Fatigue and recovery in children and adults during sustained contractions at 2 different submaximal intensities

2013 ◽  
Vol 38 (9) ◽  
pp. 953-959 ◽  
Author(s):  
Dimitrios Patikas ◽  
Alexandros Kansizoglou ◽  
Nikolaos Koutlianos ◽  
Craig A. Williams ◽  
Konstantinos Hatzikotoulas ◽  
...  
Keyword(s):  
Plantar Flexion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Random Order ◽  
Voluntary Contraction ◽  
Similar Extent ◽  
Fatigue Protocol ◽  
Before And After ◽  
Agonist And Antagonist ◽  
Baseline Values

The purpose of this study was to examine the effects of submaximal sustained contractions on fatigue and recovery properties in untrained prepubescent boys (n = 14) and men (n = 14). All participants performed, in random order, an isometric plantar flexion at 20% and 60% of their maximal voluntary contraction (MVC) until exhaustion (20%fatigue and 60%fatigue, respectively). During both fatigue protocols, surface electromyogram (sEMG) of the soleus and tibialis anterior muscles was recorded. Before and after the fatigue protocol, MVCs and blood lactate concentration were obtained. During 20%fatigue and 60%fatigue, agonist and antagonist sEMG increased gradually to a similar extent in both groups. Immediately after fatigue, MVC torque decreased in both groups, compared with prefatigue values, and boys recovered faster than men in both fatigue protocols. The reduction in agonist sEMG during MVC after fatigue was not significantly different between men and boys (p < 0.05), independent of the fatigue protocol. sEMG of boys recovered to baseline values 3 min after the 20%fatigue and 60%fatigue protocols, whereas men did not recover. Lactate concentration increased immediately after the end of the fatigue protocols, compared with the prefatigue values (p < 0.05). This increase was higher for the 60%fatigue than for 20%fatigue protocol, and did not differ between boys and men. It is concluded that low- and middle-intensity submaximal sustained isometric fatigue protocols induce similar fatigue effects in boys and men. Furthermore, it was shown that boys can recover faster than men, independent of the contraction intensity that induces fatigue.

scholarly journals Effects of Adding Small Combat Games to Regular Taekwondo Training on Physiological and Performance Outcomes in Male Young Athletes

2021 ◽  
Vol 12 ◽  
Author(s):  
Ibrahim Ouergui ◽  
Emerson Franchini ◽  
Hamdi Messaoudi ◽  
Hamdi Chtourou ◽  
Anissa Bouassida ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Random Order ◽  
Performance Outcomes ◽  
Rating Of Perceived Exertion ◽  
Control Group ◽  
Metabolic Demand ◽  
Before And After ◽  
Post Hoc

This study investigated the effect of area sizes (4 × 4, 6 × 6, and 8 × 8 m) and effort-pause ratios (free combat vs. 1:2) variation on the physiological and perceptive responses during taekwondo combats (Study 1). In a second study, the effects on physical performance of 8 weeks of small combat-based training added to regular taekwondo training were investigated (Study 2). In random order, 32 male taekwondo athletes performed six (i.e., two effort-to-pause ratios × three area sizes conditions) different 2-min taekwondo combats (Study 1). Thereafter (Study 2), they were randomly assigned to three experimental groups (4 × 4, 6 × 6, and 8 × 8 m) and an active control group (CG). Regarding Study 1, blood lactate concentration [La] before and after each combat, mean heart rate (HRmean) during each combat, and rating of perceived exertion (CR-10) immediately after each combat were assessed. Regarding Study 2, progressive specific taekwondo (PSTT) to estimate maximum oxygen consumption (VO2max), taekwondo-specific agility, and countermovement jump (CMJ) tests were administered before and after 8 weeks of training. Study 1 results showed that 4 × 4 m elicited lower HRmean values compared with 6 × 6 m (d = −0.42 [small], p = 0.030) and free combat induced higher values compared with the 1:2 ratio (d = 1.71 [large], p &lt; 0.001). For [La]post, 4 × 4 m area size induced higher values than 6 × 6 m (d = 0.99 [moderate], p &lt; 0.001) and 8 × 8 m (d = 0.89 [moderate], p &lt; 0.001) and free combat induced higher values than 1:2 ratio (d = 0.69 [moderate], p &lt; 0.001). Higher CR-10 scores were registered after free combat compared with 1:2 ratio (d = 0.44 [small], p = 0.007). For Study 2, VO2max increased after training [F(1, 56) =30.532, p &lt; 0.001; post-hoc: d = 1.27 [large], p &lt; 0.001] with higher values for 4 × 4 m compared with CG (d = 1.15 [moderate], p = 0.009). Agility performance improved after training [F(1, 56) = 4.419, p = 0.04; post-hoc: d = −0.46 [small], p = 0.04] and 4 × 4 m induced lower values in comparison with 6 × 6 m (d = −1.56 [large], p = 0.001) and CG (d = −0.77 [moderate], p = 0.049). No training type influenced CMJ performance. Smaller area size elicited contrasting results in terms of metabolic demand compared with larger sizes (i.e., lower HRmean but higher [La] and CR-10), whereas free combat induced variables' consistently higher values compared with imposed 1:2 ratio (Study 1). Taekwondo training is effective to improve VO2max and agility (Study 2), but small combat training modality should be investigated further.

