scholarly journals The effects of passive stretching plus vibration on strength and activation of the plantar flexors

2016 ◽  
Vol 41 (9) ◽  
pp. 917-923 ◽  
Author(s):  
Jonathan D. Miller ◽  
Trent J. Herda ◽  
Michael A. Trevino ◽  
Eric M. Mosier
Keyword(s):  
Plantar Flexion ◽  
Muscle Length ◽  
Peak Torque ◽  
Plantar Flexors ◽  
Cohen’S D ◽  
Passive Stretching ◽  
Before And After ◽  
Cohen's D ◽  
Voluntary Contractions ◽  
Musculotendinous Stiffness

This study examined the effects of passive stretching only (PS+CON) and passive stretching with the addition of continuous vibration (VIB) during post-passive stretching tests (PS+VIB) on peak torque (PT), percent voluntary inactivation (%VI), single stimulus twitch torque (TTSINGLE), and doublet stimuli twitch torque (TTDOUBLET) of the plantar flexors at a short (20° plantar flexion (PF)) and long muscle length (15° dorsiflexion (DF)). Fourteen healthy men (age = 22 ± 3 years) performed isometric maximal voluntary contractions at PF and DF, and passive range of motion (PROM) assessments before and after 8 × 30-s passive stretches without (PS+CON) or with VIB (PS+VIB) administered continuously throughout post-passive stretching tests. The passive properties of the muscle tendon unit were assessed pre- and post-passive stretching via PROM, passive torque (PASSTQ), and musculotendinous stiffness (MTS) measurements. PT, TTSINGLE, and TTDOUBLET decreased, whereas, %VI increased following passive stretching at PF and DF (P < 0.05) with no significant differences between PS+CON and PS+VIB. PASSTQ and MTS decreased while PROM increased post-passive stretching during both trials (P < 0.05). The stretching-induced force/torque deficit and increases in %VI were evident following passive stretching at short and long muscle lengths. Although not statistically significant, effect size calculations suggested large and moderate differences in the absolute changes in PT (Cohen’s d = 1.14) and %VI (Cohen’s d = 0.54) from pre- to post-passive stretching between treatments, with PS+VIB having greater decreases of PT and higher %VI than PS+CON. The decrement in PT following passive stretching may be primarily neural in origin.

Muscle Strength Deficit though Intact Proprioception after Lateral Ankle Sprain without Persistent Instability

2021 ◽  
Author(s):  
Adel M. Madkhali ◽  
Shibili Nuhmani
Keyword(s):  
Ankle Sprain ◽  
Peak Torque ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Lateral Ankle Sprain ◽  
Lateral Ankle ◽  
Cohen’S D ◽  
History Of ◽  
Cohen's D

Abstract Background Lateral ankle sprain is one of the most common injuries in competitive sports. Previous studies which investigated muscle strength and proprioception (joint position sense) focused on subjects who sustained ankle sprain with instability. It is also important to investigate strength deficits and proprioception in subjects with a history of ankle sprain without instability. Therefore the aim of the study is to investigate proprioception and muscle strength deficits in athletes with lateral ankle sprain. Methods Twenty-four male athletes with a history of lateral ankle sprain and 24 age-matched controls (mean age of 22.42±4.13 years, mean height of 173±5.73 cm, and mean weight of 71.20±7.55 Kg) participated in this cross-sectional study. Peak torque and peak torque ratio at speeds of 30 and 120°/s for concentric and eccentric ankle inversion/eversion were evaluated using an isokinetic dynamometer. The joint position sense of the ankle joint was evaluated using an active angle reproduction test. Result Peak torque produced was significantly less in subjects with history of ankle sprain in concentric inversion 30°/s(t(47)=4.11; p=0.000, Cohen’s d=1.29), concentric inversion 120°/s (t(47)=3.01; p=0.006, Cohen’s d=1.13), concentric eversion 30°/s (t(47)=3.85; p=0.001, Cohen’s d=1.24) and concentric eversion 120°/s (t(47)=3.15; p=0.005, Cohen’s d=1.09). At the same time there was no significant difference observed in eccentric eversion peak torque in both speed (eccentric eversion 30°/s p=0.079; eccentric eversion 120°/s p=0.867) between experimental and control group. No significant difference was found in the joint position sense in the maximal active inversion −5° position (p=0.312) and the 15° inversion position (P=0.386) between both group. Conclusion The study’s results reported a significantly less peak torque of invertors and evertors during concentric movements in athletes with history of ankle sprain. At the same time, no significant difference reported in the evertor/invertor peak torque ratio, and active joint position sense between the 2 groups.

