ABSTRACT
The aim of this study was to investigate the effects of adding a high-intensity intermittent session twice a week during a 7-week karate training (KT) on markers of aerobic and anaerobic metabolisms in elite class karate athletes. Two groups were studied: a KT group (n=8, age 20.1+/-0.9 years, 70.0+/-8.8 kg) that followed traditional KT, and a group that followed combined traditional karate and a high-intensity intermittent training (HIT group, n=9, age 24.4+/-3.1 years, 67.0+/-7.8 kg). The subjects undertook a supramaximal exercise and a maximal oxygen uptake test before and after the training. Blood lactate, pH and plasma ammonia were determined at rest, immediately at the end of the supramaximal exercise and during the recovery period at 2, 4, 6, 8, 10 and 15 min. After the training period, no changes occurred in the KT group. However, in the HIT group, the time to exhaustion, MAOD and in the maximal oxygen uptake test were significantly improved by 23.6%, 10.3% and 4.6%, respectively. A clear-cut discrepancy was observed in the time course of lactate and pH in the supramaximal test after the training in the HIT group. We observed a significantly higher peak for lactate and a lower extreme value for pH with a shorter delay of appearance. At the end of the test, the lactate concentration increased significantly (+53.7%) and pH declined significantly, when compared with the values obtained after the same test before the training period. Ammonia was not influenced. The addition of high-intensity intermittent sessions twice per week during the period of KT induced beneficial physiological adaptations in athletes, allowing improvement in the duration of intense physical exercise before a state of fatigue is reached.
Subject(s)
Adaptation, Physiological/physiology , Exercise/physiology , Martial Arts/physiology , Physical Endurance/physiology , Adult , Ammonia/blood , France , Humans , Hydrogen-Ion Concentration , Lactic Acid/blood , Male , Oxygen Consumption/physiology , Young AdultABSTRACT
The purpose of this study was to compare maximal accumulated oxygen deficit (MAOD) and the time course of blood markers of the anaerobic metabolism in response to exhaustive supramaximal test in two elite (international vs. national) class karate athletes. Ten male international competitors from the French national team (Int, age 21.2 +/- 3.1 years, 71.9 +/- 11.4 kg) and eight national class (Nat, 23.7 +/- 2.4 years, 70.7 +/- 12.2 kg) athletes with a similar maximal oxygen uptake of 57.6 and 59.4 ml . kg (-1) . min (-1), respectively, were involved in this study. The MAOD was determined after an exhaustive supramaximal exercise (2 - 3 min at 140 % of their VO2max velocity) on a treadmill ergometer. Blood lactate, pH and plasma ammonia were determined at rest, immediately at the end of exercise and during the recovery period at 2, 4, 6, 8, 10 and 15 min. After the supramaximal exercise, a dramatic higher increase in the blood concentration of ammonia until its peak was observed in the Nat compared with the Int. Time course of [NH4+] and [La] reveals significant (p < 0.01) differences between the two groups. Peak values for [H+] (89.2 +/- 6.7 vs. 75.9 +/- 8.8 nmol . l (-1); p < 0.01), [NH4+] (180 +/- 67.9 vs. 118.7 +/- 22.7 micromol . l (-1); p < 0.05) and [La] (20.7 +/- 2.7 vs. 17.9 +/- 1.1 mmol.l (-1); p < 0.05) were higher in Nat compared with Int group, respectively. However, the MAOD was similar in both groups (67.8 +/- 8 ml . kg (-1) and 64.5 +/- 6.4 for Int and Nat groups, respectively). These data suggest that ammonia and lactate accumulation are sensitive to the level of performance in karate. Higher concentrations of these metabolites in blood after supramaximal exhaustive exercise may be related to either higher anaerobic contribution to energy supply in Nat or higher removal ability in the Int group.
