Muscle Reaction Time Research Articles

The Impact of DAZZEON αSleep® Far-Infrared Blanket on Sleep, Blood Pressure, Vascular Health, Muscle Function, Inflammation, and Fatigue.

The application of far-infrared blankets has shown certain benefits in health promotion and therapy, such as improving blood circulation and alleviating muscle pain. However, the effects of such blankets on increasing deep sleep, reducing blood pressure, enhancing memory, dilating microvessels for blood flow, reducing chronic inflammation, and decreasing fatigue remain to be studied. We aim to investigate the effects of the DAZZEON αSleep® far-infrared blanket on these indicators. This study adopted a double-blind design, recruiting 24 male participants aged over 45 years, divided into two groups of 12 each: (A) a placebo group and (B) a DAZZEON αSleep® group. The participants used the blanket every night for two weeks, with sleep records taken using a wearable device and blood pressure, blood oxygen levels, arterial stiffness, and surface temperature measured before and after the intervention. Blood samples were collected for an analysis of inflammation and sleep-related blood indicators (serotonin and melatonin), and exercise tests were conducted to assess fatigue improvement. Compared with before the intervention, the blanket significantly increased changes in grip strength and reaction time. Additionally, it significantly increased blood serotonin, melatonin, and nitric oxide concentrations (p < 0.05), thus significantly increasing deep sleep and REM sleep durations (p < 0.05) and improving subjective sleep quality (p < 0.05). This study confirmed that using the DAZZEON αSleep® far-infrared blanket for 14 consecutive days helps to improve blood circulation, reduce vascular age and arterial stiffness, increase serotonin and melatonin levels, and improve sleep quality, as well as enhances muscle strength and reaction time.

Does Focused Gluteus Medius Muscle Stretching After Total Hip Arthroplasty Work? An Electromyographic Study

BackgroundThe hypothesis of this randomized prospective study was that focused stretching of the gluteus medius muscle, in addition to generalized physical therapy, is likely to improve muscle reaction time and positively impact the return to function of the patient after primary total hip arthroplasty. MethodsWe prospectively recruited 28 patients undergoing primary total hip arthroplasty from January 2021 to January 2023. The control group (13 patients) received a conventional rehabilitation protocol, while the intervention group (15 patients) received focused stretching exercises of the gluteus medius muscle in addition to the conventional rehabilitation protocol. Patients had preoperative and postoperative surface electromyography (sEMG) to assess muscle activity. ResultsPatients in the intervention group after surgery had better muscle activation according to sEMG during walking and during one leg stance compared to the control group. Also, patients from the intervention group had better strength of the gluteus medius muscle after surgery, but this did not reach statistical significance. ConclusionsThe present prospective study demonstrated that implementation of focused gluteus medius muscle stretching results in statistically significantly higher muscle activation as measured by sEMG. The strength of the gluteus medius muscle is also higher as measured using a dynamometer, albeit not reaching statistical significance. Based on the findings of this sEMG study, it appears that focused stretching and strengthening of abductors muscles are beneficial.

Quadriceps muscle reaction time in obese children.

This study aimed to determine the influence of obesity, according to body mass index (BMI) and fat mass percentage, on quadriceps muscle reaction times. The study utilized a cross-sectional design. The sample size consisted of 42 schoolchildren (54.5% girls) aged 11 to 12 years old. Participant measurements included weight and height, which were used to categorize individuals based on BMI. Additionally, the electrical bioimpedance technique was employed to categorize participants based on their body fat percentage. A sudden destabilization test of the lower limb was performed to assess the reaction time of the rectus femoris, vastus medialis, and vastus lateralis muscles. The results show that overweight/obese children have a longer muscle reaction time for both the rectus femoris (β=18.13; p = 0.048) and the vastus lateralis (β=14.51; p = 0.042). Likewise, when the children were classified by percentage of body fat the results showed that overfat/obese children have a longer muscle reaction time for both the rectus femoris (β=18.13; p=0.048) and the vastus lateralis (β=14.51; p=0.042). Our results indicate that BMI and fat mass classification negativity alter the muscle reaction time in children. Overweight/obese or overfat/obese children showed longer reaction times in the rectus femoris and vastus lateralis muscles compared to children with normal weight. Based on these findings, it is suggested that in overweight and obese children, efforts not only focus on reducing body weight but that be complemented with training and/or rehabilitation programs that focus on preserving the normal physiological function of the musculoskeletal system.