Comparison of Two Tests to Determine the Maximal Aerobic Speed

2020 ◽  
Vol 60 (2) ◽  
pp. 252-262
Author(s):  
Benhammou Saddek ◽  
Jérémy B.J. Coquart ◽  
Laurent Mourot ◽  
Belkadi Adel ◽  
Mokkedes Moulay Idriss ◽  
...  
Keyword(s):  
Physiological Responses ◽  
Intraclass Correlation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Random Order ◽  
Standard Test ◽  
Maximal Heart Rate ◽  
Distance Runners ◽  
Gold Standard Test ◽  
Maximal Aerobic Speed

SummaryThe aims of this study were (a): to compare maximal physiological responses (maximal heart rate: HRmax and blood lactate concentration: [La-]) and maximal aerobic speed (MAS) achieved during a gold standard test (T-VAM) to those during a new test entitled: the 150-50 Intermittent Test (150-50IT), and (b): to test the reliability of the 150-50IT. Eighteen middle-distance runners performed, in a random order, the T-VAM and the 150-50IT. Moreover, the runners performed a second 150-50IT (retest). The results of this study showed that the MAS obtained during 150-50IT were significantly higher than the MAS during the T-VAM (19.1 ± 0.9 vs. 17.9 ± 0.9 km.h−1, p < 0.001). There was also significant higher values in HRmax (193 ± 4 vs. 191 ± 2 bpm, p = 0.011), [La-] (11.4 ± 0.4 vs. 11.0 ± 0.5 mmol.L−1, p = 0.039) during the 150-50IT. Nevertheless, significant correlations were noted for MAS (r = 0.71, p = 0.001) and HRmax (r = 0.63, p = 0.007). MAS obtained during the first 150-50IT and the retest were not significantly different (p = 0.76) and were significantly correlated (r = 0.94, p < 0.001, intraclass correlation coefficient = 0.93 and coefficient of variation = 6.8 %). In conclusion, the 150-50IT is highly reproducible, but the maximal physiological responses derived from both tests cannot be interchangeable in the design of training programs.

scholarly journals Gender Differences in Postural Stability among 13-Year-Old Alpine Skiers

2020 ◽  
Vol 17 (11) ◽  
pp. 3859 ◽  
Author(s):  
Agnieszka D. Jastrzębska
Keyword(s):  
Gender Differences ◽  
Postural Balance ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Body Sway ◽  
Foot Pressure ◽  
Eyes Closed ◽  
Before And After ◽  
Eyes Open ◽  
Alpine Skiers

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.

scholarly journals Response to Three Weeks of Sprint Interval Training Cannot Be Explained by the Exertional Level

Medicina ◽  
2020 ◽  
Vol 56 (8) ◽  
pp. 395
Author(s):  
Raulas Krusnauskas ◽  
Nerijus Eimantas ◽  
Neringa Baranauskiene ◽  
Tomas Venckunas ◽  
Audrius Snieckus ◽  
...  
Keyword(s):  
Average Power ◽  
Lactate Concentration ◽  
Training Session ◽  
Blood Lactate Concentration ◽  
Interval Training ◽  
Knee Extension ◽  
Peak Oxygen Uptake ◽  
Sprint Interval Training ◽  
Low Responders ◽  
Before And After