scholarly journals Effects of Intermittent and Continuous Static Stretching on Range of Motion and Musculotendinous Viscoelastic Properties Based on a Duration-Matched Protocol

2021 ◽  
Vol 18 (20) ◽  
pp. 10632
Author(s):  
Kensuke Oba ◽  
Mina Samukawa ◽  
Yosuke Abe ◽  
Yukino Suzuki ◽  
Miho Komatsuzaki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Range Of Motion ◽  
Repeated Measures ◽  
Plantar Flexors ◽  
Constant Torque ◽  
Resistive Torque ◽  
Repeated Measures Analysis ◽  
Before And After ◽  
Musculotendinous Stiffness ◽  
Torque Angle

The different effects of intermittent and continuous stretching on the mechanical properties of the musculotendinous complex have been unclear. This study aimed to compare the effects of intermittent and continuous stretching for the same duration on the range of motion (ROM), passive resistive torque (PRT), and musculotendinous stiffness (MTS) of ankle plantar flexors. Eighteen healthy young men participated in the study. Intermittent (four sets × 30 s) and continuous stretching (one set × 120 s) were performed in random orders on two separate days. Both stretching protocols were conducted using a dynamometer with a constant torque applied. ROM and PRT were determined using a dynamometer, and MTS was calculated using the torque–angle relationship measured before and after stretching. Two-way repeated measures analysis of variance was performed for all parameters. Both intermittent and continuous stretching significantly increased ROM and decreased PRT and MTS (p < 0.05). Intermittent stretching led to greater changes in ROM and PRT than continuous stretching. However, the reduction in MTS did not differ between the two conditions. These results suggest that intermittent stretching is more effective in increasing ROM and changing the mechanical properties of the musculotendinous complex.

scholarly journals Cognitive consequences of COVID-19: results of a cohort study from South America

2021 ◽  
Author(s):  
Lucía Crivelli ◽  
Ismael Calandri ◽  
Nicolás Corvalán ◽  
María Agostina Carello ◽  
Greta Keller ◽  
...  
Keyword(s):  
Executive Functions ◽  
Cognitive Dysfunction ◽  
Psychiatric Symptomatology ◽  
Cohen’S D ◽  
Cognitive Risk ◽  
Cognitive Complaint ◽  
Visuospatial Skills ◽  
Before And After ◽  
Cohen's D ◽  
The Impact

ABSTRACT Background: Neurological and psychiatric manifestations associated with SARS-CoV-2 infection have been reported throughout the scientific literature. However, studies on post-COVID cognitive impairment in people with no previous cognitive complaint are scarce. Objective: We aim to investigate the impact of COVID-19 on cognitive functions in adults without cognitive complaints before infection and to study cognitive dysfunction according to disease severity and cognitive risk factors. Methods: Forty-five post-COVID-19 patients and forty-five controls underwent extensive neuropsychological evaluation, which assessed cognitive domains such as memory, language, attention, executive functions, and visuospatial skills, including psychiatric symptomatology scales. Data were collected on the severity of infection, premorbid medical conditions, and functionality for activities of daily living before and after COVID-19. Results: Significant differences between groups were found in cognitive composites of memory (p=0.016, Cohen’s d= 0.73), attention (p<0.001, Cohen’s d=1.2), executive functions (p<0.001, Cohen’s d=1.4), and language (p=0.002, Cohen’s d=0.87). The change from premorbid to post-infection functioning was significantly different between severity groups (WHODAS, p=0.037). Self-reported anxiety was associated with the presence of cognitive dysfunction in COVID-19 subjects (p=0.043). Conclusion: Our results suggest that the presence of cognitive symptoms in post-COVID-19 patients may persist for months after disease remission and argue for the inclusion of cognitive assessment as a protocolized stage of the post-COVID examination. Screening measures may not be sufficient to detect cognitive dysfunction in post-COVID-19 patients.

scholarly journals A Pilot Study on Playback Theatre as a Therapeutic Aid after Natural Disasters: Brain Connectivity Mechanisms of Effects on Anxiety