Subject(s)
Ammonia/blood , Lactic Acid/blood , Martial Arts/physiology , Oxygen Consumption/physiology , Adult , Anaerobiosis , Analysis of Variance , Exercise Test , Humans , Hydrogen-Ion Concentration , Male , Statistics, NonparametricABSTRACT
This study aimed (i) to quantify the spontaneous coordination between breathing and hand rim wheelchair propulsion, (ii) to manipulate arm movement frequency and assess its effects on spontaneous coordination, and (iii) to investigate the hypothesis that entrainment of breathing improves economy of locomotion and leads to a lower rate of perceived exertion (RPE) compared with spontaneous breathing. Nine male, able-bodied participants completed four bouts of 6 min submaximal steady state exercise at 60 % of maximal propulsion velocity on a wheelchair ergometer, with spontaneous breathing and arm frequencies (Fspont), with 20 % higher and lower arm frequencies (F +20 and F -20, respectively) compared to Fspont accompanied with spontaneous breathing frequency, and by synchronising expiration phase with pushing time and inspiration phase with upper limb recovery time (C). Oxygen uptake and propulsion frequency were continuously recorded. The degree of coordination was expressed as a percentage of inspiration starting in the same phase of the wheelchair propulsion cycle (i.e. pushing and recovery times). No difference in degree of coordination was observed between Fspont, F -20 and F +20 conditions (49.2 +/- 12.1 %, 49.1 +/- 29.0 % and 48.2 +/- 29.4 %, respectively). Oxygen uptake increased significantly during C condition while RPE was significantly lower for C and F -20 (p < 0.05) compared to F +20 conditions. Contrary to what we expected, entrainment of breathing using a monofrequency ratio (C) induced a higher energy cost probably due to the mechanical properties of the wheelchair propulsion activity itself. In conclusion, this study showed that the same locomotor-respiratory coupling occurred during hand rim wheelchair propulsion regardless of the arm movement frequency, and that entrainment of breathing did not improve economy of locomotion.
Subject(s)
Arm/physiology , Hand/physiology , Locomotion , Movement/physiology , Respiration , Wheelchairs , Adult , Humans , Male , Task Performance and AnalysisABSTRACT
AIM: The aim of this study was to examine the ability of 5- to 7-year-old female (n=16) and male (n=16) children to use perceived exertion in order to self-regulate their running intensity. An estimation-production paradigm was used to determine if 1) self-regulation of exercise using OMNI Scale could be administered in young children, 2) children were able to distinguish 3 different intermittent exercise intensities and 3) gender would differentiate the use of perceived exertion. METHODS: Children underwent 1) 1 estimation trial and 2) 3 production trials. During the estimation trial, perceived exertion was estimated at the end of each stage of an incremental running field test. Then, during the production test, the children were requested to run in random order 300 m bouts on an outdoor track at an exercise intensity based on their interpretation of levels 2, 6 and 10 of the OMNI Scale. Heart rate was continuously recorded during both trials. RESULTS: Heart rate did not differ significantly between estimation and production trials at the level 2 (124.1 SD 6 vs 125.3 SD 4 bpm), 6 (164.9 SD 5 vs 166.2 SD 6 bpm) and 10 (200.9 SD 8 vs 203.1 SD 8) of the OMNI scale. Furthermore, HR responses at OMNI 6 were significantly (p<0.05) higher than OMNI 2, and OMNI 10 were significantly (p<0.05) higher that OMNI 6. No significant difference was found between female and male children. CONCLUSIONS: The present investigation supports the view that the young female and male children tested in this study were able to use perceived exertion to self-regulate during intermittent running exercises.
Subject(s)
Heart Rate/physiology , Physical Exertion/physiology , Running/physiology , Analysis of Variance , Child , Child, Preschool , Female , Humans , Male , Oxygen Consumption/physiologyABSTRACT
This study investigated the effects of 40-week training on anxiety and perceived fatigue in four elite triathletes. Anxiety and perceived fatigue were self-reported by the subjects twice a week by the way of a specific questionnaire and were linked by a mathematical model to the training loads calculated from the exercise heart rate. A significant relationship (r=0.32; p<0.001) between the training loads and anxiety was identified using a two-component model: a first, negative (i.e., anxiety decreased) short-term (tau (1)=23 days) function and a second, positive long-term (tau (2)=59 days) function. The relationship between the training loads and perceived fatigue was significant (r=0.30; p<0.001), with one negative function (tau (1)=4 days). This mathematical model can potentially describe the relationships between training loads and anxiety or perceived fatigue and may improve both the adjustment of the duration of tapering and the early detection of staleness.