Background and Objectives: The all-out mode of sprint interval training (SIT) has been shown to be an efficient method for improving sports performance, exercise capacity, and aerobic fitness. Although the benefits of SIT are well described, the mechanisms underlying the different degrees of response remain largely unexplored. We aimed to assess the effects of exertion on the responsiveness to SIT. Materials and Methods: The participants were 28 young untrained men (mean ± SD age 25.7 ± 6.03 years) who exhibited either a large or small increase in Wingate test average power in response to nine SIT sessions performed over three weeks. Each training session comprised four–six bouts of 30 s all-out cycling interspaced with 4 min of rest. Individual responses were assessed using heart rate (HR) during exercise for all nine sessions, as well as blood lactate concentration up to 1 h, and the decrement in maximal voluntary knee extension torque (MVC) up to 24 h after the first and last training sessions. Peak oxygen uptake (VO2peak) and maximum HR were measured before and after training during an incremental cycling test to exhaustion. Results: Although all participants showed benefits of SIT such as increased VO2peak, the increase in anaerobic cycling power varied between participants. We identified 17 high responders and nine low responders, whose average power outputs were 0.80 ± 0.22 and 0.22 ± 0.19 W/kg, respectively. The HR achieved during any of the training sessions did not differ between high and low responders. The lactate kinetics did not differ between groups before and after the intervention. Training resulted in a more rapid recovery of MVC without any discernible differences between the high and low responders. Conclusion: The differences in the responses to SIT are not dependent on the exertion level during training.

scholarly journals Modulation of Endothelial Glycocalyx and Microcirculation in Healthy Young Men during High-Intensity Sprint Interval Cycling-Exercise by Supplementation with Pomegranate Extract. A Randomized Controlled Trial

2020 ◽  
Vol 17 (12) ◽  
pp. 4405
Author(s):  
Zivile Pranskuniene ◽  
Egle Belousoviene ◽  
Neringa Baranauskiene ◽  
Nerijus Eimantas ◽  
Egle Vaitkaitiene ◽  
...  
Keyword(s):  
High Intensity ◽  
Controlled Trial ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Endothelial Glycocalyx ◽  
Control Group ◽  
Cycling Exercise ◽  
Before And After ◽  
Interval Cycling ◽  
Experimental Group

The natural components of the pomegranate fruit may provide additional benefits for endothelial function and microcirculation. It was hypothesized that supplementation with pomegranate extract might improve glycocalyx properties and microcirculation during acute high-intensity sprint interval cycling exercise. Eighteen healthy and recreationally active male volunteers 22–28 years of age were recruited randomly to the experimental and control groups. The experimental group was supplemented with pomegranate extract 20 mL (720 mg phenolic compounds) for two weeks. At the beginning and end of the study, the participants completed a high-intensity sprint interval cycling-exercise protocol. The microcirculation flow and density parameters, glycocalyx markers, systemic hemodynamics, lactate, and glucose concentration were evaluated before and after the initial and repeated (after 2 weeks supplementation) exercise bouts. There were no significant differences in the microcirculation or glycocalyx over the course of the study (p < 0.05). The lactate concentration was significantly higher in both groups after the initial and repeated exercise bouts, and were significantly higher in the experimental group compared to the control group after the repeated bout: 13.2 (11.9–14.8) vs. 10.3 (9.3–12.7) mmol/L, p = 0.017. Two weeks of supplementation with pomegranate extract does not influence changes in the microcirculation and glycocalyx during acute high-intensity sprint interval cycling-exercise. Although an unexplained rise in blood lactate concentration was observed.

