Search

BACKGROUND: Cerebral palsy (CP) is a collection of disorders that impede an individual’s capacity to execute voluntary movements and sustain equilibrium and body position. Cerebral palsy (CP) is widely recognized as the prevailing motor disability observed during childhood. The term “cerebral” affects the functions, structures, or processes associated with the brain. OBJECTIVE: To compare the effects of functional training with and without dynamic cycling activity on spasticity and ambulation in children with spastic diplegia. METHODOLOGY: Sixty-two males and females having GMFCS levels II-III and Modified Ashworth Scale Grade (1, +1, and 2) with pre-diagnosed, aged 3-6 years were participated in this study. The study was conducted in Physical Therapy Department, Allied Hospital Faisalabad from February to October 2023. Group A received conventional physical therapy and functional training without dynamic cycling activity, while Group B received conventional physical therapy and functional training along with dynamic cycling activity. Spasticity and ambulation were assessed using Modified Ashworth Scale and Gross Motor Function Measure (GMFM) respectively at baseline and 12th week. Data was analyzed using SPSS version 24. RESULTS: The findings of study were originate to be significant for all the outcome variables in both groups. The results of intragroup analysis (Friedman test) and intergroup analysis (Mann- Whitney U test) obtained value is 0.001 (p< 0.05) for all variables. CONCLUSION: Conventional physical therapy and functional training along with dynamic cycling activity showed more significant results for spasticity and ambulation. KEYWORDS: Dynamic cycling, cerebral palsy, Mobility limitation.

The two-joint link model of mono- and biarticular muscles in human hindlimbs has been established on the basis of biomechanical and mechanical engineering analyses of electromyographic data and testing of the results using robotic hindlimbs equipped with mono- and/or biarticular actuators. The present review applies this model to the analysis of pedaling biomechanics and demonstrates its applicability to studies of human and non-human limb locomotion. Previously published three examples of electromyographic data on pedaling biomechanics are analyzed and reviewed in light of the two-joint link model. As comparable to published data on pedaling biomechanics, the results propose the essential parameters of the model, including activity switches and their directional changes, forces and their combined forces, all that occur in 360 degrees around the right ankle joint during the stationary and continuous pedaling activities. In addition, the co-activation of an antagonistic pair of biarticular muscles and parallel linkage function of a biarticular muscle are proposed to be tested further in both engineering and biological sciences. As biomimetics has contributed to engineering science, the models and/or hypotheses that would be generated in engineering science can be applied to biological science.

Investigations of behavior and control of voluntary stereotyped rhythmic movement contribute to the enhancement of motor function and performance of disabled, sick, injured, healthy, and exercising humans. The present article presents examples of unprompted alteration of freely chosen movement rate during voluntary stereotyped rhythmic movements. The examples, in the form of both increases and decreases of movement rate, are taken from activities of cycling, finger tapping, and locomotion. It is described that, for example, strength training, changed power output, repeated bouts, and changed locomotion speed can elicit an unprompted alteration of freely chosen movement rate. The discussion of the examples is based on a tripartite interplay between descending drive, rhythm-generating spinal neural networks, and sensory feedback, as well as terminology from dynamic systems theory. [ABSTRACT FROM AUTHOR]

Currently, many instructors of organ playing are teaching that all toe pedaling without the use of the heel is the only possible method for pedaling in the organ works of J. S. Bach. While that may be the current thinking, it is necessary to examine all of the sources available, and also to use rational thinking when deciding whether or not to use toes, heels, or a combination of them. This article will examine the issue, and when it may be preferable to use a heel depending on what the music itself is doing, and a variety of other factors. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the feasibility and acceptability of a seated pedaling device to reduce sedentary behavior (SB) in the homes of older adults. Methods: Each participant (N = 20) was outfitted with an activity monitor and seated pedaling device in the home for 7 days and randomly assigned to one of four light-intensity pedaling groups (15, 30, 45, and 60 min/day). Results: There was 100% adherence in all groups and significant group differences in the minutes pedaled per day (p <.001), with no significant difference in the total pedaling days completed (p =.241). The 15-, 30-, 45-, and 60-min groups experienced a 4.0%, 5.4%, 10.6%, and 11.3% reduction in SB on the days pedaled, respectively. Conclusion: Clinically relevant reductions in SB time were achievable in this 1-week trial. Long-term adherence and the impact of replacing SB with seated light activities on geriatric-relevant health outcomes should be investigated. [ABSTRACT FROM AUTHOR]

Background: Standard high-frequency deep brain stimulation (HF-DBS) at the subthalamic nucleus (STN) is less effective for lower-limb motor dysfunctions in Parkinson's disease (PD) patients. However, the effects of very low frequency (VLF; 4 Hz)-DBS on lower-limb movement and motor cortical oscillations have not been compared. Objective: To compare the effects of VLF-DBS and HF-DBS at the STN on a lower-limb pedaling motor task and motor cortical oscillations in patients with PD and with and without freezing of gait (FOG). Methods: Thirteen PD patients with bilateral STN-DBS performed a cue-triggered lower-limb pedaling motor task with electroencephalography (EEG) in OFF-DBS, VLF-DBS (4 Hz), and HF-DBS (120-175 Hz) states. We performed spectral analysis on the preparatory signals and compared GO-cue-triggered theta and movement-related beta oscillations over motor cortical regions across DBS conditions in PD patients and subgroups (PDFOG–and PDFOG+). Results: Both VLF-DBS and HF-DBS decreased the linear speed of the pedaling task in PD, and HF-DBS decreased speed in both PDFOG–and PDFOG+. Preparatory theta and beta activities were increased with both stimulation frequencies. Both DBS frequencies increased motor cortical theta activity during pedaling movement in PD patients, but this increase was only observed in the PDFOG + group. Beta activity was not significantly different from OFF-DBS at either frequency regardless of FOG status. Conclusion: Results suggest that VL and HF DBS may induce similar effects on lower-limb kinematics by impairing movement speed and modulating motor cortical oscillations in the lower frequency band. [ABSTRACT FROM AUTHOR]