Subject(s)
Anxiety/psychology , Fatigue/psychology , Models, Psychological , Sports/psychology , Workload/psychology , Adult , Competitive Behavior , Female , Humans , Male , Physical Education and Training/methods , Physical EnduranceABSTRACT
AIM: The aim of the study was to test the ability to estimate the power output (PO) and heart rate (HR) associated with ''anaerobic threshold'' levels for triathletes by means of a 30-min perceptive individual time trial (PITT30). METHODS: Thirteen triathletes (8 males and 5 females) performed an incremental exercise test to estimate maximal parameters such as oxygen uptake, power output and heart rate. From this incremental exercise test, the individual anaerobic threshold (IAT) and ventilatory threshold (VT) for all subjects were estimated. Then, the subjects completed a PITT30 at self-selected work intensity on a stationary ergometer equipped with the SRM Training System. Mean values of PO, HR, and pedalling cadence were recorded continuously between the 5th and the 30th min of the test. RESULTS: Significant correlations were observed between the mean PO recorded during PITT30 and PO measured at IAT (r=0.88; p<0.0001) and at VT (r=0.89; p<0.0001). Furthermore, bias and limits of agreement confirm the degree of association between the 3 METHODS: However, PITT30 over-estimated HR values compared to the values obtained at IAT and VT. CONCLUSION: It was concluded that, for triathletes, mean PO measured with PITT30 allows a partial valid estimation of PO associated with 2 known methods of ''anaerobic threshold'' determination. The application of PITT30 may offer a useful tool for athletes and coaches to estimate the ''anaerobic threshold'' in order to control accurately the training effects.
Subject(s)
Anaerobic Threshold/physiology , Bicycling/physiology , Exercise Test/psychology , Perception , Physical Endurance/physiology , Adult , Bicycling/psychology , Female , Humans , Male , Pulmonary Ventilation/physiology , Sports/physiology , Time , Time FactorsABSTRACT
Several indicators are used as indices of cardiorespiratory reserve. Among them, oxygen uptake (VO(2)) at peak and ventilatory threshold (VAT) levels are the most common used. In the present study, endurance training was used to evaluate and compare the usefulness of a new index, the Oxygen Uptake Efficiency Slope (OUES) as an alternative to the previous ones. Fifteen physical education student women participated in the study (8 as a trained group [T: age (mean +/- SD) 21.9 +/- 3.3 y, height 165.1 +/- 5.5 cm, weight 60.4 +/- 3.3 kg] and 7 as a control group [C: age 21.7 +/- 1.9 y, height 165.4 +/- 7.2 cm, weight 59.6 +/- 8.6 kg]). Before and after 6 weeks of the Square-Wave Endurance Exercise Test (SWEET) training program or daily activities, they performed an incremental test (30 W/3 min) on a cycle ergometer to determined VO(2), power output and parameters associated with breathing efficiency (the respiratory equivalents, and the ventilatory dead space to tidal volume ratio [Vd/Vt]) at peak- and VAT-levels. The slope of the relationship between ventilation and carbon dioxide production was also calculated. OUES, derived from the logarithmic relationship between VO(2) and minute ventilation (V(E)), was determined at 75 % (OUES75), 90 % (OUES90) and 100 % (OUES100) of exercise duration. After endurance training in T, VO(2) and power output were significantly improved at peak- and VAT-levels while all breathing efficiency indices remained unchanged. No changes were observed in C after 6 weeks. Despite significant correlation between OUES values and VO(2) at peak- and VAT-levels, OUES75, OUES90 and OUES100 did not significantly change after endurance training. While VO(2) and power output at peak- and VAT-levels increased in all T, training-induced changes in OUES appeared more variable. We concluded that OUES was not sufficiently sensitive to highlight improvement of cardiorespiratory reserve after endurance training whereas VO(2) at peak and VAT levels did.
