercise. Seven well-trained male cyclists volunteered to take part in the study ( V ˙ O2max: 61.7 ± 6.13 mL·min−1·kg−1). Following familiarization sessions, athletes’ individual maximal O2 consumption ( V ˙ O2max), maximum stroke volume responses (SVmax), and cardiac outputs (Qc) were evaluated by a nitrous-oxide re-breathing system and its gas analyzer. Then, continuous exercises were performed 30 min at cyclists’ 60% V ˙ O2max, while intermittent exercises consisted of three 10 min with 1:0.5 workout/recovery ratios at the same intensity. Qc measurements were taken at the 5th, 9th, 12nd, 15th, 20th, 25th, and 30th min of continuous exercises versus 5th and 10th min of workout phases of intermittent exercise modality. Greater than a 5% SV decrement, with accompanying HR, increase, while Qc remained stable and was accepted as CV-Drift criterion. It was demonstrated that there were greater SV responses throughout intermittent exercises when compared to continuous exercises (138.9 ± 17.9 vs. 144.5 ± 14.6 mL, respectively; p ≤ 0.05) and less HR responses (140.1 ± 14.8 vs. 135.2 ± 11.6 bpm, respectively; p ≤ 0.05), while mean Qc responses were similar (19.4 ± 2.1 vs. 19.4 ± 1.5 L, respectively; p > 0.05). Moreover, the mean times spent at peak SV scores of exercise sessions were greater during intermittent exercise (1.5 vs. 10 min) (p < 0.001). In conclusion, intermittent exercises reduce CV-Drift risk and increases cardiac adaptation potentials of exercises with less physiological stress.


1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.


1988 ◽  
Vol 255 (3) ◽  
pp. R513-R519 ◽  
Author(s):  
G. P. Dobson ◽  
W. S. Parkhouse ◽  
J. M. Weber ◽  
E. Stuttard ◽  
J. Harman ◽  
...  

The aim of this study was to examine some metabolic properties and changes that occur in skeletal muscle and blood of greyhounds after an 800-m sprint. Three prime moving fast-twitch muscles were selected: biceps femoris (BF), gastrocnemius (G), and vastus lateralis (VL). The amount of glycogen utilized during the event was 42.57, 43.86, and 42.73 mumol glucosyl units/g wet wt, respectively. Expressed as a function of race time (48.3 +/- 0.7 s, n = 3), the mean rate of glycogen breakdown was 53.48 +/- 0.5 mumol.g wet wt-1.min-1 during the sprint. This is equivalent to an ATP turnover of 160 mumol.g wet wt-1.min-1, assuming 100% anaerobic conversion to lactate. This represents a conservative estimate, since greyhound muscle is heterogeneous and comprised of a large percentage of fast-twitch oxidative fibers (Armstrong et al., Am. J. Anat. 163: 87-98, 1982). The large decrease in muscle glycogen was accompanied by a 6- to 7-fold increase in muscle lactate from 3.48 +/- 0.13 to 25.42 +/- 3.54 (BF), 2.54 +/- 1.05 to 18.96 +/- 2.60 (G), and 4.57 +/- 0.44 to 30.09 +/- 1.94 mumol.g wet wt (VL), and a fall in muscle pH from 6.88 +/- 0.03 to 6.40 +/- 0.02 (BF), 6.92 +/- 0.02 to 6.56 +/- 0.02 (G), and 6.93 +/- 0.02 to 6.47 +/- 0.01 (VL). Cytosolic phosphorylation potential in BF decreased 10-fold from 11,360 +/- 680 to 1,184 +/- 347, and redox potential decreased 5-fold, indicating a marked reduction in the cytosol at this time.(ABSTRACT TRUNCATED AT 250 WORDS)


1976 ◽  
Vol 231 (3) ◽  
pp. 766-771 ◽  
Author(s):  
TE Graham ◽  
DG Sinclair ◽  
CK Chapler

