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1.
The present study aimed to investigate the effects of a standardized fatiguing protocol on central and peripheral fatigue in knee-flexors and knee-extensors. Thirteen healthy men (age: 23?±?3 years; height: 1.78?±?0.09 m; body-mass: 73.6?±?9.2?kg) volunteered for the present study. Maximal voluntary contraction (MVC), Electromyography (EMG) activity, voluntary activation level (VAL) as an index of central fatigue and twitch potentiation as an index of peripheral fatigue were measured before and after the fatiguing protocol. The fatiguing protocol consisted of a 0.6 duty-cycle to exhaustion (6?s isometric contraction, 4?s recovery) at 70% MVC. After the fatiguing protocol, MVC decreased in both (Effect-size (ES)?=?1.14) and knee-extensors (ES?=?1.14), and EMG activity increased in both knee-flexors (ES?=?2.33) and knee-extensors (ES?=?1.54). Decreases in VAL occurred in knee-flexors (ES?=?0.92) but not in knee-extensors (ES?=?0.04). Decreases in potentiation occurred in both knee-flexors (ES?=?0.84) and knee-extensors (ES?=?0.58). The greater central occurrence of fatigue in knee-flexors than in knee-extensors may depend on the different muscle morphology and coupled with a greater tolerance to fatigue in knee-extensors. The present data add further insight to the complicated knee-flexors-to-knee-extensors strength relationship and the mechanisms behind the different occurrence of fatigue.  相似文献   

2.
This study investigated the relationships between aerobic characteristics and (i) neuromuscular fatigue induced by 2-min sustained isometric maximal voluntary contractions (MVC) and (ii) subsequent recovery, in the upper and lower limbs. In a pseudo-randomized order, eleven healthy males completed four sessions on different days: maximal incremental cycling test (100 W + 40 W every 2 min); maximal arm-cranking test (50 W + 20 W every 2 min); and 2-min sustained isometric MVCs of the knee extensors (KE) and elbow flexors (EF). Neuromuscular assessment was performed with transcranial magnetic and peripheral nerve stimulation to evaluate central and peripheral neuromuscular factors of fatigue and the subsequent recovery. Peak oxygen uptake, gas exchange threshold and the corresponding power outputs were correlated with recovery of voluntary force after the 2-min KE MVC. Regression analysis showed that power output at the gas exchange threshold alone explained 72% of the variability in ?recovery of KE voluntary force. No relationships with fatigue or recovery in EF were observed. These results suggest that participants with greater aerobic capacities experience the same amount of fatigue and faster recovery of voluntary force in KE but not EF. The potential reasons behind the relationship in KE but not EF are discussed.  相似文献   

3.
Abstract

Non-local muscle fatigue has been demonstrated with unilateral activities, where fatiguing one limb alters opposite limb forces. Fewer studies have examined if non-local fatigue occurs with unrelated muscles. The purpose of this study was to investigate if knee extensors fatigue alters elbow flexors force and electromyography (EMG) activity. Eighteen males completed a control and fatiguing session (randomised). Blood lactate was initially sampled followed by three maximal voluntary contractions (MVC) with the elbow flexors and two with the knee extensors. Thereafter, subjects either sat (control) or performed five sets of bilateral dynamic knee extensions to exhaustion using a load equal to the dominant limb MVC (1-min rest between sets). Immediately afterwards, subjects were assessed for blood lactate and unilateral knee extensors MVC, and after 1 min performed a single unilateral elbow flexor MVC. Two minutes later, subjects performed 12 unilateral elbow flexor MVCs (5 s contraction/10 s rest) followed by a third blood lactate test. Compared to control, knee extensor force dropped by 35% (p < 0.001; ES = 1.6) and blood lactate increased by 18% (p < 0.001; ES = 2.8). Elbow flexor forces were lower after the fatiguing protocol only during the last five MVCs (p < 0.05; ES = ～0.58; ～5%). No changes occurred between conditions in EMG. Elbow flexor forces significantly decreased after knee extensors fatigue. The effect was revealed during the later stages of the repeated MVCs protocol, demonstrating that non-local fatigue may have a stronger effect on repeated rather than on single attempts of maximal force production.  相似文献   