Subject(s)
Exercise/physiology , Oxygen Consumption/physiology , Physical Endurance/physiology , Physical Fitness , Adult , Female , Humans , Physical Education and Training , Time FactorsABSTRACT
AIM: The rules of gymnastics impose an element of static strength such as an iron cross (IC) on the rings. For IC training, coaches use a custom made device -- the herdos -- to simulate the conditions of competition. The purpose was to compare muscle activity and coordination during IC performed both on the rings and using herdos. Secondly, we tried to determine whether herdos usage induced functional adaptations of the shoulder muscles. METHODS: Six male gymnasts performed 10 IC in each condition. Surface electromyogram of muscles pectoralis major, latissimus dorsi, teres major, infraspinatus, rhomboideus, trapezius, serratus anterior, biceps brachii, and triceps brachii in the right shoulder were analysed using root-mean-square (RMS), and muscle part's in each condition. Muscle part represents the contribution of each of the 9 shoulder muscles studied in each condition. Total muscle activity (SUM) was also used to compare the 2 conditions. RESULTS: Except for the muscle teres major, the RMS decreases (p<0.05) when using the herdos. The SUM also decreases (p<0.05) when using this device. The muscle parts indicate that the contribution of the muscle latissimus dorsi decreases (p<0.05) when using the herdos. These results suggest that the herdos modified shoulder coordination. But their usage does not seem to induce any functional adaptations of these muscles. CONCLUSIONS: The herdos do not seem to provide a valid method to reproduce the same shoulder coordination as on the rings. Therefore IC training with this special device could be called in question.
Subject(s)
Gymnastics/physiology , Muscle, Skeletal/physiology , Shoulder/physiology , Adult , Electromyography , Humans , MaleABSTRACT
AIM: The aim of this study was to analyze the links between tests performances (vertical jump and force-velocity sprint on cycle ergometer) and 2 different karate level groups in order to propose a test battery adjusted to karate. METHODS: Twenty-two karate competitors (10 national junior team (IJ) and 12 national competition level (NL)) performed 4 maximal squat jumps (SJ), 4 maximal counter movement jumps (CMJ) on an ergojump and 3 8-s sprints on a friction braked cycle ergometer (friction loads of 0.5, 0.7, 0.9 N x kg(-1)). The maximal theoretical force (F(0)) and velocity (V(0)), the maximal power output (P(max)) and the optimal pedalling velocity (V(opt)) were derived from both the force -- velocity and the power -- velocity relationships plotted from all the 3 friction loads data. V(0), F(0), V(opt), P(max) and the best SJ and CMJ, were compared between IJ and NL groups. RESULTS: The IJ group was characterised by significantly higher values of V(0) (+13%) and SJ (+14.3%) compared to NL group, whereas no significant difference was observed between groups for F(0). Thus, karate performance would depend on maximal velocity and explosive strength. In addition, V(opt) was significantly higher in IJ group compared to NL group (135.4 rpm vs 119.2 rpm, p<0.001). Although based upon indirect evidence, these results accounted for mechanical functional capabilities of experts which could be particularly valuable when monitoring training of karate competitor. CONCLUSIONS: A force-velocity and a vertical jump tests may be applied in the functional assessment of karate competitor.