The concentration of several metabolic intermediates, blood flow (Q), oxygen uptake (VO2), and lactate release (La) were measured in the gastrocnemius muscle of anesthetized dogs. Muscle lactate concentration increased from 1.6 to 2.7 mumol/g wet wt (P less than 0.05) during 0.5-5 min of contractions at 5 twitches/s but was not different from the contralateral resting muscle at 15, 30, or 60 min. Glycerophosphate increased from 0.35 to 0.70 mumol/g wet wt (P less than 0.05) during 0.5-5 min of activity, whereas muscle pyruvate decreased from 0.09 to 0.07 mumol/g wet wt (P less than 0.05). The concentration of NAD did not change in 9 of 11 experiments during contractions, despite a 12- to 15-fold increase in La. Significant decreases in NAD were observed when Q was compromised by arterial occlusion during contractions. No demonstrable relationship existed between La and either the muscle lactate concentration or muscle-venous lactate concentration gradient. Q was positively correlated with both La and muscle lactate during the first 5-15 min of activity. We conclude that increased La or increased lactate concentration in muscle need not be associated with hypoxia and that Q has a major influence on La.


2008 ◽  
Vol 294 (2) ◽  
pp. R594-R600 ◽  
Author(s):  
H. J. Green ◽  
T. A. Duhamel ◽  
G. P. Holloway ◽  
J. W. Moule ◽  
D. W. Ranney ◽  
...  

In this study, we have investigated the hypothesis that an exercise protocol designed to repeatedly induce a large dependence on carbohydrate and large increases in glycolytic flux rate would result in rapid increases in the principal glucose and lactate transporters in working muscle, glucose transporter (GLUT)-4 and monocarboxylate transporter (MCT)4, respectively, and in activity of hexokinase (Hex), the enzyme used to phosphorylate glucose. Transporter abundance and Hex activity were assessed in homogenates by Western blotting and quantitative chemiluminescence and fluorometric techniques, respectively, in samples of tissue obtained from the vastus lateralis in 12 untrained volunteers [peak aerobic power (V̇o2peak) = 44.3 ± 2.3 ml·kg−1·min−1] before cycle exercise at repetitions 1 (R1), 2 (R2), 9 (R9), and 16 (R16). The 16 repetitions of the exercise were performed for 6 min at ∼90% V̇o2peak, once per hour. Compared with R1, GLUT-4 increased ( P < 0.05) by 28% at R2 and remained elevated ( P < 0.05) at R9 and R16. For MCT-4, increases ( P < 0.05) of 24% were first observed at R9 and persisted at R16. No changes were observed in GLUT-1 and MCT-1 or in Hex activity. The ∼17- to 24-fold increase ( P < 0.05) in muscle lactate observed at R1 and R2 was reduced ( P < 0.05) to an 11-fold increase at R9 and R16. It is concluded that an exercise protocol designed to strain muscle carbohydrate reserves and to result in large increases in lactic acid results in a rapid upregulation of both GLUT-4 and MCT-4.


1984 ◽  
Vol 56 (1) ◽  
pp. 145-149 ◽  
Author(s):  
H. J. Green ◽  
J. A. Thomson ◽  
M. E. Ball ◽  
R. L. Hughson ◽  
M. E. Houston ◽  
...  

To investigate the role of high-intensity intermittent exercise on adaptations in blood volume and selected hematological measures, four male subjects aged 19–23 yr [peak O2 consumption (VO2max) = 53 ml X min-1 X kg-1] performed supramaximal (120% VO2max) cycle exercise on 3 consecutive days. Each exercise session consisted of intermittent work performed as bouts of 1-min work to 4-min rest until fatigue or until a maximum of 24 repetitions had been completed. Measurements on blood samples were made before the exercise period and 24 h after the last exercise session. Plasma volume (PV) estimated using 131I-human serum albumin increased by 11.6% (3,504 vs. 3,912 ml; P less than 0.05). Total blood volume (TBV) based on PV and hematocrit (Hct) values increased by 4.5% (5,798 vs. 6,059 ml; P less than 0.05), whereas red cell volume (RCV) decreased by 6.4% (2,294 vs. 2,147 ml; P less than 0.05). Measurements of hematological indices indicated significant reductions (P less than 0.05) in whole-blood Hct (39.7 vs. 35.5%), hemoglobin concentration (15.5 vs. 13.9 g/100 ml), hemoglobin content (897 vs. 839 g), and red blood cell count (5.15 vs. 4.55 X 10(6) X mm-3). The findings of this study suggest that exercise intensity is a major factor in promoting exercise-induced hypervolemia and that rapid elevations in PV can be induced early in training.


