Muscle activity and inactivity periods during normal daily life

Recent findings suggest that not only the lack of physical activity, but also prolonged times of sedentary behaviour where major locomotor muscles are inactive, significantly increase the risk of chronic diseases. The purpose of this study was to provide details of quadriceps and hamstring muscle inactivity and activity during normal daily life of ordinary people. Eighty-four volunteers (44 females, 40 males, 44.1±17.3 years, 172.3±6.1 cm, 70.1±10.2 kg) were measured during normal daily life using shorts measuring muscle electromyographic (EMG) activity (recording time 11.3±2.0 hours). EMG was normalized to isometric MVC (EMGMVC) during knee flexion and extension, and inactivity threshold of each muscle group was defined as 90% of EMG activity during standing (2.5±1.7% of EMGMVC). During normal daily life the average EMG amplitude was 4.0±2.6% and average activity burst amplitude was 5.8±3.4% of EMGMVC (mean duration of 1.4±1.4 s) which is below the EMG level required for walking (5 km/h corresponding to EMG level of about 10% of EMGMVC). Using the proposed individual inactivity threshold, thigh muscles were inactive 67.5±11.9% of the total recording time and the longest inactivity periods lasted for 13.9±7.3 min (2.5–38.3 min). Women had more activity bursts and spent more time at intensities above 40% EMGMVC than men (p<0.05). In conclusion, during normal daily life the locomotor muscles are inactive about 7.5 hours, and only a small fraction of muscle\u27s maximal voluntary activation capacity is used averaging only 4% of the maximal recruitment of the thigh muscles. Some daily non-exercise activities such as stair climbing produce much higher muscle activity levels than brisk walking, and replacing sitting by standing can considerably increase cumulative daily muscle activity

The Open Brain Consent: Informing research participants and obtaining consent to share brain imaging data

Having the means to share research data openly is essential to modern science. For human research, a key aspect in this endeavor is obtaining consent from participants, not just to take part in a study, which is a basic ethical principle, but also to share their data with the scientific community. To ensure that the participants' privacy is respected, national and/or supranational regulations and laws are in place. It is, however, not always clear to researchers what the implications of those are, nor how to comply with them. The Open Brain Consent (https://open-brain-consent.readthedocs.io) is an international initiative that aims to provide researchers in the brain imaging community with information about data sharing options and tools. We present here a short history of this project and its latest developments, and share pointers to consent forms, including a template consent form that is compliant with the EU general data protection regulation. We also share pointers to an associated data user agreement that is not only useful in the EU context, but also for any researchers dealing with personal (clinical) data elsewhere

Voimaharjoittelun vaikutukset keskimmäisen ja suoran reisilihaksen väliseen dynamiikkaan polven koukistus-ojennusliikkeessä

Tässä tutkimuksessa tarkastellaan nopeuskoodatun magneettikuvauksen avulla voimaharjoittelun vaikutuksia nelipäisen reisilihaksen mekaniikkaan. Tutkimukseen osallistui 14 koehenkilöä, joista seitsemän voimaharjoitteli 20 viikon ajan. Yhden toiston maksimitulos jalkakyykyssä parani koeryhmällä (33,1 ± 12,1) % ja vertailuryhmällä (6,6 ± 5,1) %. Molemmat tulokset olivat tilastollisesti merkitseviä (koeryhmä < 0.001, vertailuryhmä < 0.05). Ryhmän ja ajan yhteisvaikutus oli merkitsevä ( < 0.001). Voimaharjoittelujaksoa ennen ja sen jälkeen koehenkilöt tekivät pienellä kuormalla toistuvaa polven ojennus-koukistusliikettä magneettikuvauslaitteessa. Suoran reisilihaksen ja keskimmäisen reisilihaksen välisen kalvojänteen reunat merkittiin kuviin, ja niiden liikettä seurattiin läpi ojennus-koukistussyklin. Kuvista laskettiin siirtymät, venymät ja liukumat. Kalvojänteen keskimmäisen reisilihaksen puoli liikkui keskimäärin merkitsevästi enemmän kuin suoran reisilihaksen puoli. Voimaharjoittelulla ei havaittu olevan tilastollisesti merkitsevää vaikutusta mihinkään lasketuista muuttujista. Nelipäisen reisilihaksen sisäisessä dynamiikassa ja venymissä oli eroja koehenkilöiden ja mittauskertojen välillä, mutta ne eivät näyttäneet olevan yhteydessä voimaharjoitteluun. Tulosten perusteella ei voida sanoa, johtuvatko erot rakenteellisesta vaihtelusta vai esimerkiksi eroista hermostollisen aktivaation malleissa.In this study, we investigated how strength training affects the dynamics between rectus femoris (RF) and vastus intermedius (VI) using velocity-encoded phase-contrast magnetic resonance imaging (VE-PC MRI). One half of the group of 14 subjects underwent 20 weeks of strength training. The other half did not train. The training group increased their half-squat one-repetition maximum (33,1 ± 12,1) %, while the control group increased their maximum (6,6 ± 5,1) %. Both of the changes were statistically significant ( < 0.001 and < 0.05, respectively), and so was the group-by-time interaction ( < 0.001). Before and after the strength-training period, VE-PC MRI scans were taken while the subjects performed knee extension-flexion cycles against low load. Edges of the aponeurosis structure between RF and VI were marked on the images and tracked throughout the cycle. Displacement, tensile strain and shear strain were calculated. On average, displacement was significantly greater on the VI side of the aponeurosis, but there was variation between subjects. Training did not have a significant effect on any of the calculated variables. Muscle dynamics and strain seemed to vary by time and by subject, but the variation was not linked to strength training. It remains unclear whether the variation is due to differences in the muscle architecture, or for example differences in neural activation patterns