4.
The aim of this study was to assess the effect of a unilateral anterior cruciate ligament reconstruction (ACLR) on maximum voluntary contraction (MVC) and explosive strength of both the involved limb and the uninvolved limb. Nineteen male athletes completed a standard isometric testing protocol 4 months post-ACLR, while 16 healthy participants served as a control group (CG). The explosive strength of the knee extensors and flexors was assessed as RFD obtained from the slope of the force–time curves over various time intervals. Both muscle groups of the involved limb had significantly lower MVC compared to the uninvolved. The involved limb also had significantly lower RFD in the late phase of contraction (140–250 ms) for both knee extensors and flexors (P < 0.05). There was no difference in MVC between the uninvolved limb and the CG. However, RFD of the uninvolved limb was lower compared to CG for both knee extensors (0–180 ms; P < 0.01) and flexors (0–150 ms; P < 0.05). ACLR leads to lower MVC and explosive strength of the involved limb. As a consequence of potential crossover (presumably neural-mediated) effects, explosive strength deficits could be bilateral, particularly in the early phase of the contraction (<100 ms).  相似文献   

5.
The hypothesis, that sailing upwind in wind speeds above 12 knots causes fatigue, which manifests as a reduction in exerted hiking strap force and/or maximal isometric voluntary contraction force (MVC) of the knee extensors, was evaluated. Additionally, it was investigated if a relationship exists between maximal exerted hiking force (hMVC) and sailing performance. In part 1 of the study, 12 national level athletes sailed upwind for 2?×?10?min while hiking strap forces were continuously acquired. Before, in between and after sailing periods, the MVC of the knee extensors was measured. In part 2 of the study, hMVC was measured dry land in a hiking bench and correlated with the overall results at a national championship. Hiking strap force decreased from the first to the last minute in both 10?min sailing periods (430?±?131 vs. 285?±?130?N, P?<?.001 and 369?±?74 vs. 267?±?97 N, P?<?.001, respectively), but MVC was similar before, between and after the two 10?min sailing periods (878?±?215 vs. 852?±?202 vs. 844?±?211 130?N). In part 2, a significant positive correlation (r2?=?0.619, P?<?.01) was observed between hMVC and regatta results. In conclusion, upwind sailing in wind speeds above 12 knots causes sailing-specific fatigue as evidenced by a marked reduction in exerted hiking strap force. However, MVC of the knee extensors was not compromised ～45?s after hiking was terminated. Additionally, sailing performance is related to maximal hiking force.  相似文献   

6.
This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising torque. Twenty healthy men were assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180°s-1. Maximal isometric knee extensor torque (MVC) and incremental RFD in successive 50 ms time-windows from the onset contraction were analysed in absolute terms (RFDINC) or when normalised relative to MVC (RFDREL). After eight weeks, TG demonstrated increases in MVC (28%), RFDINC (0–50 ms: 30%; 50–100 ms: 31%) and RFDREL (0–50 ms: 29%; 50–100 ms: 32%). Moreover, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL obtained at the early phase of rising joint torque.  相似文献   

7.
This study investigated the time needed to change a motor program that specified the elbow flexor muscles to gradually increase the isometric force production from 15% to 75% of one's maximum voluntary contraction (MVC). A double-stimulation paradigm was used with the restriction that subjects (N = 12) be at 15% of their MVC before the presentation of the first stimulus. Subjects reacted to the first stimulus (randomly presented) by gradually increasing their isometric force from 15% to 75% of their MVC and then reacted to the second stimulus by altering the force production in one of four ways: (a) increasing the force to the 75% level rapidly instead of gradually, (b) discontinuing the increase and maintaining the level of force attained, (c) discontinuing all force production, or (d) reversing the direction of force so that it is produced by the elbow extensors. The data revealed that more time was needed to increase the force rapidly than to perform any of the other three conditions.  相似文献   