Subject(s)
Acceleration , Exercise Test , Martial Arts/physiology , Motor Activity/physiology , Muscle Contraction/physiology , Muscle, Skeletal/physiology , Adult , Ergometry , Humans , MaleABSTRACT
STUDY DESIGN: Before and after investigation of the effects of a wheelchair ergometer Training programme. OBJECTIVE: To investigate the effects of an original interval-training programme on work capacity and cardiorespiratory variables with spinal cord-injured persons (SCIP's) on a wheelchair-specific ergometer. SETTING: BESANCON, FRANCE. METHODS: Seven SCIP's (male) performed 45 min of wheelchair ergometry three times per week, for 6 weeks. Training effects on maximal dynamic performance and endurance capacity were studied by comparison of performance and cardiorespiratory responses observed during both a maximal progressive test (10 W/2 min) and the same training session performed before and after training. RESULTS: Training induced significant improvements in maximal tolerated power (+19.6%), in peak oxygen consumption (VO2,+16%), and in oxygen pulse (O2p,+18.7%). At ventilatory threshold, significant improvements were also observed in power output (+63%), VO2VT(+ 34.1), ventilation VEVT(+ 37.1%), and V2pVT(+ 19.9% ). Heart rate and ventilation were significantly lower (-11 and -14.6%, respectively) after training at the same work rate, while VO2 was unchanged. Between the first and the last training session, the total physical work was improved by 24.7%, whereas heart rate was unchanged. CONCLUSION: An interval-training programme individualised to each paraplegic subject using a wheelchair ergometer can significantly improve the fitness level and endurance capacity.
Subject(s)
Ergometry/methods , Exercise/physiology , Spinal Cord Injuries/rehabilitation , Wheelchairs , Adult , Ergometry/instrumentation , Exercise Test/instrumentation , Exercise Test/methods , Humans , Lumbar Vertebrae/injuries , Male , Middle Aged , Spinal Cord Injuries/physiopathology , Thoracic Vertebrae/injuriesABSTRACT
The aim of this study was to investigate the metabolic and physiological responses to a laboratory-based simulated 30-min individual time-trial (ITT 30 ) in cycling at a self-selected intensity. Twelve experienced triathletes (n = 4 women) performed a progressive incremental exercise test on a cycle ergometer to determine .VO2max (52 +/- 5 ml x min -1 x kg -1), maximum power output (300 +/- 12 W), and the second ventilatory threshold. Then, the subjects completed an ITT30 at self-selected work intensity on a stationary ergometer equipped with the SRM Training System. In all subjects, during the ITT30, heart rate and minute ventilation increased (p < 0.05) progressively whereas oxygen consumption and power output remained unchanged. Triathletes rode at consistent pacing corresponding to their highest steady state of blood lactate concentration that increased by no more than 1.0 mmol x l -1 during the final 20-min of ITT30. The self-selected intensity of triathletes during ITT30 represented 88 +/- 5 % (mean +/- SD) of .VO2max and was not significantly different to the energy demand corresponding to the second ventilatory threshold (84 +/- 5 % of .VO2max). Our data suggest that ITT 30 at a self-selected intensity is a good predictor of individual endurance capacity and may be used to estimate racing pace for training purposes. This performance test for the identification of the exercise intensity that demarcate "steady state" is less troublesome than some of the traditional methods, limiting testing to a single session.
Subject(s)
Bicycling/physiology , Adult , Energy Metabolism , Exercise Test , Female , Humans , Lactic Acid/blood , Male , Oxygen Consumption , Pulmonary Gas Exchange , RespirationABSTRACT
BACKGROUND: This investigation sought to characterise the oxygen uptake (VO2) off-transient kinetics from severe exercise and to clarify discrepancies between on- and off-transient kinetics for VO2 seen in humans. METHODS: Eleven competitive endurance athletes underwent treadmill running until exhaustion at work-rates corresponding to the speed that elicited approximately 95% of maximal VO2. Gas exchange variables were determined breath-by-breath. Computerised non-linear regression techniques were used to fit the VO2 on- and off-transient kinetics. A 3-exponential model described the VO2 on-transient. VO2 off-transient was analysed to each response time course using 3 different models: a single-exponential model for the entire period and 2 3-exponential models where exponential terms starting either together after a common time delay or after independent time delays. RESULTS: Both 3-exponential models provided an excellent fit (r2>0.90) to the off-transient data. Compared with on-transient, VO2 off-transient kinetics was associated with a slower primary phase (time constant: 16+/-4 vs 39+/-13 sec, p<0.01) but was similar both in time delay and amplitude. CONCLUSIONS: These data indicate that there is no general symmetry between the exercise and recovery kinetics for VO2 because the response of the primary phase of VO2 off-transient resolves to a greater time constant, reflecting altered tissue metabolism. However, the mechanism(s) for the slow component is slow both in developing and to recover within the severe exercise domain.