Sensitivity and specificity of measuring children's free-living cycling with a thigh-worn Fibion accelerometer

Funding Information: This work was supported by the Ministry of Education and Culture, Finland under Grants OKM/30/626/2019 and OKM/1097/626/2020. The funding agency had no role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. Publisher Copyright: 2023 Pesola, Esmaeilzadeh, Hakala, Kallio, Berg, Havu and Rinne.Objective: Cycling is an important part of children's active travel, but its measurement using accelerometry is a challenge. The aim of the present study was to evaluate physical activity duration and intensity, and sensitivity and specificity of free-living cycling measured with a thigh-worn accelerometer. Methods: Participants were 160 children (44 boys) aged 11.5 ± 0.9 years who wore a triaxial Fibion® accelerometer on right thigh for 8 days, 24 h per day, and reported start time and duration of all cycling, walking and car trips to a travel log. Linear mixed effects models were used to predict and compare Fibion-measured activity and moderate-to-vigorous activity duration, cycling duration and metabolic equivalents (METs) between the travel types. Sensitivity and specificity of cycling bouts during cycling trips as compared to walking and car trips was also evaluated. Results: Children reported a total of 1,049 cycling trips (mean 7.08 ± 4.58 trips per child), 379 walking trips (3.08 ± 2.81) and 716 car trips (4.79 ± 3.96). There was no difference in activity and moderate-to-vigorous activity duration (p >.105), a lower cycling duration (−1.83 min, p <.001), and a higher MET-level (0.95, p <.001) during walking trips as compared to cycling trips. Both activity (−4.54 min, p <.001), moderate-to-vigorous activity (−3.60 min, p <.001), cycling duration (−1.74 min, p <.001) and MET-level (−0.99, p <.001) were lower during car trips as compared to cycling trips. Fibion showed the sensitivity of 72.2% and specificity of 81.9% for measuring cycling activity type during the reported cycling trips as compared to walking and car trips when the minimum required duration for cycling was less than 29 s. Conclusions: The thigh-worn Fibion® accelerometer measured a greater duration of cycling, a lower MET-level, and a similar duration of total activity and moderate-to-vigorous activity during free-living cycling trips as compared to walking trips, suggesting it can be used to measure free-living cycling activity and moderate-to-vigorous activity duration in 10–12-year-old children.Peer reviewe

Muscle Inactivity and Activity Patterns after Sedentary-Time Targeted Randomized Controlled Trial

Purpose: Interventions targeting sedentary time are needed. We used detailed EMG recordings to study the short-term effectiveness of simple sedentary time-targeted tailored counseling on the total physical activity spectrum. Methods: This cluster randomized controlled trial was conducted between 2011 and 2013 (InPact, ISRCTN28668090), and short-term effectiveness of counseling is reported in the present study. A total of 133 office workers volunteered to participate, from which muscle activity data were analyzed from 48 (intervention, n = 24; control, n = 24). After a lecture, face-to-face tailored counseling was used to set contractually binding goals regarding breaking up sitting periods and increasing family based physical activity. Primary outcome measures were assessed 11.8 ± 1.1 h before and a maximum of 2 wk after counseling including quadriceps and hamstring muscle inactivity time, sum of the five longest muscle inactivity periods, and light muscle activity time during work, commute, and leisure time. Results: Compared with those in the controls, counseling decreased the intervention group’s muscle inactivity time by 32.6 ± 71.8 min from 69.1% ± 8.5% to 64.6% ± 10.9% (whole day, P < 0.05; work, P < 0.05; leisure, P < 0.05) and the sum of the five longest inactivity periods from 35.6 ± 14.8 to 29.7 ± 10.1 min (whole day, P < 0.05; leisure, P < 0.01). Concomitantly, light muscle activity time increased by 20.6 ± 52.6 min, from 22.2% ± 7.9% to 25.0% ± 9.7% (whole day, P < 0.05; work, P < 0.01; leisure, P < 0.05), and during work time, average EMG amplitude (percentage of EMG during maximal voluntary isometric contraction (MVC) (%EMGMVC)) increased from 1.6% ± 0.9% to 1.8% ± 1.0% (P < 0.05) in the intervention group compared with that in the controls. Conclusions: A simple tailored counseling was able to reduce muscle inactivity time by 33 min, which was reallocated to 21 min of light muscle activity. During work time, average EMG amplitude increased by 13%, reaching an average of 1.8% of EMGMVC. If maintained, this observed short-term effect may have health-benefiting consequences.peerReviewe

Example EMG data from laboratory and field measurements.

<p>Examples of averaged EMG data of left quadriceps femoris from one subject. Part A shows from the laboratory measurement session MVC of knee extension, lying down, standing still and squatting. Part B shows EMG activity during the entire day. Part C shows zoomed areas from daily EMG data (thick vertical lines show which parts of the data are zoomed). Horizontal lines represent baseline and 100% of EMG_MVC.</p

Basic characteristics of the subjects.

<p>Significant difference between genders are expressed as</p>**<p>p<0.01;</p>***<p>p<0.001.</p

Analysis of burst characteristics and muscle activities.

<p>Schematic drawing depicting analysis of burst amplitude, duration, inactivity periods and differentiation to light, moderate and vigorous muscle activities. The thresholds for inactivity, light, moderate and vigorous activities were determined individually (see text).</p

Inactivity times during normal daily life based on different thresholds.

<p>The first row represents results using individually determined threshold below standing activity (mean of four muscle groups) that is compared to the absolute % levels of each individual's EMG amplitude during maximal voluntary contraction (EMG_MVC).</p