8.
Abstract

The main aim of this study was to assess neuromuscular fatigue during a typical high-load, low-repetition loading protocol. Muscle stimulations were used to assess maximum voluntary contraction, resting single- and double-pulse twitch characteristics, and superimposed double-pulse twitch force (used to calculate voluntary activation) before and after an acute knee extension loading protocol. In our participants, who had previous resistance training experience, the mean voluntary activation level was 96.2% in an unfatigued state. Maximum voluntary contraction (?11.8%), resting double-pulse twitch force (?10.6%), and voluntary activation (?2.1%) were markedly decreased as a consequence of loading (P < 0.05). In addition, although potentiated twitch characteristics were observed during the loading protocol, this was short-lived, as fatigue surpassed the potentiation mechanisms. Our results show that both central and peripheral mechanisms contributed to neuromuscular fatigue during the present loading protocol.  相似文献   

9.
Abstract

This study investigated the time needed to change a motor program that specified the elbow flexor muscles to gradually increase the isometric force production from 15% to 75% of one's maximum voluntary contraction (MVC). A double-stimulation paradigm was used with the restriction that subjects (N = 12) be at 15% of their MVC before the presentation of the first stimulus. Subjects reacted to the first stimulus (randomly presented) by gradually increasing their isometric force from 15% to 75% of their MVC and then reacted to the second stimulus by altering the force production in one of four ways: (a) increasing the force to the 75% level rapidly instead of gradually, (b) discontinuing the increase and maintaining the level of force attained, (c) discontinuing all force production, or (d) reversing the direction of force so that it is produced by the elbow extensors. The data revealed that more time was needed to increase the force rapidly than to perform any of the other three conditions.  相似文献   

10.
Abstract

Match-induced fatigue of knee muscle strength and agonist-antagonist strength-ratios may affect both performance and risk of injury in soccer players. Once explosive tasks are imperative in soccer as well as hamstring strain injuries occur during high-velocity moments, rapid force capacity of this muscle group is especially important. This study evaluated the effect of match-induced fatigue on knee muscle strength and strength-ratio parameters after a single professional soccer match. Male professional soccer players (n?=?16; 24.2?±?3.9 years) were tested before and after a soccer match (56.2?±?22.6?min of playing) for knee flexors (hamstring) and extensors (quadriceps) isometric peak torque (MVC) and rate of torque development (RTD) – as well as the hamstring-to-quadriceps ratio (H:Q) – at 30° of knee flexion. Knee injuries often occur at this joint angle, which is common in sprinting, pivoting, sidecutting, and jumping. Match-induced fatigue caused a left shift in the knee extensors torque-time curve with no significant change in both early (i.e. 0–50?ms) and late (i.e. 0–200?ms) RTD, and a right shift in the knee flexors torque-time curve with a decrease in early RTD (～16%, p?=?.029) and late RTD (～11%, p?=?.011). Knee extensors and knee flexors peak torque remained unchanged (p?>?.05). Early RTD H:Q decreased by～24% (p?=?.027), while late RTD H:Q and MVC H:Q remained unchanged (p?>?.05). In conclusion, match-induced fatigue impaired the ability to rapidly produce force at an angle where injuries are most susceptible to occur. Important information is missed if only the traditional H:Q is considered.  相似文献   

11.
Abstract

The temporal structure, or complexity, of muscle torque output reflects the adaptability of motor control to changes in task demands. This complexity is reduced by neuromuscular fatigue during intermittent isometric contractions. We tested the hypothesis that sustained fatiguing isometric contractions would result in a similar loss of complexity. To that end, nine healthy participants performed, on separate days, sustained isometric contractions of the knee extensors at 20% MVC to task failure and at 100% MVC for 60?s. Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling were quantified by calculating approximate entropy (ApEn) and the detrended fluctuation analysis (DFA) α scaling exponent. Global, central and peripheral fatigue were quantified using maximal voluntary contractions (MVCs) with femoral nerve stimulation. Fatigue reduced the complexity of both submaximal (ApEn from 1.02?±?0.06 to 0.41?±?0.04, P?<?0.05) and maximal contractions (ApEn from 0.34?±?0.05 to 0.26?±?0.04, P?<?0.05; DFA α from 1.41?±?0.04 to 1.52?±?0.03, P?<?0.05). The losses of complexity were accompanied by significant global, central and peripheral fatigue (all P?<?0.05). These results demonstrate that a fatigue-induced loss of torque complexity is evident not only during fatiguing intermittent isometric contractions, but also during sustained fatiguing contractions.  相似文献   

