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Discussion Both aerobic fitness and anaerobic capacity were improved by HIT training, but these changes cannot be predicted by the changes in the training performance. References Gibala MJ, Little JP, Macdonald MJ, Hawley JA. (2012). J Physiol, 590(Pt 5):1077-1084
EXHAUSTIVE CYCLING EXERCISE TERMINATES EARLIER FOLLOWING PRIOR UPPER BODY EXERCISE DESPITE LESS
QUADRICEPS MUSCLE FATIGUEJohnson, M., Williams, N., Hannah, R.
Nottingham Trent University Changes in the metabolic milieu of locomotor muscles during heavy exercise may elicit inhibitory feedback to the central nervous system, thereby influencing the magnitude of central motor drive to prevent the degree of peripheral muscle fatigue and/or sensory perception exceeding a “critical” individual level . Whether exhaustive exercise terminates due to reaching a critical level of peripheral fatigue per se or an intolerable level of sensory perception remains unknown. Therefore, we aimed to differentiate these influences by examining the effects of a pre-existing metabolite accumulation, achieved using prior upper body exercise, on cycling exercise capacity, effort perception, and locomotor muscle fatigue. Eight males performed 3 constant power cycling tests at 85% Wmax (mean (SD): 272 (26) W). Cycling was performed to exhaustion without (C) or with (AC) prior arm-cranking exercise (8 x 1 min bouts, interspersed by 30 s rest intervals, at an intensity of 1.0-1.5W/kg body mass), or without prior exercise and for an equal duration to that achieved during AC (ISO). Arm-cranking was followed by a 6 min rest period prior to cycling. Blood lactate concentration ([La]) was measured before (PRE-CYC) and after (POSTCYC) cycling. Rating of perceived exertion (RPE) for leg discomfort was measured following 3 min of cycling and POST-CYC. Peripheral muscle fatigue was assessed via changes in potentiated (using maximal voluntary contractions) quadriceps twitch force (QTF) obtained via electrical stimulation of the femoral nerve. Cycling time to exhaustion during AC and ISO (4.33 (1.10) min) was 38% shorter than during C (7.46 (2.79) min) (P0.01). PRE-CYC [La] was higher during AC (9.3 (1.9) mmol/L) compared to C and ISO (pooled mean: 0.7 (0.3) mmol/L) (P0.01), whereas POST-CYC [La] differed between all trials (C: 11.5 (3.0) mmol/L; AC: 13.9 (2.4) mmol/L; ISO: 9.2 (2.6) mmol/L) (P0.05).
Following 3 min of cycling RPE during C (3.6 (1.3)) and ISO (3.7 (1.4)) were similar, whereas both were lower compared to AC (6.0 (1.5)) (P0.05). POST-CYC RPE during C (7.9 (2.0)) and AC (8.6 (1.7)) were similar, whereas both were higher compared to ISO (4.6 (1.8)) (P0.01).
QTF was unchanged after arm-cranking. The decrease in QTF following C (-38%) was greater than the similar decreases observed after AC (-26%) (P0.01) and ISO (-24%) (P0.05). In summary, compared to C the voluntary termination of exhaustive cycling during AC was associated with less quadriceps muscle fatigue but the same level of RPE. We thus attribute the reduced exercise capacity during AC to the attainment of a critical level of sensory perception resulting from metabolite accumulation, rather than a critical level of quadriceps muscle fatigue per se.  Amann M (2011). Med Sci Sports Exerc, 43, 2039-45
EFFECTS OF TWO CYCLING LEG EXERCISES ON MAXIMAL POWER: COMPARISON BETWEEN THE WINGATE AND THE
FORCE-VELOCITY TESTSJaafar, H., Rouis, M., Attiogbe, E., Vandewalle, H., Driss, T.