Osteoarthritis is a disorder affecting the joints and is characterized by cellular stress and degradation of the extracellular matrix cartilage. It begins with the presence of micro- and macro-lesions that fail to repair properly, which can be initiated by multiple factors: genetic, developmental, metabolic, and traumatic. In the case of the knee, osteoarthritis affects the tissues of the diarthrodial joint, manifested by morphological, biochemical, and biomechanical modifications of the cells and the extracellular matrix. All this leads to remodeling, fissuring, ulceration, and loss of articular cartilage, as well as sclerosis of the subchondral bone with the production of osteophytes and subchondral cysts. The symptomatology appears at different time points and is accompanied by pain, deformation, disability, and varying degrees of local inflammation. Repetitive concentric movements, such as while cycling, can produce the microtrauma that leads to osteoarthritis. Aggravation of the gradual lesion in the cartilage matrix can evolve to an irreversible injury. The objective of the present review is to explain the evolution of knee osteoarthritis in cyclists, to show the scarce research performed in this particular field and extract recommendations to propose future therapeutic strategies. [ABSTRACT FROM AUTHOR]

The purpose of the current investigation was to examine the effects of exercise intensity on asymmetry in pedal forces when the accumulation of fatigue is controlled for, and to assess the reliability of asymmetry outcomes during cycling. Participants completed an incremental cycling test to determine maximal oxygen consumption and the power that elicited maximal oxygen consumption (pVO2max). Participants were allotted 30 min of recovery before then cycling at 60%, 70%, 80%, and 90% of pVO2max for 3 min each, with 5 min of active recovery between each intensity. Participants returned to the laboratory on separate days to repeat all measures. A two-way repeated measures analysis of variance (ANOVA) was utilized to detect differences in power production AI at each of the submaximal exercise intensities and between Trials 1 and 2. Intraclass correlations were utilized to assess the test–retest reliability for the power production asymmetry index (AI). An ANOVA revealed no significant intensity–visit interactions for the power production AI (f = 0.835, p = 0.485, η2 = 0.077), with no significant main effects present. ICC indicated excellent reliability in the power production AI at all intensities. Exercise intensity did not appear to affect asymmetry in pedal forces, while excellent reliability was observed in asymmetry outcomes. [ABSTRACT FROM AUTHOR]

This study focuses on developing an adaptive bicycle prototype with a manual charging mechanism for renewable energy. In response to environmental concerns and the demand for eco-friendly transportation, the research introduces a sustainable approach for short-distance travel. The goal is to demonstrate human power as an effective alternative to non-renewable energy by converting cycling’s rotational force into electrical energy. This energy is stored in a specialized battery and used to power the bicycle with an electric motor’s assistance. The methodology involves constructing and testing a prototype to capture and store energy during pedaling, analyzing mechanical components, electrical conversion, and battery efficiency. Controlled experiments assess the adaptive bicycle’s functionality and effectiveness in self-charging without external power. Results indicate successful integration of the manual charging mechanism with an average energy conversion efficiency of X%. The adaptive bicycle offers a sustainable solution for short-distance commuting, minimizing environmental impact and promoting an eco-friendly mode of travel. This innovative approach highlights the integration of renewable energy into everyday transportation, addressing environmental concerns by reducing dependence on non-renewable sources.

IntroductionAuditory-motor interactions can support the preparation for expected sensory input. We investigated the periodic modulation of beta activity in the electroencephalogram to assess the role of active auditory-motor synchronization. Pre-stimulus beta activity (13–30 Hz) has been interpreted as a neural signature of the preparation for expected sensory input.MethodsIn the current study, participants silently counted frequency deviants in sequences of pure tones either during a physically inactive control condition or while pedaling on a cycling ergometer. Tones were presented either rhythmically (at 1 Hz) or arrhythmically with variable intervals. In addition to the pedaling conditions with rhythmic (auditory-motor synchronization, AMS) or arrhythmic stimulation, a self-generated stimulus condition was used in which tones were presented in sync with the participants’ spontaneous pedaling. This condition served to explore whether sensory predictions are driven primarily by the auditory or by the motor system.ResultsPre-stimulus beta power increased for rhythmic compared to arrhythmic stimulus presentation in both sitting and pedaling conditions but was strongest in the AMS condition. Furthermore, beta power in the AMS condition correlated with motor performance, i.e., the better participants synchronized with the rhythmic stimulus sequence, the higher was pre-stimulus beta power. Additionally, beta power was increased for the self-generated stimulus condition compared with arrhythmic pedaling, but there was no difference between the self-generated and the AMS condition.DiscussionThe current data pattern indicates that pre-stimulus beta power is not limited to neuronal entrainment (i.e., periodic stimulus presentation) but represents a more general correlate of temporal anticipation. Its association with the precision of AMS supports the role of active behavior for auditory predictions.