Influence of proprioceptive training on fencing athlete’s performance: a clinical trial

Background: Fencing is an agility sport and is characterized by a combination of short and frequent high intensity movements. Proprioceptive training demonstrates a positive effect on athletes' performance. It is effective in increasing dynamic balance by reducing ankle muscle reaction time that stabilize joint. Objective: The aim of this study was to verify influence of a 12-week proprioceptive training program on ankle instability, jumping performance and ankle muscle’s reaction time during Lunge in fencing athletes. Method: The study was a clinical trial, non-randomized, with 19 fencing athletes from 14-35-year-old, divided in intervention group (n=10) and control group (n=9). The study was performed in four stages: familiarization of jump performance; pre-intervention; intervention and post-intervention. At pre-intervention was evaluated jump performance, ankle muscle reaction time and functional ankle instability. At the intervention, athletes performed 30 minutes of proprioceptive training for 12 weeks, three times a week. At post-intervention, the same pre-intervention tests were performed. Data were presented in mean and standard error, submitted to the Generalized Estimates Equations test with Bonferroni post hoc. The level of significance was 0,05. Results: Jump performance decreased significantly in both groups. Anterior tibial muscle reaction time did not differ neither in any of groups, nor in any of legs. The peroneus longus and lateral gastrocnemius reaction time decreased significantly in both groups. Regarding functional ankle instability, athletes had instability at pre- and post-intervention time. Conclusion: Proprioceptive training program was not able to improve jump performance, nor to decrease ankle muscle reaction time or improve athletes' perception of ankle stability.

The Effect of Neural Mobilization on Muscle Strength, Reaction Time And Pain Threshold

ABSTRACT (ENGLISH): &#x0D; Purpose: This study's objective was to assess the effectiveness of neural mobilization on asymptomatic, healthy volunteers' pain, muscle strength, and reaction time.&#x0D; Material and Methods: Hand grip strength, reaction time, and pain thresholds of 50 participiants’ were evaluated using a dynamometer, the Nelson Hand Reaction Test, and a digital algometer, respectively. While the dominant extremities of the participants constituted the neural mobilization group, the non-dominant extremities constituted the control group. The same measurements were repeated in both extremities by the blinded assessor after median nerve mobilization was applied to the dominant upper extremities of participants.&#x0D; Results: When the measurements before and after mobilization were compared in the neural mobilization group, it was seen that the hand grip strength increased (p 0.05); however, a statistically significant decrease was found in reaction time and pain threshold score (p 0.05).&#x0D; Conclusion: Neural mobilization may increase grip strength in healthy individuals but has no effect on pain threshold. Its effect on reaction time can be explained by motor learning. New studies are needed in different disease groups.

만성발목관절불안정성을 가진 농구선수의 신경근 훈련이 발목관절 기능에 미치는 영향

The purpose of this study is to verify the effect of 6-weeks of neuromuscular training on ankle joint function and provide useful information on the prevention of chronic ankle instability(CAI) and improvement of performance for university basketball players. A total of 30 university basketball players who are enrolled in Henan Institute of Science and Technology university were divided into 3 groups based on the CAI standards provided by the International Ankle Consortium: CAI-EG(experimental group, n=10), CAI-CG(control group, n=10), and H-CG(healthy control group, n=10). The neuromuscular training was applied to both CAI-EG and H-CG, and the physical training was applied to only CAI-CG for 6 weeks. Ankle joint function was measured before and after 6-weeks training program application. The Ankle joint function was measured by lower extremity muscle reaction time and performing three types of hop tests. The results of this study showed that the reaction time of the tibialis anterior muscle and peroneus longus muscle of the CAI-EG decreased after application of the program compared to before application(respectively, t=4.194, p=.002; t=3.035, p=.014). As a result of confirming the difference in three types of hop tests, the side hop test record decreased after the program application in all three groups compared to before the application(respectively, t=2.297, p=.047; Z=-2.803, p=.005; t=2.598, p=.029), and the figure-of-8 hop test record also decreased after the program application in all three groups compared to before the application (respectively, t=3.859, p=.004; t=2.638, p=.027; Z=-2.803, p=.005). Square hop test record was decreased after program application in the CAI-EG and CAI-CG compared to before application(respectively, t=2.876, p=.018; t=3.012, p=.015), and it was confirmed that the side hop test record after program application was higher in the CAI-CG than in the H-CG(F=8.116, p=.002). The results showed the effect of neuromuscular training on improving ankle joint function of university basketball players with CAI. Therefore, the neuromuscular training may be a useful program for college basketball players with CAI. Further studies that represent a situation similar to an actual basketball game will provide useful information for preventing CAI and improving performance of college basketball players.