12.
BackgroundFemales are typically less fatigable than males during sustained isometric contractions at lower isometric contraction intensities. This sex difference in fatigability becomes more variable during higher intensity isometric and dynamic contractions. While less fatiguing than isometric or concentric contractions, eccentric contractions induce greater and longer lasting impairments in force production. However, it is not clear how muscle weakness influences fatigability in males and females during sustained isometric contractions.MethodsWe investigated the effects of eccentric exercise-induced muscle weakness on time to task failure (TTF) during a sustained submaximal isometric contraction in young (18–30 years) healthy males (n = 9) and females (n = 10). Participants performed a sustained isometric contraction of the dorsiflexors at 35° plantar flexion by matching a 30% maximal voluntary contraction (MVC) torque target until task failure (i.e., falling below 5% of their target torque for ≥2 s). The same sustained isometric contraction was repeated 30 min after 150 maximal eccentric contractions. Agonist and antagonist activation were assessed using surface electromyography over the tibialis anterior and soleus muscles, respectively.ResultsMales were ∼41% stronger than females. Following eccentric exercise both males and females experienced an ∼20% decline in maximal voluntary contraction torque. TTF was ∼34% longer in females than males prior to eccentric exercise-induced muscle weakness. However, following eccentric exercise-induced muscle weakness, this sex-related difference was abolished, with both groups having an ∼45% shorter TTF. Notably, there was ∼100% greater antagonist activation in the female group during the sustained isometric contraction following exercise-induced weakness as compared to the males.ConclusionThis increase in antagonist activation disadvantaged females by decreasing their TTF, resulting in a blunting of their typical fatigability advantage over males.  相似文献   

13.
Abstract

The force enhancement of muscle twitch contraction after a maximal voluntary contraction (MVC) has been defined as post-activation potentiation. However, the effects of post-activation potentiation on ballistic movements have not been studied extensively, or the underlying neurophysiologycal mechanism. In the current study, we examined post-activation potentiation and spinal H-reflex excitability in the soleus muscle. Mechanical power during explosive ballistic plantar flexions was measured in 14 males before and after 5 s, 4 min, and 10 min of isometric conditioning (EPFpre, EPF5s, EPF4min, EPF10min, respectively). Four sessions corresponding to four different protocols of isometric conditioning were conducted. The protocols were different in the intensity (10% vs. 100% of MVC) and duration (7 vs. 10 s) of the isometric conditioning. The results showed a significant enhancement in mechanical power in EPF4min compared with EPFpre, only when the isometric conditioning was performed at 100% of MVC for 10 s. No significant changes were observed in the H-related parameters (e.g amplitude, threshold, H/M ratio) after the isometric conditioning. Our results show that to obtain a post-activation potentiation during explosive ballistic movements, the intensity and duration of the isometric conditioning must be controlled. Moreover, the improvement in mechanical power is not related to spinal H-reflex excitability.  相似文献   

14.
Abstract

The purpose of this study was to compare twitch contractile properties of skeletal muscles in male athletes who train for power and endurance simultaneously (Nordic combined athletes) with athletes who train for endurance (cross-country skiers) and sedentary individuals. Ten Nordic combined athletes, 13 cross-country skiers, and 14 sedentary males aged 20–26 years participated. To determine the contractile properties of the plantarflexor muscles during isometric twitch, the posterior tibial nerve in the popliteal fossa was stimulated by supramaximal square wave pulses of 1 ms duration. Twitch peak force, maximal rates of force development and relaxation, contraction and half-relaxation times were measured. The percentage increase in twitch peak force after a 5-s maximal voluntary contraction (MVC) was taken as an indicator of post-activation potentiation. Nordic combined athletes had a significantly greater twitch post-activation potentiation and rate of force development and shorter contraction time than the other two groups (P < 0.05). They also had a greater (P < 0.05) twitch peak force than cross-country skiers. No significant differences in measured twitch contraction characteristics were found in cross-country skiers and sedentary males. We conclude that the twitch contractile properties of the plantarflexor muscles differed markedly in athletes who train for power and endurance simultaneously compared with athletes who predominantly train for endurance. As an indicator of long-term adaptation to simultaneous power and endurance training, increased twitch force-generation and potentiation capacity, and shortening of twitch contraction times in the plantarflexor muscles were observed in Nordic combined athletes.  相似文献   

15.
Objective: The acute responses to resistance training (RT) between males and females are poorly understood, especially from a neural perspective. Therefore, we aimed to compare the corticospinal and intracortical responses during fatigue and recovery following RT.