2020 ◽  
Vol 4 ◽  
pp. 247054702096656
Author(s):  
Sarat Munjuluri ◽  
Peter K. Bolin ◽  
Y. T. Amy Lin ◽  
Nina L. Garcia ◽  
Leslie Gauna ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Natural Disasters ◽  
Resting State ◽  
Underlying Mechanism ◽  
Post Traumatic Stress ◽  
Resting State Functional Connectivity ◽  
Playback Theatre ◽  
Cohen’S D ◽  
Before And After ◽  
Cohen's D

Background Natural disasters can affect mental health and result in symptoms of depression, anxiety, and post-traumatic stress disorder (PTSD). Playback Theatre (PT) is a form of improvisation where actors play-back personal stories told by audience members. Whether PT can be therapeutic in post-disaster settings is not known. Method We used a series of PT performances and studied levels of depression, anxiety, and PTSD symptoms in a sample of 13 people affected by Hurricane Harvey that happened in Houston, TX, August 2017. Brain imaging, specifically resting state functional connectivity of the amygdala was also studied before and after the PT performances. Results Both anxiety ( p = .001, Cohen’s d = –1.25) and PTSD ( p = .002, Cohen’s d = –1.0) symptoms significantly decreased after a series of 4 PT performances from January 2019 – February 2019. Depression reduction was not significant. We performed resting state functional connectivity (RSFC) MRI before and after the series of performances. We used the right and left amygdala as seeds for RSFC analysis and found that the connectivity between the left amygdala and the bilateral supramarginal gyri was increased after PT. The bilateral supramarginal connectivity with the default mode and the saliency networks increased too, which correlated with reduction in anxiety scores. Conclusions PT may offer a form of intervention for anxiety caused by disasters. An increase in left amygdala/supramarginal gyri connectivity may be the underlying mechanism.

Mechanical and electromyographic analysis of reciprocal inhibition at the human ankle joint

1995 ◽  
Vol 74 (2) ◽  
pp. 849-855 ◽  
Author(s):  
T. Sinkjaer ◽  
J. Nielsen ◽  
E. Toft
Keyword(s):  
Ankle Joint ◽  
Stretch Reflex ◽  
Plantar Flexion ◽  
Joint Stiffness ◽  
Common Peroneal Nerve ◽  
Reciprocal Inhibition ◽  
Mechanical Effect ◽  
Voluntary Contraction ◽  
Plantar Flexors ◽  
Before And After

1. The purpose of the present study is to investigate how reciprocal inhibition influences the mechanical and electromyographic (EMG) properties of the ankle plantar flexors in humans during a voluntary contraction. 2. At different levels of maintained plantar flexion contractions ranging from 0 to 20 Nm, the size of the soleus EMG stretch reflex and the ankle joint stiffness (ration between the torque increment and the amplitude of the stretch) were measured in response to an imposed dorsiflexion. At matched plantar flexion contraction levels, stretch responses were compared before and after reversible block of the common peroneal nerve (CPN). Stretch responses were also measured during an attempted voluntary fictive dorsiflexion after CPN block. 3. In the preactivated soleus muscles, the phasic EMG response to stretch consisted of two peaks labeled M1 and M2. After CPN block, the M1 short-latency stretch reflex on average increased by 25 +/- 5.7%, mean +/- SD (P < 0.001), and the M2 stretch reflex increased on average by 29 +/- 13.0% (P = 0.002). 4. The total stiffness of the ankle joint during a stretch is the sum of the nonreflex and the reflex mediated stiffness. The total stiffness after CPN block increased on average by 13 +/- 2.7% (P = 0.002) and the estimated reflex stiffness by 33 +/- 6.5% (P < 0.001). 5. When the subjects were asked to make a strong dorsiflexion after CPN block, the soleus stretch reflex was depressed to the extent that the reflex mediated mechanical effect around the ankle joint was abolished.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Psychological Risk of Minimal Risk Activities: A Pre- and Posttest Study Using the Self-Assessment Manikin

2018 ◽  
Vol 14 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Maureen Murdoch ◽  
Melissa Ruth Partin ◽  
Derek Vang ◽  
Shannon Marie Kehle-Forbes
Keyword(s):  
Care Physician ◽  
The Self ◽  
Mental Health Provider ◽  
Minimal Risk ◽  
Department Of Veterans Affairs ◽  
Self Assessment ◽  
Cohen’S D ◽  
Before And After ◽  
Valence And Arousal ◽  
Cohen's D