Université Paris Ouest Nanterre La défense Introduction Maximal power output on cycle ergometer depends on both pedaling velocity and braking force. It can be estimated from the force-velocity relationship (Pmax, Vandewalle et al., 1987) or by measuring the highest mechanical power (Ppeak) produced during an all-out Wingate test (Bar-Or, 1987). However, in order to be valid indicator of anaerobic fitness, the testing protocol must consider the resistance at which force is produces to achieve a maximal power output. Thus, the aim of this study was to compare maximal power measured by the force-velocity test (FVT) and by the Wingate test (WT) performed with two different loads among two groups with different anaerobic fitness. Methods Two groups of healthy males according to their individual training histories and physical fitness participated in this study. They consisted of ten active subjects (AS, 22.7 ± 1.4 years, 78.9 ± 6.6 kg and 1.85 ± 0.05 m) and ten recreational subjects (RS,
22.9 ± 1.7 years, 73.3 ± 10.4 kg and 1.81 ± 0.06 m). After a familiarization session, they performed randomly on three separate occasions a FVT according to the protocol proposed by Vandewalle et al. (1987) and two WTs with different loads, 8.7% (WT8.7%) according to the table optimization of Bar-Or (1987) and 11% (WT11%) of body mass (BM) on Monark cycle ergometer. Data were analyzed by ANOVA (group × test) with repeated measures. Results Pmax values (W.BM-1) obtained from FVT were 15.60 ± 1.45 and 12.05 ± 0.55 W.kg-1, respectively for AS and RS. Ppeak values (W.BM-1) measured during the WT11% were 14.95 ± 1.09 and 11.98 ± 0.72 W.kg-1, respectively for AS and RS, and during the WT8.7% were 13.58 ± 0.96 and 11.40 ± 0.70, respectively for AS and RS. Significant main effects of group, test and group by test interaction were found (p 0.001). Discussion In both groups, Ppeak measured during WT8.7% was significantly lower than Ppeak WT11% and Pmax. Consequently, a braking force 8.7% of BM underestimates maximal power and is not an optimal load, even in subjects with a low anaerobic level. In RS, Ppeak WT11% and Pmax were almost equal due to the similarity of the force and velocity values corresponding to maximal power in the FVT and WT. However, Pmax in AS was significantly higher than Ppeak WT11%, which corresponded to an underestimation of maximal power in WT using 11% of BM. Indeed, maximal power is occurred at optimal velocity and braking force (Hintzy et al., 1999; Vandewalle et al., 1985). Consequently, the load optimization should take into account not only age, individual body build, and composition, but anaerobic fitness as well. Our study suggested that FVT results in more sensible and individualized test for assessment of maximal mechanical power. References Bar-Or O (1987). Sports Med, 4(6), 381-394. Hintzy F, Belli A, Grappe F, Rouillon JD (1999). Eur J Appl Physiol, 79(5), 426-432. Vandewalle H, Pérès G, Heller J, Monod H (1985). Eur J Appl Physiol, 54(2), 222-229. Vandewalle H, Peres G, Heller J, Panel J, Monod H (1987). Eur J Appl Physiol, 56, 650-656.
DOES MAXIMAL POWER OUTPUT ON A CYCLE ERGOMETRE DEPEND ON RATE OF FORCE DEVELOPMENT AND
MUSCULO-TENDINOUS STIFFNESS OF THE PLANTAR ANKLE FLEXOR MUSCLES?Majdi, R., Lambertz, D., Jaafar, H., Vandewalle, H., Driss, T.
Université Paris Ouest Nanterre La Défense Introduction The rate of force development depends on muscle fibre type. Furthermore, several studies suggested differences in the elastic behaviour of fast and slow muscles and were in favour of a negative relationship between stiffness and the percentage of fast fibres. Some results in single fibres or isolated muscles and in humans suggest that stiffness could be higher in the subjects with high percentage of slow fibres, i.e. the less powerful subjects. In this case, Pmax would be negatively correlated with musculo-tendinous stiffness while being positively correlated with MRTD. The aim of the present study was to verify if high MRTD and high indices of stiffness of the series elastic component of the plantar flexors were obtained in the most powerful subjects. Methods Twenty-one male physical education students (79.8 ± 9.7 kg, 1.83 ± 0.08 m) participated in this study. Maximal power on a cycle ergometre (Pmax BM-1) was computed from the results of the force-velocity tests according to the protocol proposed by Vandewalle et al. (1985). The torque during a maximal voluntary contraction (TMVC) and musculo-tendinous stiffness (MTS) of the plantar flexors were studied by means of an ankle ergometre and quick release method (Lambertz et al. 2001). During the same session, maximal rate of torque development (MRTD) was measured according to the protocol of Sahaly et al. (2001). MTS was determined at 20, 40, 60 and 80% TMVC (S0.2, S0.4, S0.6 and S0.8).
MTS was also predicted at 30% TMVC (S0.3) and 50% TMVC (S0.5) by interpolations of S0.2, S0.4 and S0.6. The relationship between Pmax, MRTD, TMVC and MTS has been tested by Pearson product-moment correlation (r), and linear regression analysis. The coefficient of determination (r2) was used to predict the proportion of the variance (fluctuation) of Pmax that is predictable from other variables (MRTD and MTS). Results Pmax BM-1 was significantly and positively correlated with MRTD related to body mass (r = 0.460; Pmax BM-1 = 11.2 + 0.62 MRTD BM-1, P 0.05) but the positive correlation between Pmax BM-1 and TMVC did not reach the significance level (P 0.05). Pmax BM-1 was significantly and positively correlated with the stiffness at S0.4 (Pmax BM-1 = 10.7 + 0.94 S0.4 BM-1) and S0.5 (0.44 ≤ r ≤ 0.45, P 0.05) but not with stiffness at S0.2, S0.6 and S0.8 (P 0.05). Discussion The results of the present study suggested that maximal power output during cycling is significantly correlated with the level of musculo-tendinous stiffness which corresponds to torque range around peak torque at optimal pedal rate. However, the low coefficient of determination (r2 = 0.203) between Pmax BM-1 and S0.4 BM-1 or S0.5 BM-1 suggested that Pmax BM-1 largely depended on other factors than the musculo-tendinous stiffness of the only plantar flexors. References Lambertz D, Pérot C, Kaspranski R, Goubel F (2001). J Appl Physiol, 90(1), 179-88. Sahaly R, Vandewalle H, Driss T, Monod H (2001). Eur J Appl Physiol, 85(3-4), 345-50. Vandewalle H, Pérès G, Heller J, Monod H (1985). Eur J Appl Physiol, 54(2), 222-9.