Blood Lactate Levels in Free-Swimming Rainbow Trout (Salmo gairdneri) Before and After Strenuous Exercise Resulting in Fatigue

1976 ◽  
Vol 33 (1) ◽  
pp. 173-176 ◽  
Author(s):  
William R. Driedzic ◽  
Joe W. Kiceniuk
Keyword(s):  
Rainbow Trout ◽  
Blood Lactate ◽  
White Muscle ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Strenuous Exercise ◽  
Salmo Gairdneri ◽  
Before And After ◽  
Lactate Levels

Rainbow trout (Salmo gairdneri) were exercised to fatigue in a series of 60-min stepwise increasing velocity increments. There was no increase in blood lactate concentration, serially sampled during swimming by means of indwelling dorsal and ventral aortic catheters, at velocities as high as 93% of critical velocity of individuals. The data show that under these conditions the rate of production of lactate by white muscle, at less than critical velocities, is minimal or that the rate of elimination of lactate from white muscle is equal to its rate of utilization elsewhere. Immediately following fatigue blood lactate level increases rapidly. During the recovery period there appears to be a net uptake of lactate by the gills.

Mechanical and electromyographic analysis of reciprocal inhibition at the human ankle joint

1995 ◽  
Vol 74 (2) ◽  
pp. 849-855 ◽  
Author(s):  
T. Sinkjaer ◽  
J. Nielsen ◽  
E. Toft
Keyword(s):  
Ankle Joint ◽  
Stretch Reflex ◽  
Plantar Flexion ◽  
Joint Stiffness ◽  
Common Peroneal Nerve ◽  
Reciprocal Inhibition ◽  
Mechanical Effect ◽  
Voluntary Contraction ◽  
Plantar Flexors ◽  
Before And After

1. The purpose of the present study is to investigate how reciprocal inhibition influences the mechanical and electromyographic (EMG) properties of the ankle plantar flexors in humans during a voluntary contraction. 2. At different levels of maintained plantar flexion contractions ranging from 0 to 20 Nm, the size of the soleus EMG stretch reflex and the ankle joint stiffness (ration between the torque increment and the amplitude of the stretch) were measured in response to an imposed dorsiflexion. At matched plantar flexion contraction levels, stretch responses were compared before and after reversible block of the common peroneal nerve (CPN). Stretch responses were also measured during an attempted voluntary fictive dorsiflexion after CPN block. 3. In the preactivated soleus muscles, the phasic EMG response to stretch consisted of two peaks labeled M1 and M2. After CPN block, the M1 short-latency stretch reflex on average increased by 25 +/- 5.7%, mean +/- SD (P < 0.001), and the M2 stretch reflex increased on average by 29 +/- 13.0% (P = 0.002). 4. The total stiffness of the ankle joint during a stretch is the sum of the nonreflex and the reflex mediated stiffness. The total stiffness after CPN block increased on average by 13 +/- 2.7% (P = 0.002) and the estimated reflex stiffness by 33 +/- 6.5% (P < 0.001). 5. When the subjects were asked to make a strong dorsiflexion after CPN block, the soleus stretch reflex was depressed to the extent that the reflex mediated mechanical effect around the ankle joint was abolished.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar gas composition and exchange during deep breath-hold diving and dry breath holds in elite divers

1991 ◽  
Vol 70 (2) ◽  
pp. 794-802 ◽  
Author(s):  
G. Ferretti ◽  
M. Costa ◽  
M. Ferrigno ◽  
B. Grassi ◽  
C. Marconi ◽  
...  
Keyword(s):  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Breath Hold ◽  
O2 Consumption ◽  
Gas Composition ◽  
Arterial Blood ◽  
Co2 Output ◽  
Before And After ◽  
Volume Blood ◽  
End Tidal

End tidal O2 and CO2 (PETCO2) pressures, expired volume, blood lactate concentration ([Lab]), and arterial blood O2 saturation [dry breath holds (BHs) only] were assessed in three elite breath-hold divers (ED) before and after deep dives and BH and in nine control subjects (C; BH only). After the dives (depth 40-70 m, duration 88-151 s), end-tidal O2 pressure decreased from approximately 140 Torr to a minimum of 30.6 Torr, PETCO2 increased from approximately 25 Torr to a maximum of 47.0 Torr, and expired volume (BTPS) ranged from 1.32 to 2.86 liters. Pulmonary O2 exchange was 455-1,006 ml. CO2 output approached zero. [Lab] increased from approximately 1.2 mM to at most 6.46 mM. Estimated power output during dives was 513-929 ml O2/min, i.e. approximately 20-30% of maximal O2 consumption. During BH, alveolar PO2 decreased from approximately 130 to less than 30 Torr in ED and from 125 to 45 Torr in C. PETCO2 increased from approximately 30 to approximately 50 Torr in both ED and C. Contrary to C, pulmonary O2 exchange in ED was less than resting O2 consumption, whereas CO2 output approached zero in both groups. [Lab] was unchanged. Arterial blood O2 saturation decreased more in ED than in C. ED are characterized by increased anaerobic metabolism likely due to the existence of a diving reflex.