It is difficult to apply U.S. Federal Code of Regulation’s criterion for “minimal risk,” because benchmarks of minimal risk have not been quantified. Our goal was to examine the psychological risks of several day-to-day activities. Using the Self-Assessment Manikin (SAM), we assessed the state valence and arousal of 432 patients and employees at a large Midwestern Department of Veterans Affairs medical facility before and after they had their blood drawn, saw their primary care physician or mental health provider, or took part in an exercise class. Exercise was associated with near-large to large salutary effects (Cohen’s d = 0.76-1.17); other effects were small or moderate in positive directions (Cohen’s d = 0.02-0.51). Our findings are a promising start toward establishing benchmarks and quantifying the psychological harms of minimal risk activities. Estimates such as these may help researchers determine whether their own research exceeds minimal risk.

scholarly journals Lengthening the Hamstring Muscles Without Stretching Using “Awareness Through Movement”

2006 ◽  
Vol 86 (12) ◽  
pp. 1641-1650 ◽  
Author(s):  
James Stephens ◽  
Joshua Davidson ◽  
Joseph DeRosa ◽  
Michael Kriz ◽  
Nicole Saltzman
Keyword(s):  
Muscle Length ◽  
Knee Extension ◽  
Control Group ◽  
Active Movement ◽  
Hamstring Muscle ◽  
Screening Criteria ◽  
Passive Stretching ◽  
Hamstring Muscles ◽  
Before And After ◽  
And Control

Abstract Background and PurposePassive stretching is widely used to increase muscle flexibility, but it has been shown that this process does not produce long-term changes in the viscoelastic properties of muscle as originally thought. The authors tested a method of lengthening hamstring muscles called “Awareness Through Movement” (ATM) that does not use passive stretching. Subjects. Thirty-three subjects who were randomly assigned to ATM and control groups met the screening criteria and completed the intervention phase of the study. Methods. The ATM group went through a process of learning complex active movements designed to increase length in the hamstring muscles. Hamstring muscle length was measured before and after intervention using the Active Knee Extension Test. Results. The ATM group gained significantly more hamstring muscle length (+7.04°) compared with the control group (+1.15°). Discussion and Conclusions. The results suggest that muscle length can be increased through a process of active movement that does not involve stretching. Further research is needed to investigate this finding.

scholarly journals Pre-medical students’ perceptions of educational environment and their subjective happiness: a comparative study before and after the COVID-19 pandemic

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yanyan Lin ◽  
Ye Ji Kang ◽  
Hyo jeong Lee ◽  
Do-Hwan Kim
Keyword(s):  
Medical Students ◽  
Effect Size ◽  
Educational Environment ◽  
Medium Effect ◽  
Subjective Happiness ◽  
Social Self ◽  
Self Perceptions ◽  
Cohen’S D ◽  
Before And After ◽  
Cohen's D

Abstract Background The COVID-19 pandemic necessarily changed pre-medical students’ educational environment into an online format—and students’ subjective happiness (SH) is highly impacted by their educational environment. This study investigates changes in pre-medical students’ perceptions of their educational environment and their SH before and after the pandemic, as well as explores the predictors related to their SH. Methods The Korean version of the Dundee Ready Educational Environment Measure (DREEM) questionnaire and single-item measures of SH and professional identity (PI) were used. The t-test was employed to analyze the differences of the SH, PI, and DREEM subscales scores before and after the onset of COVID-19. Cohen’s d was used as effect size and correlations between SH and different subscales of DREEM were analyzed using Pearson’s correlation. The multiple regression analysis was performed to reveal associations between predictors and SH. Results A total of 399 pre-medical students completed the survey both before and after the COVID-19 pandemic. The DREEM scores and all subscales scores significantly increased but each presents a different effect size. Students’ Perceptions of Learning (SPL: Cohen’s d = 0.97), Students’ Perceptions of Teaching (SPT: Cohen’s d = 1.13), and Students’ Perceptions of Atmosphere (SPA: Cohen’s d = 0.89) have large effect sizes. Students’ Academic Self-Perceptions (SASP: Cohen’s d = 0.66) have a medium effect size and Students’ Social Self-Perceptions (SSSP: Cohen’s d = 0.40) have a small effect size. In contrast, no significant change was noted in the SH and PI. Both PI and SSSP impacted SH before COVID-19, but after the pandemic, SH was impacted by SPL, SPA, and SSSP. Conclusions Students’ overall perception of their educational environment was more positive after the onset of COVID-19, but their social self-perceptions improved the least. Additionally, SSSP is the only predictor of SH both before and after the pandemic. The findings of this study suggest that educational institutions must pay attention to students’ social relationships when trying to improve their educational environment. Furthermore, so as to increase students’ SH, development of both educational environment and PI is essential.