Prospective comparative study between knee alignment-oriented static and dynamic balance exercise in patellofemoral pain syndrome patients with dynamic knee valgus.

Exercise therapy has been reported as an effective treatment method for patellofemoral pain syndrome (PFPS). However, there is a lack of studies regarding the effectiveness of balance exercise in the treatment of patients with PFPS. This study aimed to prospectively compare changes in proprioception, neuromuscular control, knee muscle strength, and patient-reported outcomes between patients with PFPS treated with knee alignment-oriented static balance exercise (SBE) and dynamic balance exercise (DBE). The participants were divided into 2 groups: 17 knee alignment-oriented SBE group and 19 knee alignment-oriented DBE group. Proprioception was assessed by dynamic postural stability using postural stabilometry. Neuromuscular control and knee muscle strength were measured for acceleration time and peak torque in quadriceps muscle using an isokinetic device. Patient-reported outcomes were evaluated using a visual analog scale for pain and the Kujala Anterior Knee Pain Scale. There was greater improvement in dynamic postural stability (0.9 ± 0.3 vs 1.2 ± 0.5; 95% confidence interval [CI]: 0, 0.6; Effect size: 0.72; P = .021) and quadriceps AT (40.5 ± 14.3 vs 54.1 ± 16.9; 95% CI: 2.9, 24.2; Effect size: 0.86; P = .014) in the DBE group compared to the SBE group. Knee alignment-oriented DBE can be more effective in improving dynamic postural stability and quadriceps muscle reaction time compared with the knee alignment-oriented SBE in PFPS patients with dynamic knee valgus.

The Effects Of Qigong Intervention Based On Online Guidance On Postoperative Rehabilitation Of Breast Cancer Patients During Covid-19 Epidemic Period

OBJECTIVE A randomized controlled trials was conducted to explore the rehabilitation effects of online-guided Qigong intervention on quality of life and physical fitness of postoperative breast cancer patients during COVID-19 epidemic period. METHODS Thirty patients aged 35-65 were randomly assigned to an experimental group and a control group. The patients in the experimental group received twice-weekly Qigong exercises under the remote guidance of Qigong instructors for half an hour each time and were encouraged to practice on their own in their free time. The patients in the control group received twice-weekly stretch band training under the remote guidance of exercise instructors for half an hour each time and were encouraged to do walking exercise in free time. Outcomes were measured and recorded at baseline and after 12 weeks of intervention. The quality of life was measured using the Health Survey Short Form SF-36 and the Breast Cancer Specificity Scale FACT-B (version 4.0). Modified Bruce treadmill test was used to estimate cardiopulmonary endurance. Dumbbell Arm Bending Test and Chair Standing and Sitting Test were used to measure the upper limb and Lower extremity muscle strength, respectively. Eight Feet Standing and Walking Test was used to assessment the reaction time. Analysis of covariance adopted for comparisons between groups, and paired t test was used for before-exercise and after-exercise comparisons within a group. RESULTS Thirteen people in each group, completed the study and the outcome measures were included in the data analysis. The results of item of ' Vitality ' in SF-36 showed that the experimental group increased from 74.23 ± 17.89 to 82.23 ± 18.86 and the improvement was better than the control group (p < 0.05). On other SF-36 items, FACT-B all items, endurance, upper and lower limb muscle strength and reaction time, both the experimental group and the control group showed different degrees of improvement, but there was no significant difference between the two groups (p > 0.05). CONCLUSIONQigong exercise and stretch band training combined with walking can improve the quality of life and physical fitness of postoperative breast cancer patients, however Qigong exercise has more advantages in improving the fatigue status of patients.