Methods: Twenty-two participants (12M, 10F) completed one-session of RT (3?×?12 repetition maximum) unilateral leg extensions with 60?s recovery. Single- and paired-pulse transcranial magnetic stimulation measured changes in the motor-evoked potential (MEP), corticospinal silent period (CSP), CSP/MEP ratio, and intracortical facilitation/inhibition (ICF, SICI). The maximal compound wave (MMAX) measured peripheral excitability of the rectus femoris (RF) and maximal voluntary isometric contraction (MVIC) neuromuscular function of the leg extensors. Measures were taken immediately post, 30?min, 1 and 6?h post-training.

Results: A significantly greater increase in MEP/MMAX ratio (p?=?.005) was observed for females immediately post-training compared to males. While no sex differences in MEP/MMAX ratio was observed at 30?min and 1?h post-training, a greater MEP/MMAX ratio for males was observed at 30?min (p?p?=?.003). CSP trended to decrease for males compared to females immediately post-training (d?=?1.93). MVIC was decreased post-training for males; 14.22% and females; 14.16% (P?MAX reduced at 30?min for both groups (P?P?>?.05).

Conclusion: The net output of corticospinal excitability is similar between males and females during fatigue. However, the mechanism in which this is modulated (increased MEP, decreased CSP) appears to be sex-specific.  相似文献   

16.
We investigated the association between changes in vastii electromyography (EMG) and knee extensor fatigue during high-intensity cycling, and the subsequent effect on lower-limb power and intermuscular coordination during all-out cycling. On two separate days, participants completed 30-s all-out cycling or 10-min of high-intensity cycling followed by 30-s all-out cycling. EMG for gluteus maximus (GMAX), rectus femoris (RF), vastii (VAS), hamstrings (HAM) and gastrocnemius (GAS); co-activation for GMAX/RF, VAS/HAM and VAS/GAS; isometric maximal voluntary force (IMVF) and resting twitch (RT) of the knee extensors were measured. VAS EMG increases during high-intensity cycling (6% to 14%, P < 0.05) were negatively correlated (r = ?0.791, P < 0.05) with knee extensor IMVF decreases (?2% to?36%, P < 0.05) following the exercise. Knee extensor IMVF decreases were positively correlated (r = 0.757, P < 0.05) with all-out cycling power reductions (0% to ?27%, P < 0.05). VAS/GAS co-activation did not change (P > 0.05) during all-out cycling while VAS and GAS EMG decreased. Larger increase in VAS EMG during high-intensity cycling was associated with greater knee extensor fatigue and larger power reduction during all-out cycling. High VAS/GAS co-activation potentially limited power reduction induced by knee extensor fatigue during all-out cycling.  相似文献   

17.
Abstract

Twenty-eight young, adult women were tested for maximum voluntary contraction (MVC) of the grip flexors and were then given five fatigue trials in which the task was to maintain a maximum isometric contraction until the strength level had been degraded to either 80%, 60%, or 40% MVC. At that time, the subject relaxed and within one second was commanded to generate a single contraction as rapidly and forcefully as possible. Testing was also conducted in the nonfatigued state (1.00 MVC). Forces were determined at 4, 8, 16, 32, 64, 128, 256, 512, and 1,024 msec following the initial deflection of the pen from the baseline. Normalized force values were calculated by dividing the force expressed at the various time intervals by the maximum force generated under that condition at 1,024 msec. For both absolute and normalized rate of force development, the highest rate was attained between 32–64 msec. During that time period, the rate of absolute force development was reduced 10% at the 80% MVC level, 30% at 60% MVC, and 53% at 40% MVC. There was a definite pattern of depressed rate of absolute force development up to 256 msec at the higher fatigue levels. For normalized force, fatiguing a muscle to 80% MVC had no effect except at 64 msec where a greater percentage of maximal force was attained than at 1.00 MVC. Beyond that level of fatigue, however, normalized force tended to be adversely affected as fatigue progressed. The time required to develop either 50% or 70% of maximal force was significantly longer for the 40% MVC level than for the remaining conditions. In addition, the time necessary to develop 70% of maximal force was longer for the 60% MVC fatigue level than for the 80% MVC level.  相似文献   

