Effects Of Muscular Fatigue Research Articles

Effects of Muscular Fatigue on Position Sense in Two Phases of the Menstrual Cycle.

It is generally accepted that local muscular fatigue can negatively affect position sense. Interestingly, it has been proposed that in women, position sense and neuromuscular coordination may be affected by fluctuations of estrogen and progesterone levels. The aim of this study was to examine the possible effect of localized muscle fatigue on knee joint position sense at two phases of the menses: follicular and luteal. Twenty physically active females aged 19-30 years, with normal menses, volunteered for this study. An isokinetic dynamometer was used to evaluate proprioception and perform the fatigue protocol of the knee extensors and flexors. Knee proprioception at rest and after fatigue at three knee target angles (30°, 45°, 60°) was measured. A three-way ANOVA analysis with repeated measures was performed. The results showed that the main effect of fatigue was significant, but no main effect of the menstrual cycle phase was found. Additionally, a main effect was found for the target angle (more flexed target knee joint angles were associated with larger angular error deviations). In conclusion, localized muscle fatigue can significantly reduce the accuracy of active knee joint repositioning in both the luteal and the follicular menstrual phases in young, physically active healthy women.

Effect of muscular fatigue on the cumulative lumbar damage during repetitive lifting task: a comparative study of damage calculation methods

Several methods have been put forward to quantify cumulative loads; however, limited evidence exists as to the subsequent damages and the role of muscular fatigue. The present study assessed whether muscular fatigue could affect cumulative damage imposed on the L5–S1 joint. Trunk muscle electromyographic (EMG) activities and kinematics/kinetics of 18 healthy male individuals were evaluated during a simulated repetitive lifting task. A traditional EMG-assisted model of the lumbar spine was modified to account for the effect of erector spinae fatigue. L5–S1 compressive loads for each lifting cycle were estimated based on varying (i.e. actual), fatigue-modified, and constant Gain factors. The corresponding damages were integrated to calculate the cumulative damage. Moreover, the damage calculated for one lifting cycle was multiplied by the lifting frequency, as the traditional approach. Compressive loads and the damages obtained through the fatigue-modified model were predicted in close agreement with the actual values. Similarly, the difference between actual damages and those driven by the traditional approach was not statistically significant (p = 0.219). However, damages based on a constant Gain factor were significantly greater than those based on the actual (p = 0.012), fatigue-modified (p = 0.017), and traditional (p = 0.007) approaches. Practitioner summary: In this study, we managed to include the effect of muscular fatigue on cumulative lumbar damage calculations. Including the effect of muscular fatigue leads to an accurate estimation of cumulative damages while eliminating computational complexity. However, using the traditional approach also appears to provide acceptable estimates for ergonomic assessments.

Quick on Your Feet: Modifying the Star Excursion Balance Test with a Cognitive Motor Response Time Task.

The Star Excursion Balance Test (SEBT) is a common assessment used across clinical and research settings to test dynamic standing balance. The primary measure of this test is maximal reaching distance performed by the non-stance limb. Response time (RT) is a critical cognitive component of dynamic balance control and the faster the RT, the better the postural control and recovery from a postural perturbation. However, the measure of RT has not been done in conjunction with SEBT, especially with musculoskeletal fatigue. The purpose of this study is to examine RT during a SEBT, creating a modified SEBT (mSEBT), with a secondary goal to examine the effects of muscular fatigue on RT during SEBT. Sixteen healthy young male and female adults [age: 20 ± 1 years; height: 169.48 ± 8.2 cm; weight: 67.93 ± 12.7 kg] performed the mSEBT in five directions for three trials, after which the same was repeated with a response time task using Blazepod™ with a random stimulus. Participants then performed a low-intensity musculoskeletal fatigue task and completed the above measures again. A 2 × 2 × 3 repeated measures ANOVA was performed to test for differences in mean response time across trials, fatigue states, and leg reach as within-subjects factors. All statistical analyses were conducted in JASP at an alpha level of 0.05. RT was significantly faster over the course of testing regardless of reach leg or fatigue state (p = 0.023). Trial 3 demonstrated significantly lower RT compared to Trial 1 (p = 0.021). No significant differences were found between fatigue states or leg reach. These results indicate that response times during the mSEBT with RT is a learned skill that can improve over time. Future research should include an extended familiarization period to remove learning effects and a greater fatigue state to test for differences in RT during the mSEBT.