Subject(s)
Exercise Tolerance/physiology , Exercise/physiology , Oxygen Consumption/physiology , Running/physiology , Adult , Exercise Test/methods , Humans , Kinetics , Nonlinear Dynamics , Physical Exertion/physiology , Pulmonary Gas Exchange/physiologyABSTRACT
OBJECTIVES: The purpose of this study was to compare the effects of a rehabilitation program on the perceived exertion (PE) and the cardioventilatory responses during exercise in healthy people and paraplegics. METHODS: A group of seven healthy persons (age 26.6 SD 6.2 years) and one of seven paraplegics (age 42 SD 15.9 years) participated in a rehabilitation program composed of Square Wave Exercise Tests (SWEET) during six weeks. The maximal oxygen uptake, the power output (PO), heart rate (HR) and measures of PE using the Borg CR 10 scale were investigated during a maximal graded test performed before and after the rehabilitation program. During the first SWEET session (SWEET 1) measures of PE and HR (base and peak) were also investigated and compared to the last session (SWEET 2) of the same absolute workload after the 6 weeks. RESULTS: Statistical analysis revealed no significant difference in both groups for PE between the two maximal graded tests. However, a significant decrease in the PE values (P<0.01) was observed in both groups during the SWEET 2. There was no significant difference in maximal HR between the two graded tests, but a significant decrease in HR (P<0.0001 for base HR and P<0.001 for peak HR) was observed in SWEET 2 compared to 1. The maximal tolerated power (MTP) and the peak oxygen uptake increased significantly in both healthy and paraplegic groups (P<0.0001 and P<0.05 respectively) after the 6 weeks of rehabilitation exercise. CONCLUSION: The results of the present study suggest that PE could be used to control the exercise intensity during a rehabilitation training program for paraplegics, similar to healthy subjects. The increase in the peak oxygen uptake and MTP demonstrates the positive effects of the rehabilitation program on the physical fitness of the subjects.
Subject(s)
Paraplegia/rehabilitation , Physical Exertion , Spinal Cord Injuries/rehabilitation , Wheelchairs , Adult , Ergometry/methods , Exercise Test/methods , Exercise Therapy , Factor Analysis, Statistical , Heart Rate , Humans , Male , Middle Aged , Oxygen Consumption , Spinal Cord Injuries/psychologyABSTRACT
The purpose of the present study was to examine oxygen consumption (VO(2) ) kinetics during severe-intensity running exercise through a four-phase model that considered a decrease in VO(2) at the end of the exercise in light of previous research in which this decrease was only noticed. After determination of maximal oxygen consumption VO(2) max), thirteen highly trained males performed a square-wave running to exhaustion at approximately 95 % of VO(2) max on a level treadmill. VO(2) and ventilatory gas exchange variables were determined breath-by-breath. Computerised non-linear regression techniques incorporating exponential and linear terms were used to describe VO(2) and ventilatory gas exchange variable responses. In contrast with the classical 3-component model that describes the increase in VO(2) for severe-intensity exercise, we observed a 4(th) phase characterised by a significant decrease in VO(2) before exhaustion (slope of VO(2)-time relationship significantly different from a zero value, p < 0.01) in 7 out of 13 subjects. Following a time delay of 31 +/- 44 s after the decrease in VO(2), a significant decrease of minute ventilation (V(E)) was present for 6 of the 7 subjects (p < 0.02). During the exercise for the subjects who decreased V(E), a reduction of 288 +/- 169 ml in tidal volume was associated with an increase of 10.2 +/- 2.4 min(-1) in breathing frequency. These data suggest that the respiratory system might be stressed more for some endurance-trained athletes. The specific link between reduced VO(2) and reduced V(E) remains to be explored.