Submaximal eccentric (ECC) cycling exercise is commonly used in research studies. No previous study has specified the required time naïve participants take to familiarize with submaximal ECC cycling. Therefore, we designed this study to determine whether critical indicators of cycling reliability and variability stabilize during 15 min of submaximal, semi-recumbent ECC cycling (ECC cycling). Twenty-two participants, aged between 18-51 years, volunteered to complete a single experimental session. Each participant completed three peak eccentric torque protocol (PETP) tests, nine countermovement jumps and 15 min of submaximal (i.e., 10% peak power output produced during the PETP tests) ECC cycling. Muscle activation patterns were recorded from six muscles (rectus femoris, RF; vastus lateralis, VL; vastus medialis, VM; soleus, SOL; medial gastrocnemius, GM; tibialis anterior, TA), during prescribed-intensity ECC cycling, using electromyography (EMG). Minute-to-minute changes in the reliability and variability of EMG patterns were examined using intra-class correlation coefficient (ICC) and variance ratios (VR). Differences between target and actual power output were also used as an indicator of familiarization. Activation patterns for 4/6 muscles (RF, VL, VM and GM) became more consistent over the session, the RF, VL and VM increasing from moderate (ICC = 0.5-0.75) to good (ICC = 0.75-0.9) reliability by the 11th minute of cycling and the GM good reliability from the 1st minute (ICC = 0.79, ICC range = 0.70-0.88). Low variability (VR ≤ 0.40) was maintained for VL, VM and GM from the 8th, 8th and 1st minutes, respectively. We also observed a significant decrease in the difference between actual and target power output (χ2 14 = 30.895, p = 0.006, W = 0.105), expressed primarily between the 2nd and 3rd minute of cycling (Z = -2.677, p = 0.007). Indicators of familiarization during ECC cycling, including deviations from target power output levels and the reliability and variability of muscle activation patterns stabilized within 15 min of cycling. Based upon this data, it would be reasonable for future studies to allocate ∼ 15 min to familiarize naïve participants with a submaximal ECC cycling protocol. [ABSTRACT FROM AUTHOR]

Abstract Background The fact that kinesio tape may be capable to enhance muscle power would qualify it as practical tool to be considered during passive warm-up (WU) or coupled with active WU processes prior to power-based performance. Therefore, the aim of this study was to investigate the single and combined effect of kinesio tape (KT) and WU on sprint cycling performance. Methods In a repeated measure design, fifteen participants underwent six sessions to assess sprint cycling performance involving a combination of three taping conditions (without KT: NoKT; with KT positioned vertically over the thigh muscles KT; with KT positioned horizontally over the thigh muscles: Sham) with two pre-exercise routines (with WU: WU; without WU: NoWU) in a randomized order. Allometric scaling of peak power (PP) and average power (AP) values were considered for each sprint. Results KT-WU demonstrated the highest PP and AP with respect to the other conditions (p 0.05). Moreover, NoKT-NoWU showed the lowest PP and AP with respect to the other conditions (p

Submaximal eccentric (ECC) cycling exercise is commonly used in research studies. No previous study has specified the required time naïve participants take to familiarize with submaximal ECC cycling. Therefore, we designed this study to determine whether critical indicators of cycling reliability and variability stabilize during 15 min of submaximal, semi-recumbent ECC cycling (ECC cycling). Twenty-two participants, aged between 18–51 years, volunteered to complete a single experimental session. Each participant completed three peak eccentric torque protocol (PETP) tests, nine countermovement jumps and 15 min of submaximal (i.e., 10% peak power output produced during the PETP tests) ECC cycling. Muscle activation patterns were recorded from six muscles (rectus femoris, RF; vastus lateralis, VL; vastus medialis, VM; soleus, SOL; medial gastrocnemius, GM; tibialis anterior, TA), during prescribed-intensity ECC cycling, using electromyography (EMG). Minute-to-minute changes in the reliability and variability of EMG patterns were examined using intra-class correlation coefficient (ICC) and variance ratios (VR). Differences between target and actual power output were also used as an indicator of familiarization. Activation patterns for 4/6 muscles (RF, VL, VM and GM) became more consistent over the session, the RF, VL and VM increasing from moderate (ICC = 0.5–0.75) to good (ICC = 0.75–0.9) reliability by the 11th minute of cycling and the GM good reliability from the 1st minute (ICC = 0.79, ICC range = 0.70–0.88). Low variability (VR ≤ 0.40) was maintained for VL, VM and GM from the 8th, 8th and 1st minutes, respectively. We also observed a significant decrease in the difference between actual and target power output (χ214 = 30.895, p = 0.006, W = 0.105), expressed primarily between the 2nd and 3rd minute of cycling (Z = -2.677, p = 0.007). Indicators of familiarization during ECC cycling, including deviations from target power output levels and the reliability and variability of muscle activation patterns stabilized within 15 min of cycling. Based upon this data, it would be reasonable for future studies to allocate ∼ 15 min to familiarize naïve participants with a submaximal ECC cycling protocol.

The purpose of the current investigation was to examine the effects of exercise intensity on asymmetry in pedal forces when the accumulation of fatigue is controlled for, and to assess the reliability of asymmetry outcomes during cycling. Participants completed an incremental cycling test to determine maximal oxygen consumption and the power that elicited maximal oxygen consumption (pVO2max). Participants were allotted 30 min of recovery before then cycling at 60%, 70%, 80%, and 90% of pVO2max for 3 min each, with 5 min of active recovery between each intensity. Participants returned to the laboratory on separate days to repeat all measures. A two-way repeated measures analysis of variance (ANOVA) was utilized to detect differences in power production AI at each of the submaximal exercise intensities and between Trials 1 and 2. Intraclass correlations were utilized to assess the test–retest reliability for the power production asymmetry index (AI). An ANOVA revealed no significant intensity–visit interactions for the power production AI (f = 0.835, p = 0.485, η2 = 0.077), with no significant main effects present. ICC indicated excellent reliability in the power production AI at all intensities. Exercise intensity did not appear to affect asymmetry in pedal forces, while excellent reliability was observed in asymmetry outcomes.