The Effect of Mental and Muscular Fatigue on the Accuracy and Kinematics of Dart Throwing.

In this study, we analyzed the effect of mental and muscular fatigue on the accuracy and kinematics of dart throwing. For this purpose, 28 young adults (19 females and 9 males) aged 25-35years, without any regular experience in dart throwing, participated in this study. We evaluated their dart throwing skills in mental fatigue, muscular fatigue, and non-fatigue conditions. To induce mental fatigue, we used the Stroop task for 70minutes and a simulated dart throwing exercise with an elastic band. In all three conditions, we collected accuracy data, based on the score of the dart on the board and the kinematic properties with a motion capture device. For analyzing the data and testing the research hypotheses, we employed ANOVA analyses with repeated measures after examining the normality of data distributions using skewness and kurtosis. We observed a significant decrease in the accuracy of dart throwing following mental fatigue (p = 0.027) and muscular fatigue (p = 0.001) compared to non-fatigue and following muscular fatigue compared to mental fatigue (p = 0.001). In the kinematic results, we observed a significant difference in the mean velocity of the elbow between different experimental conditions (p = 0.001). This variable decreased due to muscular fatigue, compared to the other two conditions. On the other hand, there was no significant difference among the three experimental conditions for the variables of elbow range of motion, shoulder range of motion, and mean velocity of the shoulder joint. These findings affirm mental and muscular fatigue effects on dart throwing and provide further detail regarding the specific aspects of these effects on dart throwing skills or other fine motor activities.

Acute Effects of Muscular Fatigue on Vertical Jump Performance in Acrobatic Gymnasts, Evaluated by Instrumented Insoles: A Pilot Study

The study of fatigue during training is becoming a very useful tool to avoid possible injuries not only during the training sessions but also during recovery time. Many researches have proved that concepts such as muscular fatigue and postactivation potentiation have a close relationship. With this aim, vertical jump can provide a very important information that can help to analyze the muscular fatigue that happened during this type of activity, mainly if the monitoring system is able to measure jumping parameters during their regular training session in their natural training environment. This study was performed with instrumented insoles called ECnsole. These insoles were tested with a group of twelve volunteers. In a tumbling surface, the participants performed a jumping protocol in three conditions: rest, fatigue‐induced, and recovery. Using these validated insoles, the acrobatic gymnasts showed an inability to use the stretch‐shortening cycle for improving vertical jumping performance after fatigue condition, although no deterioration of jump performance was found.

Effects of a lower limb muscular fatigue on posture-movement interaction during a lower limb pointing task.

The aim of the present study was to investigate the effects of muscular fatigue on the interaction between posture and movement during a lower limb pointing task. Participants (n = 16), aged 18-30years, kicked a ball toward a target in four conditions of fatigue: No muscular fatigue (NF), fatigue in the kicking (FM) or postural limb (FP) alone, and fatigue in both limbs (FMP). The mean amplitude and speed of the centre of foot pressure (CoP) and centre of mass (CoM) displacements were estimated through a force platform and an optoelectronic system, respectively. In addition, surface electromyography (EMG) of the biceps femoris, rectus femoris, medial gastrocnemius, and peroneus longus was recorded to investigate the anticipatory postural adjustments (APAs). Muscular fatigue yielded a decreased kicking accuracy (p < 0.001) and an increased time to perform the movement (p < 0.001), mainly during the backswing motion. In addition, significant increases in the mean amplitude and speed of the CoP and CoM displacement were found in the anteroposterior (AP) and mediolateral (ML) axes (ps < 0.001), especially when both limbs were fatigued. The EMG analysis confirmed that fatigue modified the way APAs were generated. During fatigue, postural muscle activity increased, but was delayed with respect to movement onset (ps < 0.001). This pattern of response was more consistent when both limbs were fatigued (p < 0.001). The present results suggested an additive effect of fatigue and a functional adaptation and subsequent decrease in the overall variability of APAs, indicating that postural and motor processes are interdependent.

Instantaneous interjoint rescaling and adaptation to balance perturbation under muscular fatigue.