Ankle reaction times with tray usage following a slip perturbation between subjects with and without chronic low back pain

BackgroundAbnormal stepping strategies have been associated with handheld tasks in subjects with chronic low back pain (LBP). However, the dominant ankle reactions of subjects with LBP remain unclear following a perturbation during handheld tasks. Research questionAre there differences in the reaction times of the ankle muscles during handheld tasks between subjects with and without LBP following a treadmill-induced slip perturbation? MethodsThirty-seven right limb dominant subjects with LBP and 37 subjects without LBP participated in the study. Each subject was introduced to a slip perturbation (1.37 m/sec velocity for 8.22 cm) with and without a handheld tray in random order. Subjects were allowed to recover by stepping forward for a 0.12 s duration while bilateral tibialis anterior (TA) and gastrocnemius (GA) muscle reaction times were measured by electromyography (EMG). ResultsThe EMG results indicated that the groups demonstrated significant interactions on the limb sides and muscles (F = 4.86, p = 0.03). The dominant TA reaction time was significantly faster in the LBP group (t = 2.14, p = 0.03) while holding a tray. SignificanceThe LBP group demonstrated faster reaction times on the dominant TA muscles during perturbations. Clinicians need to consider dominance-dependent compensatory ankle dorsiflexion strategies in LBP patients to help enhance dynamic balance and control.

Preparatory Brain Activity and Anticipatory Postural Control in Cervical Myofascial Trigger Point

Introduction: Neck pain is a highly prevalent disorder in developed countries. A myofascial trigger point (MTrP) is distinguished under the name of the fundamental excessive menstruation for it and certain reason for musculoskeletal dysfunction. MTrP refers to a sensitive spot in a taut band whose stretch and compression can induce pain. Modifications in the motor cortex, sensory input, irritability, and integration are the adaptive mechanisms to pain. Accordingly, this study aimed to investigate the preparatory brain activity and anticipatory postural control in chronic neck pain.&#x0D; Materials and Methods: The study participants included 25 women with an active MTrP in the upper trapezius muscle and 25 healthy women in the control group. We recorded the brain activities from Cz, Pz, and Fz regions and muscle activities of both sides of the upper trapezius, anterior deltoid, cervical and lumbar paraspinal, sternocleidomastoid, and medial head of the gastrocnemius. The participants had to flex their arms in reply to the second sound stimulus, followed by the first sound. Then, their reaction time and brain activity were evaluated.&#x0D; Results: Significant differences between the two groups were detected in brain activities’ measurements and the onset of muscle activation (P&lt;0.001). The exception was the onset of gastrocnemius muscle activation (P&gt;0.05).&#x0D; Conclusion: The current study suggests that active MTrP induces latency and lengthens the muscle reaction time; thus, the production of suitable motion after the stimulus will be affected. Brain alteration after pain damages movement changes and postural control mechanism.

Impact of Startling Acoustic Stimuli on Word Repetition in Individuals With Aphasia and Apraxia of Speech Following Stroke.