Background: One-legged pedaling is of interest to elite cyclists and clinicians. However, muscular usage in 1-legged vs. 2-legged pedaling is not fully understood. Thus, the study was aimed to examine changes in leg muscle activation patterns between 2-legged and 1-legged pedaling. Methods: Fifteen healthy young recreational cyclists performed both 1-legged and 2-legged pedaling trials at about 30 Watt per leg. Surface electromyography electrodes were placed on 10 major muscles of the left leg. Linear envelope electromyography data were integrated to quantify muscle activities for each crank cycle quadrant to evaluate muscle activation changes. Results: Overall, the prescribed constant power requirements led to reduced downstroke crank torque and extension-related muscle activities (vastus lateralis, vastus medialis, and soleus) in 1-legged pedaling. Flexion-related muscle activities (biceps femoris long head, semitendinosus, lateral gastrocnemius, medial gastrocnemius, tensor fasciae latae, and tibialis anterior) in the upstroke phase increased to compensate for the absence of contralateral leg crank torque. During the upstroke, simultaneous increases were seen in the hamstrings and uni-articular knee extensors, and in the ankle plantarflexors and dorsiflexors. At the top of the crank cycle, greater hip flexor activity stabilized the pelvis. Conclusion: The observed changes in muscle activities are due to a variety of changes in mechanical aspects of the pedaling motion when pedaling with only 1 leg, including altered crank torque patterns without the contralateral leg, reduced pelvis stability, and increased knee and ankle stiffness during the upstroke.

We investigated the relationship between attentional resources and pedaling cadence using electroencephalography (EEG) to measure P300 amplitudes and latencies. Twenty-five healthy volunteers performed the oddball task while pedaling on a stationary bike or relaxing (i.e., no pedaling). We set them four conditions, namely, (1) performing only the oddball task (i.e., control), (2) performing the oddball task while pedaling at optimal cadence (i.e., optimal), (3) performing the oddball task while pedaling faster than optimal cadence (i.e., fast), and (4) performing the oddball task while pedaling slower than optimal cadence (i.e., slow). P300 amplitudes at Cz and Pz electrodes under optimal, fast, and slow conditions were significantly lower than those under control conditions. P300 amplitudes at Pz under fast and slow conditions were significantly lower than those under the optimal condition. No significant changes in P300 latency at any electrode were observed under any condition. Our findings revealed that pedaling at non-optimal cadence results in less attention being paid to external stimuli compared with pedaling at optimal cadence. [ABSTRACT FROM AUTHOR]

The present study aimed to examine the profile of energy metabolism during repetition sprint exercises with different rest durations. Nine competitive male track and field athletes performed a submaximal-intensity increment exercise and 4 kinds of 2 consecutive 30-s sprints tests with rest durations of 4, 10, 15, and 20 min, respectively. The mean power output during these sprints was evaluated as the average value over the entire 30-s period. Aerobic and anaerobic energy during these sprints was determined from the extrapolated linear regression between power and the steady-state O2 uptake obtained during the submaximal-intensity increment exercise. During 2nd sprints compared with 1st sprints in the respective tests, the mean power output decreased significantly in the tests with rest durations of 4, 10, and 15 min; in all the tests, the aerobic energy increased significantly and the anaerobic energy decreased significantly. These results suggest that the 1st sprint in a repetition sprint exercise causes activation of aerobic metabolism and inhibition of anaerobic metabolism during the 2nd sprint. On the other hand, it is also suggested that recovery of anaerobic metabolism after the 1st sprint requires a longer rest duration than that for recovery of performance in the repetition sprint exercise. [ABSTRACT FROM AUTHOR]

We investigated the relationship between attentional resources and pedaling cadence using electroencephalography (EEG) to measure P300 amplitudes and latencies. Twenty-five healthy volunteers performed the oddball task while pedaling on a stationary bike or relaxing (i.e., no pedaling). We set them four conditions, namely, (1) performing only the oddball task (i.e., control), (2) performing the oddball task while pedaling at optimal cadence (i.e., optimal), (3) performing the oddball task while pedaling faster than optimal cadence (i.e., fast), and (4) performing the oddball task while pedaling slower than optimal cadence (i.e., slow). P300 amplitudes at Cz and Pz electrodes under optimal, fast, and slow conditions were significantly lower than those under control conditions. P300 amplitudes at Pz under fast and slow conditions were significantly lower than those under the optimal condition. No significant changes in P300 latency at any electrode were observed under any condition. Our findings revealed that pedaling at non-optimal cadence results in less attention being paid to external stimuli compared with pedaling at optimal cadence.

Background: The fact that kinesio tape may be capable to enhance muscle power would qualify it as practical tool to be considered during passive warm-up (WU) or coupled with active WU processes prior to power-based performance. Therefore, the aim of this study was to investigate the single and combined effect of kinesio tape (KT) and WU on sprint cycling performance. Methods: In a repeated measure design, fifteen participants underwent six sessions to assess sprint cycling performance involving a combination of three taping conditions (without KT: NoKT; with KT positioned vertically over the thigh muscles KT; with KT positioned horizontally over the thigh muscles: Sham) with two pre-exercise routines (with WU: WU; without WU: NoWU) in a randomized order. Allometric scaling of peak power (PP) and average power (AP) values were considered for each sprint. Results: KT-WU demonstrated the highest PP and AP with respect to the other conditions (p < 0.05), except for AP that was similar to Sham-WU (p > 0.05). Moreover, NoKT-NoWU showed the lowest PP and AP with respect to the other conditions (p < 0.05). Conclusions: Overall, our findings suggest that kinesio tape might be a possible tool to be combined with an active WU routine, inducing benefit on sprint performance. Moreover, KT may be considered a potential strategy to include within a passive WU, perhaps where an active WU is not feasible. However, as the influence of KT on muscle function is still unclear, our results should not be overinterpreted. [ABSTRACT FROM AUTHOR]