Repeated-Sprint Training in Hypoxia Induced by Voluntary Hypoventilation in Swimming

2017 ◽  
Vol 12 (3) ◽  
pp. 329-335 ◽  
Author(s):  
Laurent Trincat ◽  
Xavier Woorons ◽  
Grégoire P. Millet
Keyword(s):  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Sprint Training ◽  
Training Performance ◽  
Repeated Sprint ◽  
Normal Breathing ◽  
Innovative Method ◽  
Before And After ◽  
Voluntary Hypoventilation ◽  
Competitive Swimmers

Purpose:Repeated-sprint training in hypoxia (RSH) has been shown as an efficient method for improving repeated-sprint ability (RSA) in team-sport players but has not been investigated in swimming. We assessed whether RSH with arterial desaturation induced by voluntary hypoventilation at low lung volume (VHL) could improve RSA to a greater extent than the same training performed under normal breathing (NB) conditions.Methods:Sixteen competitive swimmers completed 6 sessions of repeated sprints (2 sets of 16 × 15 m with 30 s send-off) either with VHL (RSH-VHL, n = 8) or with NB (RSN, n = 8). Before and after training, performance was evaluated through an RSA test (25-m all-out sprints with 35 s send-off) until exhaustion.Results:From before to after training, the number of sprints was significantly increased in RSH-VHL (7.1 ± 2.1 vs 9.6 ± 2.5; P < .01) but not in RSN (8.0 ± 3.1 vs 8.7 ± 3.7; P = .38). Maximal blood lactate concentration ([La]max) was higher after than before in RSH-VHL (11.5 ± 3.9 vs 7.9 ± 3.7 mmol/L; P = .04) but was unchanged in RSN (10.2 ± 2.0 vs 9.0 ± 3.5 mmol/L; P = .34). There was a strong correlation between the increases in the number of sprints and in [La]max in RSH-VHL only (R = .93, P < .01).Conclusions:RSH-VHL improved RSA in swimming, probably through enhanced anaerobic glycolysis. This innovative method allows inducing benefits normally associated with hypoxia during swim training in normoxia.

Achilles Tendon Mechanical Properties After Both Prolonged Continuous Running and Prolonged Intermittent Shuttle Running in Cricket Batting

2013 ◽  
Vol 29 (4) ◽  
pp. 453-462 ◽  
Author(s):  
Laurence Houghton ◽  
Brian Dawson ◽  
Jonas Rubenson
Keyword(s):  
Achilles Tendon ◽  
Elastic Energy ◽  
Plantar Flexion ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Force Transmission ◽  
Before And After ◽  
Tendon Force ◽  
Force Displacement ◽  
Tendon Properties

Effects of prolonged running on Achilles tendon properties were assessed after a 60 min treadmill run and 140 min intermittent shuttle running (simulated cricket batting innings). Before and after exercise, 11 participants performed ramp-up plantar flexions to maximum-voluntary-contraction before gradual relaxation. Muscle-tendon-junction displacement was measured with ultrasonography. Tendon force was estimated using dynamometry and a musculoskeletal model. Gradients of the ramp-up force-displacement curves fitted between 0–40% and 50–90% of the preexercise maximal force determined stiffness in the low- and high-force-range, respectively. Hysteresis was determined using the ramp-up and relaxation force-displacement curves and elastic energy storage from the area under the ramp-up curve. In simulated batting, correlations between tendon properties and shuttle times were also assessed. After both protocols, Achilles tendon force decreased (4% to 5%,P< .050), but there were no changes in stiffness, hysteresis, or elastic energy. In simulated batting, Achilles tendon force and stiffness were both correlated to mean turn and mean sprint times (r= −0.719 to −0.830,P< .050). Neither protocol resulted in fatigue-related changes in tendon properties, but higher tendon stiffness and plantar flexion force were related to faster turn and sprint times, possibly by improving force transmission and control of movement when decelerating and accelerating.

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