The StartReact effect, whereby movements are elicited by loud, startling acoustic stimuli (SAS), allows the evaluation of movements when initiated through involuntary circuitry, before auditory feedback. When StartReact is applied during poststroke upper extremity movements, individuals exhibit increased muscle recruitment, reaction times, and reaching distances. StartReact releases unimpaired speech with similar increases in muscle recruitment and reaction time. However, as poststroke communication disorders have divergent neural circuitry from upper extremity tasks, it is unclear if StartReact will enhance speech poststroke. Our objective is to determine if (a) StartReact is present in individuals with poststroke aphasia and apraxia and (b) SAS exposure enhances speech intelligibility. We remotely delivered startling, 105-dB white noise bursts (SAS) and quiet, non-SAS cues to 15 individuals with poststroke aphasia and apraxia during repetition of six words. We evaluated average word intensity, pitch, pitch trajectories, vowel formants F1 and F2 (first and second formants), phonemic error rate, and percent incidence of each SAS versus non-SAS-elicited phoneme produced under each cue type. For SAS trials compared to non-SAS, speech intensity increased (∆ + 0.6 dB), speech pitch increased (∆ + 22.7 Hz), and formants (F1 and F2) changed, resulting in a smaller vowel space after SAS. SAS affected pitch trajectories for some, but not all, words. Non-SAS trials had more stops (∆ + 4.7 utterances) while SAS trials had more sustained phonemes (fricatives, glides, affricates, liquids; ∆ + 5.4 utterances). SAS trials had fewer distortion errors but no change in substitution errors or overall error rate compared to non-SAS trials. We show that stroke-impaired speech is susceptible to StartReact, evidenced by decreased intelligibility due to altered formants, pitch trajectories, and articulation, including increased incidence of sounds that could not be produced without SAS. Future studies should examine the impact of SAS on voluntary speech intelligibility and clinical measures of aphasia and apraxia.

CONSEQUENCES OF ANKLE SPRAIN ON JOINT INSTABILITY AND REACTION TIME IN HANDBALL PLAYERS

In handball, ankle sprains represent 20% of all injuries and are more common than hand or shoulder injuries. Ligament and soft-structure lesions arising from an ankle sprain involve the aforementioned peripheral receptors and lead to a decrease in the quality of peripheral feedback provided to the central nervous system, which influences the muscle reaction time. Depending on the severity of the sprain, the recovery period ranges between two and four weeks, sometimes being even longer. The literature presents the multiple consequences of ankle sprains on the athletes’ functional abilities, for instance: a decrease in muscle strength and endurance, an increase in the activation time of antagonist muscles, the occurrence of chronic joint instability, the early onset of osteoarthritic processes, which leads a decline in sports performance. The present paper was carried out on 17 handball players aged between 15 and 16 years and aimed to highlight the existence or nonexistence of correlations between the variables represented by: number of ankle sprains, position on the field, degree of joint instability, muscle reaction time, level of pain. Following the analysis of the results, the existence of statistically significant direct connections between the analysed variables is demonstrated. The paper provides specialists with an overview of the functional consequences of ankle sprain, which can have an influence on the results achieved in sports performance.

Comparative Effect of Core Stabilization Exercise and Active Video Gaming on Dynamic Balance in Elderly Female People: a SingleBlind Randomized Controlled Clinical Trial

Objective: The elderly have a decrease in muscle power and cognitive functions, leading to a higher risk of falling. The core stabilization exercise is a standard exercise for the elderly, but is considered as non-interesting and has no immediate feedback. On the other hand, active video gaming is new technology, more interesting and provides immediate feedback. Thus, the objective was to compare the effectiveness of core stabilization exercise (CSE) and active video gaming (AVG) on dynamic balance, core and lower limb muscle strength and reaction time in elderly people.Material and Methods: This study was a single-blind randomized controlled trial design; conducted from January to April, 2019. The participants were 34, healthy, elderly patients; who were randomly assigned to either the CSE group (n=17) or AVG group (n=17). All participants received a training program consisting of 60 minutes, 3 times a week, for 6 weeks. The CSE group received a core stabilization exercise program, while the AVG group received video gaming with balance control on a moveable platform (Sensamove® , the Netherlands). The participants were assessed for dynamic balance, core and lower limb muscle strength, and reaction time at pre-, two, forth, and sixth week. Results: The AVG group showed superior and significant difference to the CSE group in dynamic balance after forth (p-value=0.004; 95% confidence interval (CI), -0.94 to -0.11) and sixth week (p-value=0.001; 95% CI, -1.22 to -0.25) of training, and reaction time after forth (p-value=0.028; 95% CI, -37.89 to –0.24) and sixth week of training (p-value= 0.026; 95% CI, -72.08 to -10.13). However, within group comparison, after sixth weeks of training, the CSE group had significantly increased in core (p-value=0.020; 95% CI, 1.01 to 21.55) and lower limb muscle strength (p-value=0.008; 95% CI, -2.68 to -0.39). In addition, the AVG group had significantly increased in dynamic balance (p-value=0.001; 95% CI, -2.18 to -0.66), lower limb muscle strength (p-value=0.001; 95% CI, -2.38 to -0.66), and reaction time (p-value= 0.007; 95% CI, -120.99 to -22.64).Conclusion: Active video gaming showed better effectiveness than the core stabilization exercise in both dynamic balance and reaction time. Between before and after six weeks of training, the core stabilization exercise increased in core and lower limb muscle strength. In addition, active video gaming increased in dynamic balance, lower limb muscle strength and reaction time. So, active video gaming can be added in generic rehabilitation for improvement of muscle strength, reaction time and balance.