SPECIFICS OF MUSCLE ELECTRIC ACTIVITY DURING ARCHERY SHOOTINGBuchatskaya, I.N., Pukhov, A.M., Gorodnichev, R.M.
Velikiye Luki State Academy of Physical Education and Sports Introduction: The research goal was to study specifics of muscle electric activity when shooting arch. Methods: Eight highly-qualified archers underwent the study, each doing 10 shooting sessions of 3 shoots. Registering and analysis of shoot kynematic parametres was done with the help of the “Qualisys Track Manager” 3D video-analysing system (Sweden), electromyography - with the help of the 16channel ME6000 myograph and MEGAWIN software. Results: 12 “leading” muscles were determined out of 32 ones under study, the former had a high electromyographic amplitude and significant activity changes at various shoot stages. It became clear that on the group average (1st session, 46 %) the first to activate were the upper left dorsal fascicles of the trapezius muscle, those were also the first to stop contracting in the course of the shooting exercise. By the end of the exercise (10th session) the upper left dorsal fascicles of the trapezius muscle were the first to activate only in 31 % together with the upper right dorsal fascicles (31%), which attests to the fatigue process at the end of the shooting session. Electrical activity of the right extensor carpi ulnaris muscle and the left flexor carpi radialis muscle were at highest at the moment of the arrow release, which attests to a programmed control of the muscles at this particular stage. The EMG of the upper right dorsal and lower left dorsal fascicles of the trapezius muscle at the stage of “post-strengthen” showed sporadic high amplitude rises combining with low amplitude action potential, the latter fact speaks of the corrective-mechanism principle.
It was found out that out of all the shoots the “successful” ones amounted to 63% and, respectively, 37 % to the “unsuccessful”. A statistically valid direct dependence of the success was determined, based on the increase of average group amplitude values of the EMG of the following muscles – lower right dorsal fascicles of the trapezius muscle, posterior fascicles of the right deltoideus muscle, flexor carpi radialis muscle of the right hand, extensor carpi ulnaris muscle of the left hand. On the whole, the total electric activity of the mentioned muscles would increase by 28,6% compared with “unsuccessful” results. The latter fact attests to the dependence of the success on a higher electical amplitude of the muscles under study.
BLOOD LACTATE AFTER COMPETITIVE FREE DIVING AND SYNCHRONIZED SWIMMING EVENTSRodríguez-Zamora, L.1,2, Engan, H.K.2,3, Lodin-Sundström, A.2, Iglesias, X.1, Rodríguez, F.A.1, Schagatay, E.2,4 1: INEFC-Barcelona Sport Sciences Research Group, UB (Barcelona, Spain), 2: Department of Engineering and Sustainable Development, Mid Sweden University, Östersund, Sweden. 3: LHL Health Röros, The No Introduction Analysis of sports involving apnea is essential for the understanding of how dives with different levels of exertion and apneic durations lead to changes in the net lactate accumulation (NLA). The aim was to describe lactate accumulation during competition performances in different free-diving and synchronized swimming (SS) disciplines. Methods Volunteers were 43 free apnea divers and 34 synchronized swimmers competing at an elite level. Disciplines investigated were static apnea (STA), dynamic apnea with-(DYN) and without fins (DNF), deep diving disciplines constant weight with-(CWT) and without fins (CNF), and free immersion using upper body work (FIM). Competitive SS events included solo, duet and team routines. The blood lactate concentration (La) was measured at rest before (rLa), and 3 minutes after (La3post) dives and routines executed in competition. Results For the entire group of athletes the average rLa was
1.8±0.7mmol/L and La3post was 6.0±2.1mmol/L (p0.001). La3post was lower after STA (2.5±0.9mmol/L) than in all other disciplines (p0.05). It was also higher after CNF (7.6±1.8mmol/l) than after DYN (6.2±2.1), DNF (6.2±2.2), and all SS events (solo 6.3±2.0mmol/L, duet