Subject(s)
Exercise Tolerance/physiology , Exercise/physiology , Oxygen Consumption/physiology , Running/physiology , Adolescent , Adult , Exercise Test , Humans , Lactic Acid/blood , Male , Models, Biological , Reference Values , TimeABSTRACT
The investigation of self-regulation of grip force provides indirect cues about the developmental neurobiology of the subject. The aim of this study was to examine the ability of subjects of different ages to produce different forces based on their perceived exertion during a grip force task by using a test and a randomised re-test procedure. Eighteen young children (aged 6.5 years), 18 adolescents (13.5 years) and 18 adults (28.5 years) performed a graded hand grip strength test (GST) at four intensities. Perceived exertion (RPE-C) was recorded at the end of each load level. Then, subjects were scheduled for a randomised grip strength test performed in the same experimental conditions than GST. Statistical analysis revealed no significant effect in grip strength for test in the three groups. However, a significant main effect for intensities was obtained in the three groups (P < 0.0001). Significant correlations were observed between GST and RPE-C (r(2) = 0.62, P < 0.0001; r(2) = 0.53, P < 0.0001; r(2) = 0.51, P < 0.0001), in the children, adolescent and adult groups, respectively. However at low grip force intensities, it appears that children have some difficulties to rate their perceived exertion. The results of this study suggest that the neurodevelopmental level of 6-year-old children do not affect the ability to produce reliably moderate to intense forces from perceived exertion during a grip force task.
Subject(s)
Aging , Hand Strength , Physical Exertion , Self Concept , Adolescent , Adult , Aging/physiology , Aging/psychology , Child , Female , Hand Strength/physiology , Humans , MaleABSTRACT
The aims of this study were to test the hypotheses that 1) the aerobic energy cost of roller ski skating (CS) is significantly related to level of performance and 2) a significant part of inter-individual differences of CS can be explained by kinematic parameters of skating locomotion. Oxygen uptake, kinematics of the knee and ankle joint, EMG of the vastus lateralis (VL) and gastrocnemius lateralis (GL) muscles, and roller ski velocity were recorded in 13 skiers who roller skied at 19.0 +/- 0.1 km x h(-1). CS was found to be 2.51 +/- 0.35 J x kg(-1) x m(-1) and significantly correlated with the skiers' level of performance (r = 0.61; p < 0.05). Significant relationships were found between CS and 1) knee angular amplitude (r = 0.75; p < 0.01) during the concentric phase, 2) VL average EMG during the concentric phase (r = 0.72; p < 0.01) and 3) VL and GL average EMG during the eccentric phase (p < 0.05). The results of this study showed that a significant part of performance could be explained by the aerobic energy cost of locomotion in skating. It can also be suggested that differences in upper/lower body utilization and/or in mechanical efficiency may explain the differences in CS.
Subject(s)
Energy Metabolism/physiology , Skating/physiology , Skiing/physiology , Adult , Electromyography , Exercise/physiology , Humans , Kinetics , Lactic Acid/blood , Male , Oxygen Consumption/physiologyABSTRACT
This study investigated the effects of 40-weeks training in swimming, cycling and running on performances in swimming, running and triathlon competitions in four elite triathletes. The training stimulus was calculated using the exercise heart rate. The level of performance was measured in running by a submaximal 30 min run, in swimming by a 5 x 400 m all-out test and subjectively in triathlon competitions. A mathematical model using one to three first order transfer functions linked actual and modelled performances by minimizing the residual sum of squares between them. The relationships between training and performances were significant in running (tau(1) = 20; tau(2) = 10; r = 0.74; p < 0.001) and in swimming (tau(1) = 31; r = 0.37; p = 0.03), supporting the principle of specificity of the training loads. Cross-transfer training effects were identified between cycling and running (tau(1 = )42; r = 0.56; p < 0.001), but not with swimming performances. In addition, the training loads completed in running were shown to have a major effect on performances in triathlon competition (tau(1 = )52; tau(2 = )4; r = 0.52; p < 0.001), indicating that running training is an essential part of triathlon performance. Swimming appears to be a highly specific activity, which does not gain nor provide benefits from/to other activities (i. e. cycling and running). The present study shows that cross-transfer training effects occur between cycling training and running performance in elite triathletes. A similar cross-training effect does not seem to occur for swimming performance.