Postural Control and Functional Ankle Stability in Professional and Amateur Skateboarders.

Basic maneuvers in skateboarding, such as the ollie, put the player at high risk for ankle injuries because of the position of the feet required to perform the maneuvers. This study investigated ankle stability and reaction time for the tibialis anterior, fibularis longus, and fibularis brevis in professional and amateur skateboarders. In total, 16 professional and 16 amateur skateboarders were recruited as participants and underwent range of motion assessments, balance testing, and muscle reaction time measurements. The results revealed that professional skateboarders had a significantly smaller inversion angle compared to amateur players, which suggested better joint control and hence greater safety in the former. Balance testing results indicated better balance in professional skateboarders, and healthy skateboarders had better balance than did injured professional and amateur skateboarders. No significant difference in muscle reaction time was observed between amateur and professional skateboarders.

The Influence Of Emotionally Linked Odors On Motor Reaction

Many studies have been investigating the effects of odor on motor actions. However, the effect of odor-induced emotions is less well understood. Arousal and valence, representing fundamental dimensions of emotion, may affect motor reaction differently. PURPOSE: To investigate the influence of odor on reaction time and related muscle activity during elbow flexion when one has a high level of arousal or valence. METHODS: Seven healthy young males (21.7 ± 2.4 yrs) who gave a response of high arousal and negative valence to the odor of ammonia (AMN), and an opposite response to the odor of orange (ORG), were selected as subjects. The subject was quietly seated, wore a plastic mask with a vapored odor-injection pipe, and breathed naturally each of the AMN and ORG odors. A no aroma condition was also included in the test as a control. The subject placed his right arm on the desk while bending the elbow about 90 degrees, and placed his wrist on a load cell secured on the desk. The subject pressed the load cell as quick as possible after hearing a beep sound through a headphone. They repeated the elbow flexion three times with thirty seconds interval. Three trials were performed by each subject for each of the odor conditions. Force signal from the load cell and biceps brachii activity from surface EMG were recorded simultaneously. Force reaction time (FRT), muscle reaction time (MRT), peak force (PF), PF time-of-arrival, and difference between MRT and FRT (mechanical delay time) were evaluated. RESULTS: ANOVA revealed a significant odor effect in the variables of PF (F1,6 = 5.87, P < 0.05) and mechanical delay time (F1,6 = 4.67, P < 0.05). Tukey post-hoc tests revealed that AMN had a higher PF, and a shorter mechanical delay time compared to ORG (p < 0.05, p < 0.05, respectively). CONCLUSIONS: The ammonia odor is linked to arousal, which is strong enough to elevate output of muscle force as well as to facilitate muscle response to flexion of the elbow. Supported by JSPS KAKENHI Grant Number JP 18 K06454.

Muscle Strength and Physical Performance Are Associated with Reaction Time Performance in Older People.