Adaptation of automatic postural responses (APR) to balance perturbations might be thought to be impaired by muscle fatigue, given the associated proprioceptive and effector deficits. In this investigation, we aimed to evaluate the effect of muscular fatigue on APR adaptation over repetitive balance perturbations through support base backward translations. APR adaptation was evaluated in three epochs: (a) pre-fatigue; (b) post-fatigue, immediately following fatigue of the plantiflexor muscles through isometric contractions and (c) post-recovery, 30min after the end of fatiguing activity. Results showed the following: (a) Decreasing amplitudes of joints' maximum excursion over repetitive perturbations in the three fatigue-related epochs. (b) Modulation of joints' excursion was observed in the first trial in the post-fatigue epoch. (c) In the post-fatigue epoch, we found interjoint rescaling, with greater amplitude of hip rotation associated with reduced amplitude of ankles' rotation. (d) Amplitudes of ankles' rotation were similar between the post-fatigue and post-recovery epochs. These findings lead to the conclusions that adaptation of automatic postural responses over repetitive trials was effective under focal muscular fatigue; modulation of the postural response took place in the first perturbation under fatigue, and generalization of response characteristics from post-fatigue to post-recovery suggests that feedforward processes in APRs generation are affected by the recent history of postural responses to stance perturbations.

Reference values for fatigued versus non-fatigued limb symmetry index measured by a newly designed single-leg hop test battery in healthy subjects: a pilot study

PurposeThere is sparse evidence for return to sport criteria after knee injury. Functional performance deficits, particularly in fatigued muscular condition, should be verified prior to the attempt to return to high-risk pivoting sports. The purpose of this study was to generate reference values for the limb symmetry index (LSI) of healthy subjects in fatigued and non-fatigued muscular condition in a newly designed test battery.MethodsForty-two healthy subjects [22 females, 20 males; mean (SD) age 30.4 (6.6) years] were evaluated using a test battery consisting of an isometric strength test, a series of five single-leg hop tests and an integrated fatigue protocol. Subjective physical activity was assessed with the Tegner Activity Scale (TAS). The cut-off values for healthy subjects were calculated considering the fifth percentile as the minimum reference value for the LSI and single-leg hop distance.ResultsThe mean (SD) overall LSI was 98.8% (4.6). No significant gender or age specific differences in limb symmetry were observed. The comparison of the non-fatigued LSI with the overall LSI revealed no clinically relevant change due to muscular fatigue. Repeated measures ANOVA revealed a significant within effect on fatigue/non-fatigue condition (F(1,38) = 18.000; p < 0.001, η2 = 0.321) on absolute single-leg hop distance. Moreover, a significant between effect on the TAS-parameter (F(1,38) = 5.928; p = 0.020, η2 = 0.135 between: TAS ≤ 5/TAS > 5) and on gender (F(1,38) = 23.956; p < 0.001, η2 = 0.387) could be detected.ConclusionsThe absolute jumping distance in the single-leg hop for distance was significantly reduced due to fatigue. No clinically relevant effect of muscular fatigue was observed on limb symmetry in our study sample. Gender and physical activity are important factors to be considered when interpreting reference values.

Relationship of EMG and Subjective Discomfort Ratings for Repetitive Handling of Lightweight Loads

Objective: The aim of this study is to evaluate the effect of weight of load and time on the physical workload of repetitive upper-limb tasks with handling light weight loads using EMG and perceived discomfort, and to investigate the relationship between EMG and perceived discomfort for those repetitive tasks of moving light weight loads. Background: Repetitive upper-limb motion is known as one of the main risk factors of musculoskeletal disorders, and a lot of repetitive tasks are carried out while handling light weight loads in the industry. In evaluating the workload of repetitive tasks handling light weight loads, EMG and perceived discomfort can be used, though their relationship in those work conditions are not much investigated. Method: A laboratory experiment with 18 healthy males were conducted to record EMG signals from 5 muscle sites of the right arm and shoulder and rate perceived discomforts for the body parts and the whole body while carrying out repetitive materials-handling tasks for 52min. The subjects were divided into 3 groups which handled the loads of 1kg, 2kg and 3kg, respectively. ANOVAs were conducted to analyze the effects of the weight and time on RMS of EMG amplitude (normalized RMS: NRMS), median frequency of power spectrum of EMG (normalized MDF: NMDF) and perceived discomfort. The correlations between NRMS and NMDF and perceived discomfort were also analyzed. Results: Statistically significant muscular fatigue effects were not found from NRMS and NMDF in most muscles, while there were significant increases of discomfort as the task time elapsed. It was shown that there were an increasing trend of the muscular activity as the weight of load increased and a decreasing trend of median frequency of EMG of upper and lower arms as time elapsed. It was found that there were significant negative correlations between NMDFs from the lower arm and discomfort ratings, though the relationships were weak. Conclusion: It can be concluded that the working conditions adopted in this study were not enough to induce muscular fatigue, while there was significant increase in perceived discomfort. A further study is necessary to integrate the objective and subjective measures for more reliable and sensitive evaluation of workload of repetitive tasks of handling light weight loads. Application: This study can be used as a basic study for the evaluation of workload of repetitive tasks handling light weight loads.