Effects of 22 °C muscle temperature on voluntary and evoked muscle properties during and after high-intensity exercise

2007 ◽  
Vol 32 (6) ◽  
pp. 1043-1051 ◽  
Author(s):  
Eric J. Drinkwater ◽  
David G. Behm
Keyword(s):  
High Intensity ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Contractile Properties ◽  
Muscle Temperature ◽  
Plantar Flexors ◽  
Muscle Properties ◽  
Time To Peak ◽  
Cohen’S D ◽  
Cohen's D

The purpose of this study was to investigate the effect of 22 °C local muscle temperature of intact human plantar flexors performing fatiguing contractions on evoked and voluntary contractile properties before and after fatigue. Twelve subjects were tested on plantar flexor voluntary torque, percent muscle activation derived from twitch interpolation, integrated electromyographic (iEMG) activity, and evoked torque and temporal characteristics of maximal twitch and tetanic stimulations before fatigue and 1, 5, and 10 min after intermittent, high-intensity, isometric fatigue under both normothermic and hypothermic conditions. Hypothermic and normothermic changes between time points were analysed by repeated-measures analysis of variance. Normothermic fatigue induced small to large effects (Cohen’s d: 0.29–3.06) on voluntary and evoked contractile properties, whereas most effects of unfatigued hypothermia were limited to rate-dependent processes (Cohen’s d: 0.78–1.70). Most tetanic properties were potentiated 1 min after normothermic fatigue, but remained unchanged by hypothermic fatigue, resulting in significant differences between the two conditions. Soleus iEMG significantly declined 1 min after normothermic fatigue (–29%), but not after hypothermic fatigue. Twitch torque was potentiated by 29% one minute after fatigue while normothermic, but was potentiated by 46% while hypothermic; rate of twitch torque development and time to peak twitch were potentiated by 39% and 10% while normothermic, but 89% and 28% while hypothermic. Although voluntary contractile properties are generally impaired soon after normothermic fatigue, most were not after hypothermic fatigue. Furthermore, evoked contractile properties were generally higher 1 min after hypothermic fatigue. We conclude that the hypothermic condition slows the recovery of potentiated evoked contractile properties back to baseline values.

Tendon elongation influences the amplitude of interpolated doublets in the assessment of activation in elderly men

2005 ◽  
Vol 98 (1) ◽  
pp. 221-226 ◽  
Author(s):  
Christopher I. Morse ◽  
Jeanette M. Thom ◽  
Karen M. Birch ◽  
Marco V. Narici
Keyword(s):  
Ankle Joint ◽  
Joint Angle ◽  
Plantar Flexion ◽  
Negative Association ◽  
Plantar Flexors ◽  
Joint Angles ◽  
Elderly Men ◽  
Electromechanical Delay ◽  
Tendon Elongation ◽  
Voluntary Contractions

This study investigated the influence of tendon elongation (TE) on postcontraction doublet (PCD) torque in the assessment of activation in the plantar flexors of nine elderly men (EM, age 73.7 ± 3.6 yr) and nine young men (YM, age 24.7 ± 4.7 yr). Plantar flexion maximal voluntary contractions (MVC) and activation were assessed at ankle joint angles of −20° (dorsiflexion), 0°, and 20° (plantar flexion). Across the ankle joint angles tested, compared with YM, the EM had a 36–49% lower plantar flexion MVC ( P < 0.01), TE was greater by 25–31% ( P < 0.01), and electromechanical delay was 65–108% greater ( P < 0.01). Activation (PCD torque to interpolated doublet torque) was 15% lower in EM compared with YM at −20° ( P < 0.05), but no different at 0 and 20°. In the EM, PCD torque relative to MVC torque was significantly lower at 20° compared with 0° ( P < 0.05). Electromechanical delay was positively correlated with TE ( R2 = 0.489, P < 0.01). In conclusion, this investigation demonstrates that, although a negative association exists between TE and PCD torque, the consequence of a greater TE on the estimation of activation in EM is negligible. This is due to a greater influence of ankle joint angle on the occlusion of a superimposed doublet, which counteracts the lesser influence of joint angle on TE and PCD torque. However, a greater TE in EM was found to significantly increase electromechanical delay, which is expected to influence the time needed for postural readjustments.

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