Lower-Limb Muscle Contractile Properties, Explosive Power and the Subjective Response of Elite Soccer Players to the COVID-19 Lockdown

The present study examined the effects of the lockdown period on basic anthropometric measures, countermovement jumping performance, skeletal muscle contractile properties derived from tensiomyography (TMG), injury incidence, and self-assessed general well-being in elite soccer players. A total of 266 players were assessed before (PRE) and 32 players were reassessed 11 days after (POST) the COVID-19 period. Significant changes in the TMG parameters were observed POST compared to PRE: contraction time (Tc) increased from 6% to 50% in vastus lateralis [VL] (p = 0.009) and biceps femoris [BF] (p < 0.001), respectively; whereas radial displacement (Dm) increased for 19% in BF (p = 0.036) and 17% in VL (p < 0.001), respectively. Jumping performance remained unchanged from PRE to POST In addition, athletes rated the lockdown period as a positive event and felt psychologically better during the lockdown, primarily because they spent more time with family members and friends. Although there were no differences in any of the variables describing lower limb muscle power following the two-month lockdown, the altered contractile properties of the assessed muscles suggest suboptimal conditioning of the football players.

A novel methodology for the synchronous collection and multimodal visualisation of continuous neurocardiovascular and neuromuscular physiological data in adults with long COVID

Reports suggest that adults with post-COVID-19 syndrome or long COVID may be affected by orthostatic intolerance syndromes, with autonomic nervous system dysfunction as a possible causal factor of neurocardiovascular instability (NCVI). Long COVID can also manifest as prolonged fatigue, which may be linked to neuromuscular function impairment (NMFI). The current clinical assessment for NCVI monitors neurocardiovascular performance upon the application of orthostatic stressors such as an active (i.e. self-induced) stand or a passive (tilt table) standing test. Lower limb muscle contractions may be important in orthostatic recovery via the skeletal muscle pump. In this study, adults with long COVID were assessed with a protocol that, in addition to the standard NCVI tests, incorporated simultaneous lower limb muscle monitoring for NMFI assessment. To accomplish such an investigation, a wide range of continuous non-invasive biomedical technologies were employed, including digital artery photoplethysmography for the extraction of cardiovascular signals, near-infrared spectroscopy for the extraction of regional tissue oxygenation in brain and muscle, and electromyography for assessment of timed muscle contractions in the lower limbs. With the novel technique described and exemplified in this paper, we were able to integrate signals from all instruments used in the assessment in a precisely synchronized fashion. We demonstrate that it is possible to visualize the interactions between all different physiological signals during the combined NCVI/NMFI assessment. Multiple counts of evidence were collected, which can capture the dynamics between skeletal muscle contractions and neurocardiovascular responses. The proposed multimodal data visualization can offer an overview of the functioning of the muscle pump during both supine rest and orthostatic recovery and can conduct comparison studies with signals from multiple participants at any given time in the assessment. This could help researchers and clinicians generate and test hypotheses based on the multimodal inspection of raw data, in long COVID and other clinical cohorts.

Grey Relational Analysis of Lower Limb Muscle Fatigue and Pedalling Performance Decline of Elite Athletes during a 30-Second All-Out Sprint Cycling Exercise

The 30-second all-out sprint cycling exercise is a classical sport capacity evaluation method, which may cause severe lower limb muscle fatigue. However, the relationship between lower limb muscle fatigue and the decline in exercise performance during 30-second sprint cycling remains unclear. In this study, ten cyclists volunteered to participate in a 30-second all-out sprint cycling while power, cadence, and surface electromyographic (EMG) signals of eight lower limb muscles were recorded during the exercise. EMG mean frequency (MNF) of each lower limb muscle group was computed for every 3-second epoch based on wavelet packet transformation. Grey relational grades between pedalling performance and the EMG MNF of each lower limb muscle group during the whole process were calculated. The results demonstrated that EMG MNF of the rectus femoris (RF), vastus (VAS), gastrocnemius (GAS), and tibialis anterior (TA) progressively tired during a 30-second all-out sprint cycling exercise. Of the muscles evaluated, the degree of fatigue of TA showed the greatest association with exercise performance decline, whereas the muscle fatigue of RF, VAS, and GAS also significantly impacted exercise performance during a 30-second all-out sprint cycling exercise.

The Effect of Lower-Limb Exercise on Pain Management of the Patients Undergoing Posterior Lumbar Fusion Surgery: A Retrospective Case-Control Study