Background: Functional mobility and muscle strength are well known risk factors for sarcopenia. Furthermore, possible associations have been suggested between predisposing factors of sarcopenia and reaction time among the elderly. This study aims to analyze possible associations of functional mobility and muscle strength and reaction times in a population of people aged >60 years. Methods: A total of 290 older people (69.35 ± 5.55 years) participated in this study. The following parameters were assessed: optoacoustic lower-limb reaction time (OALLRT); acoustic lower-limb reaction time (ALLRT); optic lower-limb reaction time (OLLRT, using an optical detection system), functional mobility (through the timed up-and-go test) and muscle strength (using a dynamometer). Results: Our results show that lower values of muscle strength were associated with increased reaction times in OALLRT (β = −0.170; 95% confidence interval −0.011–0.000; R2 = 0.237; p = 0.035) and in ALLRT (β = −0.228; 95% confidence interval −0.011–0.002; R2 = 0.199; p = 0.006). Conclusion: Increased muscle strength (which at low values are risk factors for sarcopenia) was associated with decreased reaction times in people >60 years of age.

USING FAST FOURIER TRANSFORM AND POLYNOMIAL FITTING ON DORSAL FOOT KINEMATICS DATA TO IDENTIFY SIMULATED ANKLE SPRAIN MOTIONS FROM COMMON SPORTING MOTIONS

Ankle sprain is very common in sports, and a commonly suggested etiology is the delayed peroneal muscle reaction time. Recent studies showed the successful attempts to deliver electrical stimulation to the peroneal muscles externally to initiate contraction before it could react, however, the success relies on a workable method to detect ankle sprain injury in time. This study presented a fast Fourier transform and polynomial fitting method with dorsal foot kinematics data for quick ankle sprain detection. Five males performed 100 simulated ankle sprain and 250 common sporting motion trials. Eight gyrometers recorded the three-dimensional angular velocities at 500[Formula: see text]Hz. Data were trimmed with a 0.11[Formula: see text]s window size, the suggested duration of preinjury phase in ankle sprain, and were transformed from time to frequency domain by fast Fourier transform and fitted with a fifth-order polynomial. First-order coefficients from polynomial fitting on frequency space were obtained. The method achieved 97.0% sensitivity and 91.4% specificity in identifying simulated sprains, vertical jump–landing, cutting, stepping-down, running, and walking motions, with vertical jump–landing excluded due to its relatively low specificity (67.3%). The method can be used to detect ankle sprain in sports with mainly floor movements and minimal vertical jump–landing motion.

Electromyographic analysis of ankle muscles in chronic ankle instability during sudden inversion according to visual information provision

Chronic ankle instability is a condition in which the ankle is repetitively giving way, with symptoms such as pain, muscle weakness, and proprioceptive deficits. Therefore, people with chronic ankle instability require complex and systematic interactions between sensory association and the musculoskeletal system. The purpose of this study was to examine changes in ankle muscle activities and reaction times during sudden ankle inversion in chronic ankle instability patients under different visual conditions. Twenty-eight subjects with chronic ankle instability were recruited for the study. All subjects performed a trapdoor platform that was inversion by 25 degrees. This study assessed muscle activity and muscle reaction time during sudden ankle inversion three times with a 60-second rest period between tests with eyes-open and eyes-closed conditions. Muscle activities of tibialis anterior, peroneus longus, and peroneus brevis were significantly diminished with eyes closed, whereas that of gastrocnemius was not significantly different. No significant changes in tibialis anterior, peroneus longus, and peroneus brevis, and gastrocnemius reaction times were observed during sudden ankle inversion in the eyes-open and eyes-closed conditions. Blocking visual information can lower tibialis anterior, peroneus longus, and peroneus brevis muscle activities during postural perturbation in subjects with chronic ankle instability. These results provide insight into the injury mechanism and causes of injury, and thus to improve the existing preventive appliances. Die chronische Instabilität des Sprunggelenks ist eine Erkrankung, die durch wiederholtes Nachgeben des Sprunggelenkes charakterisiert wird, begleitet von Symptomen wie Schmerz, Muskelschwäche und propriozeptiven Defiziten. Menschen mit chronischer Instabilität des Sprunggelenks bedürfen daher komplexer und systematischer Interaktionen von sensorischer Verknüpfung und dem muskuloskelettalen System. Ziel dieser Studie war die Untersuchung der Veränderungen der Muskelaktivitäten im Sprunggelenk sowie der Reaktionszeiten während einer plötzlichen Gelenkkippung bei Patienten mit chronischer Instabilität des Sprunggelenks unter verschiedenen visuellen Bedingungen. 28 Patienten mit chronischer Instabilität des Sprunggelenks nahmen an der Studie teil. Alle Teilnehmer wurden auf einer Kippplattform mit 25 Grad Neigung untersucht. Im Rahmen der Studie wurden während einer plötzlichen Gelenkkippung drei Mal Daten zu Muskelaktivität und Reaktionszeit erhoben, mit jeweils 60 Sekunden Pause zwischen den Tests sowie mit geöffneten und geschlossenen Augen. Bei geschlossenen Augen waren die Muskelaktivitäten im Tibialis anterior, Peroneus longus und Peroneus brevis signifikant vermindert, während im Gastrocnemius hier keine signifikante Veränderung gemessen wurde. Bei der Messung der Reaktionszeiten im Tibialis anterior, Peroneus longus, Peroneus brevis und Gastrocnemius während einer plötzlichen Sprunggelenkkippung mit geöffneten und mit geschlossenen Augen traten keine signifikanten Veränderungen auf. Das Fehlen visueller Informationen bei Stellungsschwankungen kann die Muskelaktivität im Tibialis anterior, Peroneus longus und Peroneus brevis bei Patienten mit chronischer Instabilität des Sprunggelenks verringern. Die vorliegenden Ergebnisse gewähren Einblick in die Natur und die Ursache der Verletzung und unterstützen so die Verbesserung existierender Vorbeugemaßnahmen.