Load carriage by infantry soldiers

At constant speed of marching, oxygen consumption has been found to increase linearly with the amount of load carried, indicating that there is no optimum load. However, an optimum speed of marching has been found, depending on the terrain condition. A different line of approach, involving a study of the relationship between stride-length, frequency of stepping and speed in normal walking and the effect of muscular fatigue on this relationship has also yielded similar results. Desirability of further studies on the effect of load on optimum speed of marching, effective reduction of weight of equipment and optimum distribution of load on the body has been stressed.

Unexperienced mechanical effects of muscular fatigue can be predicted by the Central Nervous System as revealed by anticipatory postural adjustments.

Muscular fatigue effects have been shown to be compensated by the implementation of adaptive compensatory neuromuscular strategies, resulting in modifications of the initial motion coordination. However, no studies have focused on the efficiency of the feedforward motor commands when muscular fatigue occurs for the first time during a particular movement. This study included 18 healthy subjects who had to perform arm-raising movements in a standing posture at a maximal velocity before and after a fatiguing procedure involving focal muscles. The arm-raising task implies the generation of predictive processes of control, namely Anticipatory Postural Adjustments (APAs), whose temporal and quantitative features have been shown to be dependent on the kinematics of the upcoming arm-raising movement. By altering significantly the kinematic profile of the focal movement with a fatiguing procedure, we sought to find out whether APAs scaled to the lower mechanical disturbance. APAs were measured using surface electromyography. Following the fatiguing procedure, acceleration peaks of the arm movement decreased by ~27%. APAs scaled to this lower fatigue-related disturbance during the very first trial post-fatigue, suggesting that the Central Nervous System can predict unexperienced mechanical effects of muscle fatigue. It is suggested that these results are accounted for by prediction processes in which the central integration of the groups III and IV afferents leads to an update of the internal model by remapping the relationship between focal motor command magnitude and the actual mechanical output.

2A2-B04 表面筋電位のパターンエントロピー分析による筋疲労の定量評価(感覚・運動・計測(2))

Surface electromyography (SEMG) has been used to detect the muscular activity in the field of biomechanics. By the way, the effects of muscular fatigue on SEMG have been studied and some frequency analysis methods such as first Fourier transform (FFT) and continuous wavelet transform (CWT) found the quantitative and qualitative alternation appear on the time-series of SMEG. However, it is difficult to estimate muscular fatigue quantitatively from SEMG analysis yet. Then, this study focuses on the pattern entropy method that compresses time-series signal with focusing on the instability, and attempts to apply this method to SEMG in order to quantitatively estimate the effect of muscular fatigue onto time-series signal of SEMG. The possibilities of the pattern entropy method to evaluate muscular fatigue from SEMG are discussed with comparing to the time-series data of power spectrum coefficient and frequency coefficient of the resut of gabor's CWT.

Effect of the Height of a Wheelchair on the Shoulder and Forearm Muscular Activation During Wheelchair Propulsion

[Purpose] The activations of the shoulder muscle and forearm muscle were analyzed at different chair heights with reference to the user’s elbow joint flexion angle to provide fundamental kinematic data for the fabrication of wheelchairs suitable for the elderly and the disabled with spinal damage. [Subjects] Participants who met the criteria for this study (n=12). [Methods] Muscular activity was measured during propulsion of a wheelchair with chair heights corresponding to elbow flexion angles of 0, 30, 60 and 90 degrees. To eliminate the effect of muscular fatigue, that might have been caused during wheelchair propulsion. [Results] The biceps brachii, anterior deltoid, pectoralis major, serratus anterior and latissimus dorsi muscle activation showed significant differences. [Conclusion] On the basis of the results of this study, we consider that excessive load on the shoulder muscles should be reduced by producing wheelchairs with adjustable chair heights and by using a wheelchair with consideration for an individual’s body size. Future studies should be conducted on the somatic muscle activation at different on chair heights and on the appropriate chair height for various external environments such as a slopeway.