Abstract Background Neuromuscular electrical stimulation (NMES) is extensively used in stroke motor rehabilitation. How it promotes motor recovery remains only partially understood. NMES could change muscular properties, produce altered sensory inputs, and modulate fluctuations of cortical activities; but the potential contribution from cortico-muscular couplings during NMES synchronized with dynamic movement has rarely been discussed. Method We investigated cortico-muscular interactions during passive, active, and NMES rhythmic pedaling in healthy subjects and chronic stroke survivors. EEG (128 channels), EMG (4 unilateral lower limb muscles) and movement parameters were measured during 3 sessions of constant-speed pedaling. Sensory-level NMES (20 mA) was applied to the muscles, and cyclic stimulation patterns were synchronized with the EMG during pedaling cycles. Adaptive mixture independent component analysis was utilized to determine the movement-related electro-cortical sources and the source dipole clusters. A directed cortico-muscular coupling analysis was conducted between representative source clusters and the EMGs using generalized partial directed coherence (GPDC). The bidirectional GPDC was compared across muscles and pedaling sessions for post-stroke and healthy subjects. Results Directed cortico-muscular coupling of NMES cycling was more similar to that of active pedaling than to that of passive pedaling for the tested muscles. For healthy subjects, sensory-level NMES could modulate GPDC of both ascending and descending pathways. Whereas for stroke survivors, NMES could modulate GPDC of only the ascending pathways. Conclusions By clarifying how NMES influences neuromuscular control during pedaling in healthy and post-stroke subjects, our results indicate the potential limitation of sensory-level NMES in promoting sensorimotor recovery in chronic stroke survivors.

Bicycles with electrically powered pedal assistance (PA) show great potential as ecological alternatives for engine-based vehicles. There is plenty of research available about the influence of various bicycle parameters on cycling technique. Though, to the best of the authors' knowledge, there is none about the influence of PA. In this study, a recreational bicycle is equipped with PA and unique instrumentation to measure the user-induced loads on seat, steer and pedals. Joint loading is derived in the sagittal plane from inverse dynamics and muscle activity of the lower limbs is recorded with an electromyography system integrated in cycling pants. An experiment is set up, in which volunteers cycle on an athletics track, with a varying level of PA and a varying seat height. An ANOVA is conducted to determine significant differences due to the level of PA and seat height and to analyze the interaction effect. No interaction effect was found and only differences due to the level of PA were significant. Knowledge about the influence of PA provides insights into (i) electric bicycle design; (ii) the usage of electric bicycle for physically challenged people; (iii) the usage of electric bicycles as a rehabilitation tool. [ABSTRACT FROM AUTHOR]

• Two-legged pedaling crank torque pattern altered when pedaling with 1 leg only. • Reduced downstroke crank torque led to reduced extension-related leg muscle activities. • Greater flexion-related muscle activities explained larger upstroke crank torque. • In the upstroke, 1-legged pedaling would require greater joint stiffness. • At the top of the crank cycle, greater hip flexor activity would stabilize the pelvis. One-legged pedaling is of interest to elite cyclists and clinicians. However, muscular usage in 1-legged vs. 2-legged pedaling is not fully understood. Thus, the study was aimed to examine changes in leg muscle activation patterns between 2-legged and 1-legged pedaling. Fifteen healthy young recreational cyclists performed both 1-legged and 2-legged pedaling trials at about 30 Watt per leg. Surface electromyography electrodes were placed on 10 major muscles of the left leg. Linear envelope electromyography data were integrated to quantify muscle activities for each crank cycle quadrant to evaluate muscle activation changes. Overall, the prescribed constant power requirements led to reduced downstroke crank torque and extension-related muscle activities (vastus lateralis, vastus medialis, and soleus) in 1-legged pedaling. Flexion-related muscle activities (biceps femoris long head, semitendinosus, lateral gastrocnemius, medial gastrocnemius, tensor fasciae latae, and tibialis anterior) in the upstroke phase increased to compensate for the absence of contralateral leg crank torque. During the upstroke, simultaneous increases were seen in the hamstrings and uni-articular knee extensors, and in the ankle plantarflexors and dorsiflexors. At the top of the crank cycle, greater hip flexor activity stabilized the pelvis. The observed changes in muscle activities are due to a variety of changes in mechanical aspects of the pedaling motion when pedaling with only 1 leg, including altered crank torque patterns without the contralateral leg, reduced pelvis stability, and increased knee and ankle stiffness during the upstroke. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The hypothesis of modular control, which stands on the existence of muscle synergies as building blocks of muscle coordination, has been investigated in a great variety of motor tasks and species. Yet, its role during learning processes is still largely unexplored. To what extent is such modular control flexible, in terms of spatial structure and temporal activation, to externally or internally induced adaptations, is a debated issue. To address this question, we designed a biofeedback experiment to induce changes in the timing of muscle activations during leg cycling movements. The protocol consisted in delaying the peak of activation of one target muscle and using its electromyography (EMG) envelope as visual biofeedback. For each of the 10 healthy participants, the protocol was repeated for three different target muscles: Tibialis Anterioris (TA), Gastrocnemius Medialis (GM), and Vastus Lateralis (VL). To explore the effects of the conditioning protocol, we analyzed changes in the activity of eight lower limb muscles by applying different models of modular motor control [i.e., fixed spatial components (FSC) and fixed temporal components (FTC)]. Our results confirm the hypothesis that visual EMG biofeedback is able to induce changes in muscle coordination. Subjects were able to shift the peak of activation of the target muscle, with a delay of (49 ± 27°) across subjects and conditions. This time shift generated a reorganization of all the other muscles in terms of timing and amplitude. By using different models of modular motor control, we demonstrated that neither spatially invariant nor temporally invariant muscle synergies alone were able to account for these changes in muscle coordination after learning, while temporally invariant muscle synergies with adjustments in timing could capture most of muscle activity adaptations observed after the conditioning protocol. These results suggest that short-term learning in rhythmic tasks is built upon synergistic temporal commands that are robust to changes in the task demands.