Subject(s)
Adaptation, Physiological/physiology , Models, Biological , Physical Education and Training/methods , Sports/physiology , Task Performance and Analysis , Transfer, Psychology/physiology , Adult , Bicycling/physiology , Female , Humans , Male , Physical Endurance/physiology , Running/physiology , Swimming/physiologyABSTRACT
The purpose of this study was to investigate the effects of endurance and sprint training on the perception of the optimal pedalling rate during a submaximal cycling exercise. Six subjects specialized in endurance activities and 6 subjects trained in sprinting activities used the model of bicycling at various pedalling rates with the same power output (150W) on a cycle ergometer. Individual 2nd order polynomial relationships were determined between oxygen consumption (VO(2)) and velocity and between rate of perceived exertion (RPE) and velocity. Optimal velocity, with respect to minimum of VO(2) (OV(VO2)) and to minimum of RPE (OV(RPE)), were calculated for all subjects, respectively. The close similarity found between the VO(2)-velocity and the RPE-velocity curves confirmed that the overall RPE was mainly influenced by the central factor. As OV(RPE) and OV(VO2) were not significantly correlated and as OV(RPE) was significantly higher than OV(VO2), other factors than central may also have influenced the RPE. The significant higher OV(RPE) values (p<0.05) observed in the sprint vs. endurance groups suggested that different training background may have influenced the RPE. These differences could also be explained by a significantly higher OV(VO2) in sprint than in endurance groups, the subjects being sensitive to the pedalling rate for which the energy expenditure is minimal.
Subject(s)
Bicycling/physiology , Bicycling/psychology , Physical Education and Training/methods , Physical Endurance/physiology , Physical Exertion/physiology , Adult , Humans , Individuality , Male , Oxygen Consumption/physiology , Task Performance and AnalysisABSTRACT
The purpose of the present study was to examine both the specific and the transfer effects of a Square Wave Endurance Exercise Test (SWEET) and to investigate the determining factors of transfer effect. A control group (CG, n = 5) and 2 experimental groups were studied. Experimental groups completed 3 days/week a 45 min SWEET over 6 weeks, either with the arms using a wheelchair ergometer (AG, n = 5) or with the legs using a cycling ergometer (LG, n = 5). All subjects performed before and after training two maximal progressive tests: the first one with the arms and the second with the legs. During those tests oxygen uptake (VO(2)) and cardiorespiratory parameters were continuously measured. Specific effects (changes between the tests performed with trained limbs) were observed: the peak power output (W(p)) and VO(2) were significantly increased by both arm (+ 66 %, + 35 %) and leg (+ 17 %, + 14 %) training. At ventilatory threshold (VT), power output (W) and VO(2) were significantly increased with arm (+ 145 % and + 51 %) and leg (+ 53 % and + 46 %) training. Transfer effects (changes between pre and post tests performed with untrained limbs) were observed: W(p) and VO(2) were not increased in AG while W(p) was increased in LG (+ 11 %). At VT, W and VO(2) were increased with arm (+ 19 % and + 23 %) and leg (+ 33 % and + 46 %) training. For AG and LG the VO(2) expressed in percent of the VO(2) peak was increased (+ 19 % and + 33 %, respectively) and the O(2p) was also increased (+ 30 %) for LG. These results show that SWEET training induced specific and transfer effects. Moreover, the initial level of the subjects, the type and the intensity of the training seem to be the major factors for effective observable transfer effects.