18.
This study compared knee angle-specific neuromuscular adaptations after two low-volume isometric leg press complex training programmes performed at different muscle lengths. Fifteen young males were divided into two groups and trained three times per week for 6 weeks. One group (n?=?8) performed 5–7 sets of 3 s maximum isometric leg press exercise, with 4?min recovery, with knee angle at 85°?±?2° (longer muscle-tendon unit length; L-MTU). The other group (n?=?7) performed the same isometric training at a knee angle of 145°?±?2° (180°?=?full extension; shorter muscle-tendon unit length; S-MTU). During the recovery after each set of isometric exercise, participants performed two CMJ every minute, as a form of complex training. Maximum isometric force (MIF) and rate of force development (RFD) were measured over a wide range of knee angles. Countermovement jump (CMJ) performance and maximum half-squat strength (1RM) were also assessed. Training at S-MTU induced a large increase of MIF (22–58%, p?p?p?=?0.001). In contrast, training at L-MTU, resulted in a moderate and similar (≈12.3%, p?=?0.028) improvement of force at all knee angles. CMJ performance and 1RM were equally increased in both groups after training by 10.4%?±?8.3% and 7.8%?±?4.7% (p?相似文献   

19.
This investigation examined effects of two exercise modes (barbell, BB; bodyweight suspension, BWS) on muscle activation, resistance load, and fatigue. During session one, nine resistance-trained males completed an elbow flexion one-repetition maximum (1RM). During sessions two and three, subjects completed standing biceps curls to fatigue at 70% 1RM utilizing a randomized exercise mode. Surface electromyography (sEMG) recorded muscle activation of the biceps brachii, triceps brachii, anterior deltoid, posterior deltoid, rectus abdominis, and erector spinae. BWS resistance load was measured using a force transducer. Standing maximal voluntary isometric contractions of the elbow flexors recorded at 90° were used to determine the isometric force decrement and rate of fatigue (ROF) during exercise. sEMG and resistance load data were divided into 25% contraction duration bins throughout the concentric phase. BWS resulted in a 67.7?±?7.4% decline in resistance load throughout the concentric phase (p?≤?0.05). As a result, BB elicited higher mean resistance loads (31.4?±?4.0?kg) and biceps brachii sEMG (84.7?±?27.8% maximal voluntary isometric contractions, MVIC) compared with BWS (20.4?±?3.4?kg, 63.4?±?21.6% MVIC). No difference in rectus abdominis or erector spinae sEMG was detected between exercise modes. Isometric force decrement was greater during BWS (?21.7?±?7.0?kg) compared with BB (?14.9?±?4.7?kg); however, BB (?3.0?±?0.8?kg/set) resulted in a steeper decline in ROF compared with BWS (?1.7?±?0.6?kg/set). The variable resistance loading and greater isometric force decrement observed suggest that select BWS exercises may resemble variable resistance exercise more than previously considered.  相似文献   

20.
ABSTRACT

This study aimed to evaluate responsiveness (ability to detect change) of isometric force-time measures to neuromuscular fatigue in resistance-trained participants using two differing protocols that modified both the instructions provided to participants and the duration of the test. Both protocols were completed at two knee joint angles in the isometric squat test. Ten participants volunteered to take part in this study (age: 27.0 ± 4.5 years, strength training experience: 7.7 ± 2.6 years). Isometric peak force (ISqTpeak) and isometric explosive force (ISqTexp) test protocols were assessed at two joint angles (knee angle 100° and 125°) pre-high intensity strength training, immediately post strength training, 24-h post, 48-h post and analysed for peak and RFD performance. Participants completed eight sets of three repetitions of the back-squat exercise as the high-intensity strength training. Results showed the highest standardised response means (SRM) detected was peak force using the ISqTpeak 100, SRM ?1.97 compared to an SRM of ?1.31 for RFD 200 ms in the ISqTexp 125. Peak force was the most responsive variable using the ISqTpeak protocol, whereas the ISqTexp protocol was most responsive for RFD measures. Therefore, ISqTpeak and ISqTexp test protocols should not be used interchangeably to evaluate RFD variables.  相似文献   

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