A low-cost Brain-Machine Interface (BMI) based on electroencephalography for lower-limb motor recovery of post-stroke patients is proposed here, which provides passive pedaling as feedback, when patients trigger a Mini-Motorized Exercise Bike (MMEB) by executing pedaling motor imagery (MI). This system was validated in an On-line phase by eight healthy subjects and two post-stroke patients, which felt a closed-loop commanding the MMEB due to the fast response of our BMI. It was developed using methods of low-computational cost, such as Riemannian geometry for feature extraction, Pair-Wise Feature Proximity (PWFP) for feature selection, and Linear Discriminant Analysis (LDA) for pedaling imagery recognition. The On-line phase was composed of two sessions, where each participant completed a total of 12 trials per session executing pedaling MI for triggering the MMEB. As a result, the MMEB was successfully triggered by healthy subjects for almost all trials (ACC up to 100%), while the two post-stroke patients, PS1 and PS2, achieved their best performance (ACC of 41.67% and 91.67%, respectively) in Session #2. These patients improved their latency (2.03 ± 0.42 s and 1.99 ± 0.35 s, respectively) when triggering the MMEB, and their performance suggests the hypothesis that our system may be used with chronic stroke patients for lower-limb recovery, providing neural relearning and enhancing neuroplasticity. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Purpose: A key determinant of muscle coordination and maximum power output during cycling is pedaling cadence. During cycling, the neuromuscular system may select from numerous solutions that solve the task demands while producing the same result. For more challenging tasks, fewer solutions will be available. Changes in the variability of individual muscle excitations (EMG) and multimuscle coordination, quantified by entropic half-life (EnHL), can reflect the number of solutions available at each system level. We, therefore, ask whether reduced variability in muscle coordination patterns occur at critical cadences and if they coincide with reduced variability in excitations of individual muscles. Methods: Eleven trained cyclists completed an array of cadence–power output conditions. The EnHL of EMG intensity recorded from 10 leg muscles and EnHL of principal components describing muscle coordination were calculated. Multivariate adaptive regressive splines were used to determine the relationships between each EnHL and cycling condition or excitation characteristics (duration, duty cycle). Results: Muscle coordination became more persistent at cadences up to 120 rpm, indicated by increasing EnHL values. Changes in EnHL at the level of the individual muscles differed from the changes in muscle coordination EnHL, with longer EnHL occurring at the slowest (<80 rpm) and fastest (>120 rpm) cadences. The EnHL of the main power producing muscles, however, reached a minimum by 80 rpm and did not change across the faster cadences studied. Conclusions: Muscle coordination patterns, rather than the contribution of individual muscles, are key to power production at faster cadences in trained cyclists. Reductions in maximum power output at cadences above 120 rpm could be a function of the time available to coordinate orientation and transfer of forces to the pedals. [ABSTRACT FROM AUTHOR]

Central nervous system (CNS) uses the combination of a small number of motor primitives, named muscle synergies, for simplification of motor control in human movement. The aim of this study was to investigate the muscle coordination in both leg muscles during pedaling by time-varying muscle synergy extraction. Twenty healthy subjects performed three 6-min cycling tasks over a range of rotational speed (40, 50, and 60 rpm) and resistant torque (3, 5, and 7 N/M). Surface electromyography signals were recorded during pedaling from eight muscles of the right and left lower limbs. We extracted four time-varying muscle synergies from sEMG patterns. Mean and standard deviation of the quality of the signal reconstruction (R2) for all subjects was obtained 0.9328 ± 0.0120. We investigated the similarity of muscle synergies during cycling across various mechanical conditions. We found the high degrees of similarity (>0.85) among the sets of time-varying muscle synergies across mechanical conditions and also across subjects. Our results show that the same motor control strategies for cycling are used by all subjects in various mechanical conditions. [ABSTRACT FROM AUTHOR]

Cadence choice during cycling has been of considerable interest among cyclists, coaches, and researchers for nearly 100 years. The present review examines and summarizes the current knowledge of factors affecting the freely chosen cadence during submaximal cycling and of the influence of cadence choice on performance. In addition, suggestions for future research are given along with scientifically based, practical recommendations for those involved in cycling. Within the past 10 years, a number of papers have been published that have brought novel insight into the subject. For example, under the influence of spinal central pattern generators, a robust innate voluntary motor rhythm has been suggested as the primary basis for freely chosen cadence in cycling. This might clarify the cadence paradox in which the freely chosen cadence during low-to-moderate submaximal cycling is considerably higher and thereby less economical than the energetically optimal cadence. A number of factors, including age, power output, and road gradient, have been shown to affect the choice of cadence to some extent. During high-intensity cycling, close to the maximal aerobic power output, cyclists choose an energetically economical cadence that is also favorable for performance. In contrast, the choice of a relatively high cadence during cycling at low-to-moderate intensity is uneconomical and could compromise performance during prolonged cycling. [ABSTRACT FROM AUTHOR]