Comparison of muscle strength and neuromuscular control up to 1 year after anterior cruciate ligament reconstruction between patients with dominant leg and non-dominant leg injuries

BackgroundThere has not been an investigation to determine whether leg dominance affects the recovery of quadriceps and hamstring strength, muscle reaction time (acceleration time, AT), and postural stability after anterior cruciate ligament (ACL) reconstruction in recreational-level athletic patients. MethodsA total of 100 patients with isolated ACL injuries (58 patients had dominant leg injuries; 42 patients had non-dominant leg injuries) participated. All patients received an anatomical single-bundle ACL reconstruction using an auto-hamstring tendon graft without preoperative rehabilitation. Leg dominance was defined as the kicking leg. The quadriceps and hamstring strength, AT, and postural stability (overall stability index (OSI)) of both legs were assessed at three different time points (preoperative, 6 months, 12 months), using an isokinetic dynamometer and postural stabilometry system. ResultsAll patients in both groups showed gradual improvement in quadriceps and hamstring muscle strength in the operated legs up to 1 year postoperatively. However, the mean value of quadriceps strength was lower in the operated non-dominant leg than the operated dominant leg 6 months postoperatively (P = 0.048). The AT and OSI of the operated legs in both groups recovered significantly 6 months postoperatively compared with their preoperative values; however, the AT and OSI values after 6 and 12 months were similar. ConclusionQuadriceps strength of the operated non-dominant leg was lower than that of the operated dominant leg 6 months postoperatively; however, the strength of the quadriceps and hamstring muscles was not different after 12 months between the operated dominant and non-dominant legs. Clinicians and physical therapists should consider these results during early rehabilitation and identify effective protocols to enhance quadriceps strength, especially in patients with non-dominant leg injuries.

Delayed peroneal muscle reaction time in male amateur footballers during a simulated prolonged football protocol

ABSTRACT Peroneal muscle fatigue could result in ankle inversion sprain injuries. This study investigated the peroneal muscle reaction time during a simulated prolonged football protocol. Nine male footballers completed a 105-minute simulated prolonged football protocol. The peroneal muscle reaction time to an ankle inversion perturbation was measured every 15 minutes by a surface electromyography system sampling at 1000 Hz. One-way repeated ANOVA with post-hoc paired t-test showed a steady upward trend starting from 48.9 ms at baseline to 57.1 ms at the end of the first half, followed by a recovery back to 50.9 ms at the start of the second half and a further delay in the last 30 minutes to 60.2 ms at the end of the protocol. Delayed peroneal muscle reaction was found after 30 minutes of the first half and 15 minutes of the second half of a football match. The risk of ankle sprain could increase in the latter minutes in each half protocol. Thus, prevention injury training strategies should focus on these specific durations in football matches.