A single bout of resistance exercise does not affect nonlinear dynamics of lower extremity kinematics during treadmill walking

Peripheral fatigue has been known to result in altered force output and muscle recruitment patterns by the CNS. These changes may affect lower extremity movement during gait, and such behavior may present implications for the interpretation of nonlinear analysis of gait in situations where a subject might become fatigued. The purpose of this study was to examine the effects of a single bout of resistance training on lower extremity movement during treadmill walking in healthy subjects. Fifteen recreationally active subjects performed two 10 min trials of treadmill walking at their preferred speed while knee and ankle kinematics of their right limb were recorded via optical motion capture. Between walking trials, subjects performed a series of lower extremity resistance exercises designed to induce moderate muscular fatigue. Detrended fluctuation analysis of stride length and stride time revealed that statistical persistence was unaffected by moderate muscle fatigue. Estimates of finite-time maximal Lyapunov exponents for ankle angle, knee angle, and vertical ankle movement over the short (0–1 stride) and long (4–10 strides) term were also unaffected by a single bout of resistance training. These results suggest that control of locomotion in healthy individuals, as measured by the nonlinear dynamics of lower extremity movement used here, is relatively robust to moderate muscle fatigue. Additional work with greater levels of fatigue will be necessary to fully characterize the effects of muscular fatigue on gait.

Local State Space Temporal Fluctuations: A Methodology to Reveal Changes During a Fatiguing Repetitive Task

The effect of muscular fatigue on temporal and spectral features of muscle activities and motor performance, i.e., kinematics and kinetics, has been studied. It is of value to quantify fatigue related kinematic changes in biomechanics and sport sciences using simple measurements of joint angles. In this work, a new approach was introduced to extract kinematic changes from 2D phase portraits to study the fatigue adaptation patterns of subjects performing elbow repetitive movement. This new methodology was used to test the effect of load and repetition rate on the temporal changes of an elbow phase portrait during a dynamic iso-inertial fatiguing task. The local flow variation concept, which quantifies the trajectory shifts in the state space, was used to track the kinematic changes of an elbow repetitive fatiguing task in four conditions (two loads and two repetition rates). Temporal kinematic changes due to muscular fatigue were measured as regional curves for various regions of the phase portrait and were also expressed as a single curve to describe the total drift behavior of trajectories due to fatigue. Finally, the effect of load and repetition rate on the complexity of kinematic changes, measured by permutation entropy, was tested using analysis of variance with repeated measure design. Statistical analysis showed that kinematic changes fluctuated more (showed more complexity) under higher loads (p=0.014), but did not differ under high and low repetition rates (p=0.583). Using the proposed method, new features for complexity of kinematic changes could be obtained from phase portraits. The local changes of trajectories in epochs of time reflected the temporal kinematic changes in various regions of the phase portrait, which can be used for qualitative and quantitative assessment of fatigue adaptation of subjects and evaluation of the influence of task conditions (e.g., load and repetition rate) on kinematic changes.

Robust EMG pattern recognition to muscular fatigue effect for powered wheelchair control

The main goal of this paper is to design an electromyogram (EMG) pattern classifier which is robust against muscular fatigue effects for powered wheelchair control. When a user operates a powered w...

Cognitive cost of motor reorganizations associated with muscular fatigue during a repetitive pointing task

Muscular fatigue is known to impair motor performance and to catalyse the development of upper limb musculoskeletal disorders. In order to delay the deleterious effects of muscular fatigue, the central nervous system (CNS) employs compensatory strategies. The cognitive cost of such compensatory strategies was assessed in 10 male subjects who alternatively performed two dual-task protocols before and immediately after an exhaustion procedure specific to upper arm abductor musculature. The main motor tasks were an isometric force-matching and a rapid multi-joint pointing. A secondary probe reaction time (RT) task was performed during both protocols and served as an indicator of attentional demands. Overall motor task performance was maintained despite fatigue. Kinematic and electromyographic data revealed that subjects used motor reorganization during the pointing task when fatigued. The RT increased with fatigue in both dual-task protocols, but this increase was significantly higher during the pointing task than during the force-matching task. The results highlight that the motor reorganization used by the CNS under muscular fatigue states require higher attentional demands than the initial motor organization. Finally, the capacity to delay the deleterious effects of muscular fatigue seems to depend on the proportion of cognitive resources available to plan the compensatory motor strategy.