The purpose of the current investigation was to examine the effects of exercise intensity and a participant’s cycling experience on asymmetry in pedal forces during cycling. Participants were classified as cycling experienced (CE) or non-cycling experienced (NCE) based on self-reported training history. Participants completed an incremental cycling test via a cycle ergometer with inspired and expired gases, capillary blood lactate and pedaling forces collected throughout the test. Group X exercise intensity comparisons were analyzed at workloads corresponding to 2 mmol/L and 4 mmol/L for the blood lactate accumulation and peak power output, respectively. No Group X exercise intensity interactions for any variables (p > 0.05) were observed. The main effect on the exercise intensity was observed for absolute (p = 0.000, η2 = 0.836) and relative (p = 0.000, η2 = 0.752) power outputs and pedal force effectiveness (PFE) (p = 0.000, η2 = 0.728). The main effect for the group was observed for absolute (p = 0.007, η2 = 0.326) and relative (p = 0.001, η2 = 0.433) power outputs, the absolute difference between the lower limbs in power production (p = 0.047, η2 = 0.191), the peak crank torque asymmetry index (p = 0.031, η2 = 0.222) and the PFE (p = 0.014, η2 = 0.280). The exercise intensity was observed to have no impact on asymmetry in pedaling forces during cycling.

Purpose: to study special aspects of pedaling structure and create diagnostic models of cyclists movements’ coordination structure under fatigue in differently oriented trainings. Material: in the research 18 elite sportsmen participated. Sportsmen fulfilled training programs on ergo-meter, directed on development of speed-power potentials and endurance in anaerobic and aerobic work. Results: it was found that in period of fatigue overcoming dynamic shocks in applied efforts disappear and the picture of bio-dynamic components becomes smoother. With it, relative usage of efforts’ horizontal components increases. In period of evident fatigue variability of movements’ kinematic characteristics and integrated bio-electrical activity of the tested muscles increase; cyclists’ efficiency reduces. Conclusions: distinctions in movements’ structure of cyclists in period of fatigue overcoming witness about certain tendency to transition from impulse-type pedaling to circular type. It pre-conditioned increase importance efforts’ components and effectiveness of their usage.

ObjectiveEccentric (ECC) cycle-ergometers have recently become commercially-available, offering a novel method for rehabilitation training. Many studies have reported that ECC cycling enables the development of higher levels of muscular force at lower cardiorespiratory and metabolic loads, leading to greater force enhancements after a training period. However, fewer studies have focused on the specific perceptual and neuromuscular changes. As the two latter aspects are of major interest in clinical settings, this review aimed to present an overview of the current literature centered on the neuromuscular and perceptual responses to submaximal ECC cycling in comparison to concentric (CON) cycling.DesignNarrative review of the literature.ResultsAt a given mechanical workload, muscle activation is lower in ECC than in CON while the characteristics of the musculo-articular system (i.e., muscle-tendon unit, fascicle, and tendinous tissue length) are quite similar. At a given heart rate or oxygen consumption, ECC cycling training results in greater muscular hypertrophy and strength gains than CON cycling. On the contrary, CON cycling training seems to enhance more markers of muscle aerobic metabolism than ECC cycling performed at the same heart rate intensity. Data concerning perceptual responses, and neuromuscular mechanisms leading to a lower muscle activation (i.e., neural commands from cortex to muscular system) at a given mechanical workload are scarce.ConclusionEven though ECC cycling appears to be a very useful tool for rehabilitation purposes the perceptual and neural commands from cortex to muscular system during exercise need to be further studied.

Sprint cycling performance is heavily dependent on mechanical peak power output (PPO) and the underlying power- and torque-cadence relationships. Other key indices of these relationships include maximum torque (TMAX), cadence (CMAX) and optimal cadence (COPT). Two common methods are used in the laboratory to ascertain PPO: isovelocity and isoinertial. Little research has been carried out to compare the magnitude and reliability of these performance measures with these two common sprint cycling assessments. The aim of this study was to compare the magnitude and reliability of PPO, TMAX , CMAX and COPT measured with isovelocity and isoinertial sprint cycling methods. Two experimental sessions required 20 trained cyclists to perform isoinertial sprints and then isovelocity sprints. For each method, power-cadence and torque-cadence relationships were established, and PPO and COPT were interpolated and TMAX and CMAX were extrapolated. The isoinertial method produced significantly higher PPO (p<0.001) and TMAX (p<0.001) than the isovelocity method. However, the isovelocity method produced significantly higher COPT (p<0.001) and CMAX (p=0.002). Both sprint cycling tests showed high levels of between-session reliability (isoinertial 2.9–4.4%; isovelocity 2.7–4.0%). Functional measures of isovelocity and isoinertial sprint cycling tests were highly reliable but should not be used interchangably. [ABSTRACT FROM AUTHOR]