1991 ◽  
Vol 70 (2) ◽  
pp. 726-731 ◽  
Author(s):  
R. W. Grange ◽  
M. E. Houston

Potential mechanisms of fatigue (metabolic factors) and potentiation (phosphate incorporation by myosin phosphorylatable light chains) were investigated during recovery from a 60-s maximal voluntary isometric contraction (MVC) in the quadriceps muscle of 12 subjects. On separate days before and for 2 h after the 60-s MVC, either a 1-s MVC or electrically stimulated contractions were used as indexes to test muscle performance. Torque at the end of the 60-s MVC was 57% of the initial level, whereas torques from a 1-s MVC and 50-Hz stimulation were most depressed in the immediate recovery period. At this time, muscle biopsy analyses revealed significant decreases in ATP and phosphocreatine and a 19-fold increase in muscle lactate. Conversely, isometric twitch torque and torque from a 10-Hz stimulus were the least depressed of six contractile indexes and demonstrated potentiation of 25 and 34%, respectively, by 4 min of recovery (P less than 0.05). At this time, muscle lactate concentration was still 16 times greater than at rest. An increased phosphate content of the myosin phosphorylatable light chains (P less than 0.05) was also evident both immediately and 4 min after the 60-s MVC. We conclude that the 60-s MVC produced marked force decreases likely due to metabolic displacement, while the limited decline in the twitch and 10-Hz torques and their significant potentiation suggested that myosin phosphorylation may provide a mechanism to enhance contractile force under conditions of submaximal activation during fatigue.


2012 ◽  
Vol 37 (6) ◽  
pp. 1047-1053 ◽  
Author(s):  
Talita Grossl ◽  
Ricardo Dantas de Lucas ◽  
Kristopher Mendes de Souza ◽  
Luiz Guilherme Antonacci Guglielmo

The maximal lactate steady state (MLSS) represents a submaximal intensity that may be important in prescribing both continuous and interval endurance training. This study compared time to exhaustion (TTE) at MLSS in continuous and intermittent (i.e., with pauses) exercise, investigating whether physiological variables differ between these exercise modes. Fourteen trained male cyclists volunteered for this investigation and performed an incremental test, several 30-min tests to determine two MLSS intensities (continuous and discontinuous protocol), and two randomized tests until exhaustion at MLSS intensities on a cycle ergometer. The intermittent or discontinuous protocol was performed using 5 min of cycling, with an interval of 1 min of passive rest. TTE at intermittent MLSS was 24% longer than TTE at continuous exercise (67.8 ± 14.3 min vs. 54.7 ± 10.9 min; p < 0.05; effect sizes = 1.04), even though the absolute power output of intermittent MLSS was higher than continuous (268 ± 29 W vs. 251 ± 29 W; p < 0.05). Additionally, the total mechanical work done was significantly lower at continuous exercise than at intermittent exercise. Likewise, regarding cardiorespiratory and metabolic variables, we observed greater responses during intermittent exercise than during continuous exercise at MLSS. Thus, for endurance training prescription, this is an important finding to apply in extensive interval sessions at MLSS. This result suggests that interval sessions at discontinuous MLSS should be used instead of continuous MLSS, as discontinuous MLSS allows for a larger amount of total work during the exhaustion trial.


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