Theoretical advances and applications of intelligent paradigms

What is an “intelligent paradigm”? While it is difficult to provide an exact definition for this term, the interests in intelligent paradigms research generally focus on designing and developing of computerized machines or systems that exhibit the capabilities of learning from experience, adapting to the surrounding environment, as well as understanding and controlling ones thinking or reasoning process. These are some crucial characteristics of intelligent paradigms so that they can be deployed as usable and useful tools to assist humans in daily activities. Indeed, recent research and development in intelligent paradigms has opened up the way for a number of theoretical advances and successful applications of intelligent techniques and approaches in various domains. Diverse intelligent paradigms are available in the literature, encompassing, to name a few, artificial neural networks, evolutionary algorithms, multiagent systems, artificial immune systems, swarm intelligence, knowledge-based systems, case-based reasoning, as well as hybrid intelligent systems in which these paradigms are contained. Applications of intelligent paradigms also span across various fields, covering, to name a few, information processing, decision making, control and robotics, industrial and medical diagnosis, data mining, e-learning and e-commerce, knowledge management, as well as virtual reality and multimedia. In this special issue, a total of eight articles are collected to showcase a small fraction of some recent advances in theory and application of intelligent paradigms. These articles present research into various intelligent paradigms, with their effectiveness in tackling different real-world problems demonstrated and discussed. A brief outline of each article is as follows. A powered wheelchair is an effective vehicle to help elderly or handicapped people move around the ordinary areas. Song et al. design of an electromyogram (EMG) pattern classifier that is robust against muscular fatigue effects for powered wheelchair control. It is discovered that variations of feature values owing to the effect of muscular fatigue are consistent for sustained duration. This finding leads to a new fatigue compensation method, and the fuzzy Min-Max neural network is employed as a robust EMG-based pattern classifier through the adaptation process of its hyperboxes. The proposed approach demonstrates improved performance for continuous control of powered wheelchair. Path planning is a fundamental problem in mobile robotics. The work by Chakraborty et al. addresses the issue of multi-robot path planning by using parallel differential evolution algorithms. Both centralized and distributed realizations for multi-robot path planning are studied, and the performances of the methods are compared with respect to a few pre-defined yardsticks. Most industrial plants are complex, nonlinear, time varying with time delay, and difficult to control. A fuzzy logic-based system is suitable for their control as it combines measurements, experts’ knowledge and op-

Robust EMG pattern recognition to muscular fatigue effect for powered wheelchair control

The main goal of this paper is to design an electromyogram (EMG) pattern classifier which is robust against muscular fatigue effects for powered wheelchair control. When a user operates a powered wheelchair using EMG-based interface for a long time, muscular fatigue often arises from sustained duration of muscle contraction. The recognition rate thus is degraded and controlling wheelchair gets more difficult. In this paper, an important observation is addressed that the variations of feature values due to the effect of the muscular fatigue are consistent for sustained duration. Based on this observation, we design a robust pattern classifier through the adaptation process of hyperboxes of Fuzzy Min-Max Neural Network. We present, as a result, a significantly improved performance in terms of the continuous usage of wheelchair.

Anticipatory postural control following fatigue of postural and focal muscles

Objective To investigate the effect of fatigue of postural and focal muscles on anticipatory postural adjustments (APAs). Methods Nine healthy adults performed rapid bilateral arm raising movements before and after isometric hamstring (postural) and deltoid (focal/prime mover) muscle fatigue. Muscle force and peak acceleration of the arm movements were recorded to assess the presence of fatigue. Ground reaction forces, EMG activity of trunk and leg muscles and center of pressure (COP) displacements were recorded and quantified within the time intervals typical of APAs. Results Early APA onset was seen in erector spinae and semitendinosus muscles post-deltoid fatigue. Anticipatory EMG integrals were reduced in the semitendinosus muscle post-hamstring fatigue, and were increased in the gastrocnemius muscle post-deltoid fatigue. No changes in COP displacement were observed following fatigue of both muscle groups. Conclusion A common pattern of APA adaptations seen following fatigue of either muscle groups along with no changes observed in COP displacements emphasizes the efficiency of the CNS in maintaining dynamic postural stability in the presence of fatigue. Significance The outcome of the study is important for better understanding of the effect of muscular fatigue on feedforward mechanisms of postural control with possible implications for the elderly and individuals with neurological disorders.