Although it is known that the muscle activation patterns used to produce even simple movements can vary between individuals, these differences have not been considered to prove the existence of individual muscle activation strategies (or signatures). We used a machine learning approach (support vector machine) to test the hypothesis that each individual has unique muscle activation signatures. Eighty participants performed a series of pedaling and gait tasks, and 53 of these participants performed a second experimental session on a subsequent day. Myoelectrical activity was measured from eight muscles: vastus lateralis and medialis, rectus femoris, gastrocnemius lateralis and medialis, soleus, tibialis anterior, and biceps femoris-long head. The classification task involved separating data into training and testing sets. For the within-day classification, each pedaling/gait cycle was tested using the classifier, which had been trained on the remaining cycles. For the between-day classification, each cycle from day 2 was tested using the classifier, which had been trained on the cycles from day 1. When considering all eight muscles, the activation profiles were assigned to the corresponding individuals with a classification rate of up to 99.28% (2,353/2,370 cycles) and 91.22% (1,341/1,470 cycles) for the withinday and between-day classification, respectively. When considering the within-day classification, a combination of two muscles was sufficient to obtain a classification rate _80% for both pedaling and gait. When considering between-day classification, a combination of four to five muscles was sufficient to obtain a classification rate _80% for pedaling and gait. These results demonstrate that strategies not only vary between individuals, as is often assumed, but are unique to each individual. NEW & NOTEWORTHY We used a machine learning approach to test the uniqueness and robustness of muscle activation patterns. We considered that, if an algorithm can accurately identify participants, one can conclude that these participants exhibit discernible differences and thus have unique muscle activation signatures. Our results show that activation patterns not only vary between individuals, but are unique to each individual. Individual differences should, therefore, be considered relevant information for addressing fundamental questions about the control of movement. [ABSTRACT FROM AUTHOR]

We have previously shown that supraspinal excitability is higher during arm cycling than a position- and intensity-matched tonic contraction. The present study sought to determine if short-interval intracortical inhibition (SICI) was present during arm cycling and if so, if the amount of SICI was different from an intensity-matched tonic contraction. SICI was assessed using conditioning stimuli (CS) of 70 and 90% of active motor threshold (AMT) and a test stimulus (TS) of 120% AMT at an interstimulus interval (ISI) of 2.5 ms. SICI was elicited in all participants; on average (i.e., cycling and tonic contraction grouped) test MEP amplitudes were reduced by 64.2% (p < 0.001) and 62.8% (p = 0.001) following conditioning stimuli of 70% and 90% AMT, respectively. There was no significant difference in extent of SICI between tasks (p = 0.360). These data represent the novel finding that SICI is present during arm cycling, a motor output partially mediated by spinal interneuronal networks. The amount of SICI, however, was not different from that during a position- and intensity-matched tonic contraction, suggesting that SICI is not likely a cortical mechanism contributing to higher supraspinal excitability during arm cycling compared to tonic contraction. [ABSTRACT FROM AUTHOR]

The paper dwells upon the study of pedaling types in highly skilled track cyclists. The study involved 18 skilled cyclists. Kinematic, dynamic and integral indices of pedaling technique were examined. The studies revealed three types of pedaling according to the character of effort distribution. The first type is characterized by cyclist using the increased values of efforts of the vertical components of both legs at the distance. The second type includes pedaling technique variants that are based upon different degree of exceeding the values of mean group model characteristics of motion structure at the distance in terms of the efforts of all zones of right or left foot pedaling. The third type of motion structure is distinguished by high values of efforts of right foot pushing through and pushing down and left foot following through and pulling up, or vice versa - left foot pushing through and pushing down and right foot following through and pulling up. Pedaling technique is recommended to improve depending on its type. Moreover, one should pay attention at the development of the "leading" zones of pedaling cycle rather than the "lagging" ones. [ABSTRACT FROM AUTHOR]

Short-term delayed effects of Kinesio taping on sprint cycling performance. J Strength Cond Res 33(5): 1232-1236, 2019—The aim of this study was to assess short-term delayed effects of Kinesio taping (KT) on maximal cycling performance. A design with repeated measures was used. Fifteen healthy trained subjects underwent 3 conditions: no KT (without tape), KT (Kinesio tape applied longitudinally on the thighs), and sham taping (Kinesio tape applied horizontally on the thighs). Each subject performed 2 sets of 3 x 6-second sprints (separated by 3 minutes) interspersed by 30 minutes of rest on a cycle ergometer. Allometric scaling of peak power (PP) and average power (AP) values were computed and analyzed for each sprint performance. Both PP and AP decreased significantly after 30 minutes (between set 1 and set 2) in all conditions, with a greater decrease in no KT condition compared with KT and sham (p < 0.01). No significant differences were observed between KT and sham conditions. The application of KT on thigh muscles attenuated the performance decrease that occurred after 30 minutes of rest between the 2 sets compared with the no KT condition. This finding suggests athletes may use KT to better manage their performance during delays in competition events. [ABSTRACT FROM AUTHOR]

Objective: Eccentric (ECC) cycle-ergometers have recently become commercially-available, offering a novel method for rehabilitation training. Many studies have reported that ECC cycling enables the development of higher levels of muscular force at lower cardiorespiratory and metabolic loads, leading to greater force enhancements after a training period. However, fewer studies have focused on the specific perceptual and neuromuscular changes. As the two latter aspects are of major interest in clinical settings, this review aimed to present an overview of the current literature centered on the neuromuscular and perceptual responses to submaximal ECC cycling in comparison to concentric (CON) cycling. Design: Narrative review of the literature. Results: At a given mechanical workload, muscle activation is lower in ECC than in CON while the characteristics of the musculo-articular system (i.e., muscle-tendon unit, fascicle, and tendinous tissue length) are quite similar. At a given heart rate or oxygen consumption, ECC cycling training results in greater muscular hypertrophy and strength gains than CON cycling. On the contrary, CON cycling training seems to enhance more markers of muscle aerobic metabolism than ECC cycling performed at the same heart rate intensity. Data concerning perceptual responses, and neuromuscular mechanisms leading to a lower muscle activation (i.e., neural commands from cortex to muscular system) at a given mechanical workload are scarce. Conclusion: Even though ECC cycling appears to be a very useful tool for rehabilitation purposes the perceptual and neural commands from cortex to muscular system during exercise need to be further studied. [ABSTRACT FROM AUTHOR]