Purpose. The purpose of this study is to investigate the clinical effect of lower-limb exercise, when combined with celecoxib, on pain management of patients undergoing posterior lumbar fusion surgeries. Methods. The patients undergoing posterior lumbar fusion surgeries between 01/2018 and 06/2021 were retrospectively identified, with their data collected. After surgery, some patients took celecoxib for analgesia (celecoxib group, 200 mg/day) while the others took celecoxib together with lower-limb exercise (combined group, celecoxib-200 mg/day). On postoperative days (POD) 1, 3, 7, and 14, data were collected and analyzed regarding the following items: patient satisfaction, lower-limb muscle force, lumbar JOA score (29 points), Oswestry Disability Index (ODI), and visual analog scale (VAS) score. Results. A total of 225 participants were included in this study. Specifically, 120 cases were admitted into in the celecoxib group and 105 were included in the combined group. Comparisons of baseline data did not indicate any difference between the combined group and the celecoxib group. Data analysis showed that patient satisfaction in the combined group was significantly higher than the celecoxib group on POD 3, 7, and 14, respectively (all p < 0.001 ). Moreover, the combined group had less VAS score compared with the celecoxib group on POD 3, 7, and 14, respectively (all p < 0.01 ). In addition, lower-limb muscle force in the combined group was significantly stronger than that in the celecoxib group on POD 3 and POD 7, respectively (both p < 0.01 ). Furthermore, the combined group achieved less ODI score than the celecoxib group on POD 3, 7, and 14, respectively (all p < 0.05 ). Comparisons of the lumbar JOA score did not suggest any statistical difference during the whole follow-up period. Conclusions. In conclusion, postoperative lower-limb rehabilitation exercise can help to release pain after lumbar fusion surgeries. Additionally, postoperative lower-limb exercise can facilitate the recovery of lower-limb muscle force, as well as improving patient satisfaction.

A Semi-recumbent Eccentric Cycle Ergometer Instrumented to Isolate Lower Limb Muscle Contractions to the Appropriate Phase of the Pedal Cycle

Eccentric (ECC) cycling is used in rehabilitation and sports conditioning settings. We present the construction and mode of operation of a custom-built semi-recumbent ECC cycle designed to limit the production of lower limb muscle activity to the phase of the pedal cycle known to produce ECC contractions. A commercially available semi-recumbent frame and seat (Monarch, 837E Semi-recumbent Bike, Sweden) were used to assemble the ergometer. An electrical drive train system was constructed using individual direct drive servo motors. To avoid active muscle activation occurring during the non-ECC pedaling phase of cycling, a “trip” mechanism was integrated into the drivetrain system using a servo-driven regenerative braking mechanism based on the monitoring of the voltage produced over and above a predetermined threshold produced by the motors. The servo drive internal (DC bus) voltage is recorded and internally monitored during opposing (OPP) and non-opposing (N-OPP) phases of the pedal cycle. To demonstrate that the cycle functions as desired and stops or “trips” when it is supposed to, we present average (of 5 trials) muscle activation patterns of the principal lower limb muscles for regular ECC pedal cycles in comparison with one pedal cycle during which the muscles activated outside the desired phase of the cycle for a sample participant. This semi-recumbent ECC cycle ergometer has the capacity to limit the occurrence of muscle contraction only to the ECC phase of cycling. It can be used to target that mode of muscle contraction more precisely in rehabilitation or training studies.

Can Corticomuscular Coherence Differentiate between REM Sleep Behavior Disorder with or without Parkinsonism?

REM sleep behavior disorder (RBD) could be a predictor of Parkinsonism even before development of typical motor symptoms. This study aims to characterize clinical features and corticomuscular and corticocortical coherence (CMC and CCC, respectively) during sleep in RBD patients with or without Parkinsonism. We enrolled a total of 105 subjects, including 20 controls, 54 iRBD, and 31 RBD+P patients, patients who were diagnosed as idiopathic RBD (iRBD) and RBD with Parkinsonism (RBD+P) in our neurology department. We analyzed muscle atonia index (MAI) and CMC between EEG and chin/limb muscle electromyography (EMG) and CCC during different sleep stages. Although differences in the CMC of iRBD group were observed only during REM sleep, MAI differences between groups were noted during both REM and NREM N2 stage sleep. During REM sleep, CMC was higher and MAI was reduced in iRBD patients compared to controls (p = 0.001, p < 0.001, respectively). Interestingly, MAI was more reduced in RBD+P compared to iRBD patients. In comparison, CCC was higher in iRBD patients compared to controls whereas CCC was lower in RBD+P groups compared to control and iRBD groups in various frequency bands during both NREM N2 and REM sleep stages. Among them, increased CMC during REM sleep revealed correlation between clinical severities of RBD symptoms. Our findings indicate that MAI, CMC, and CCC showed distinctive features in iRBD and RBD+P patients compared to controls, suggesting potential usefulness to understand possible links between these diseases.

Upper Limb Isokinetic Muscle Strength Predicts the Performance in Cross-Country Sit-Skiing

Understanding the physical fitness attributes in a sport-specific technical skill is a key to improve the action economy, and thus aerobic endurance performance. The present study was designed to investigate how upper limb muscle strength predicts double poling (DP) power performance in cross-country sit-skiing. A total of 19 female able-bodied college students (age 23.2±0.8 years, BMI 20.4±2.2) were subjected to a 30-s and 3-min DP performance tests using a sit-skiing ergometer. Isokinetic muscle strength by the angular velocity of 30 °/second, 60 °/second, and 120 °/second of the shoulder and elbow extensor/flexor were measured with an ISOMED2000 isokinetic system. A medium correlation was found between DP output power and isokinetic upper limb muscle strength (shoulder strength at all speed, r = 0.39-0.74, p < 0.1). Multiple regressions, which were employed to predict power production in the 30-s and 3-min tests, showed that shoulder extension strength at 60 °/second accounted for 34% of the variation in the 30-s test, and 40% of the variance in the 3-min test.