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Neuromuscular electrical stimulation (NMES) of the quadriceps (Q) may increase venous blood flow to reduce the risk of venous thromboembolism. This study assessed whether Q-NMES pants could increase peak venous velocity (PVV) in the femoral vein using Doppler ultrasound and minimize discomfort. On 15 healthy subjects, Q-NMES using textile electrodes integrated in pants was applied with increasing intensity (mA) until the first visible muscle contraction [measurement level (ML)-I] and with an additional increase of six NMES levels (ML II). Discomfort using a numeric rating scale (NRS, 0–10) and PVV were used to assess different NMES parameters: frequency (1, 36, 66 Hz), ramp-up/-down time (RUD) (0, 1 s), plateau time (1.5, 4, and 6 s), and on:off duty cycle (1:1, 1:2, 1:3, 1:4). Q-NMES pants significantly increased PVV from baseline with 93% at ML I and 173% at ML II. Frequencies 36 Hz and 66 Hz and no RUD resulted in significantly higher PVV at both MLs compared to 1 Hz and 1 s RUD, respectively. Plateau time, and duty cycle did not significantly change PVV. Discomfort was only significantly higher with increasing intensity and frequency. Q-NMES pants produces intensity- dependent 2−3-fold increases of venous blood flow with minimal discomfort. The superior NMES parameters were a fre- quency of 36 Hz, 0 s RUD, and intensity at ML II. Textile-based NMES wearables are promising for non-episodic venous thromboembolism prevention.

Background: Neuromuscular electrical stimulation (NMES) may prevent muscle atrophy, accelerate rehabilitation and enhance blood circulation. Yet, one major drawback is that patient compliance is impeded by the discomfort experienced. It is well-known that the size and placement of electrodes affect the comfort and effect during high-intensity NMES. However, during low-intensity NMES the effects of electrode size/placement are mostly unknown. Therefore, the purpose of this study was to investigate how electrode size and pragmatic placement affect comfort and effect of low-intensity NMES in the thigh and gluteal muscles. Methods: On 15 healthy participants, NMES-intensity (mA) was increased until visible muscle contraction, applied with three electrode sizes (2 × 2 cm, 5 × 5 cm, 5 × 9 cm), in three different configurations on quadriceps and hamstrings (short-transverse (ST), long-transverse (LT), longitudinal (L)) and two configurations on gluteus maximus (short-longitudinal (SL) and long-longitudinal (LL)). Current-density (mA/cm2) required for contraction was calculated for each electrode size. Comfort was assessed with a numerical rating scale (NRS, 0-10). Significance was set to p < 0.05 and values were expressed as median (inter-quartile range). Results: On quadriceps the LT-placement exhibited significantly better comfort and lower current intensity than the ST- and L-placements. On hamstrings the L-placement resulted in the best comfort together with the lowest intensity. On gluteus maximus the LL-placement demonstrated better comfort and required less intensity than SL-placement. On all muscles, the 5 × 5 cm and 5 × 9 cm electrodes were significantly more comfortable and required less current-density for contraction than the 2 × 2 cm electrode. Conclusion: During low-intensity NMES-treatment, an optimized electrode size and practical placement on each individual muscle of quadriceps, hamstrings and gluteals is crucial for comfort and intensity needed for muscl

Physical inactivity and immobilization have emerged as major health issues. Neuromuscular electrical stimulation (NMES) is a potential treatment to prevent the negative effects of physical inactivity, such as muscle atrophy and poor venous circulation. However, current NMES application is limited by poor compliance. Thus, the overarching aim of this thesis was to improve the efficacy of NMES targeting compliance by developing wearable NMES-pants. Development and testing of the NMES-pants on healthy, voluntary participants explored the effects on comfort, global muscle mRNA-expression, venous hemodynamics and blood coagulation. To optimize electrode dimensions and positioning within the NMES-pants, the intensity (mA) needed for a visible muscle contraction (ML I) and comfort during NMES when applied with different electrode sizes and placements on the quadriceps (Q), hamstrings (H), and gluteus (G) muscles were tested. The NMES-pants were then created based on the combination of electrode size and placement that provided the best comfort and that required the lowest current intensity for ML I. Subsequently, the textile electrodes in the NMES-pants were compared to commercial self-adhesive electrodes, by investigating the knee extensor force production created with NMES measured in an isokinetic dynamometer. We demonstrated that a contraction at 20% of the participant’s maximal voluntary contraction (MVC) could be reached at an acceptable level of discomfort with both methods. A large inter-individual variation in regards of comfort, intensity required, and force production was demonstrated, highlighting the importance of individually adjusted NMES for optimal compliance. To further investigate the NMES-pants, the effects of Q-NMES on muscle activation were assessed by examining vastus lateralis muscle gene expression using RNA-sequencing before and three hours after a 30-minute Q-NMES-pants session and/or regular exercise. The NMES-intensity was set to 20% of each pa

Aim: The influence on acute skeletal muscle transcriptomics of neuromuscular electrical stimulation (NMES), as compared to established exercises, is poorly understood. We aimed to investigate the effects on global mRNA-expression in the quadriceps muscle early after a single NMES-session, compared to the effects of voluntary knee extension exercise (EX), and to explore the discomfort level. Methods: Global vastus lateralis muscle gene expression was assessed (RNA-sequencing) in 30 healthy participants, before and 3h after a 30-min session of NMES and/or EX. The NMES-treatment was applied using textile electrodes integrated in pants and set to 20% of each participant's pre-tested MVC mean (±SD) 200 (±80) Nm. Discomfort was assessed using Visual Analogue Scale (VAS, 0–10). The EX-protocol was performed at 80% of 1-repetition-maximum. Results: NMES at 20% of MVC resulted in VAS below 4 and induced 4448 differentially expressed genes (DEGs) with 80%-overlap of the 2571 DEGs of EX. Genes well-known to be up-regulated following exercise, for example, PPARGC1A, ABRA, VEGFA, and GDNF, were also up-regulated by NMES. Gene set enrichment analysis demonstrated many common pathways after EX and NMES. Also, some pathways were exclusive to either EX, for example, muscle tissue proliferation, or to NMES, for example, neurite outgrowth and connective tissue proliferation. Conclusion: A 30-min NMES-session at 20% of MVC with NMES-pants, which can be applied with an acceptable level of discomfort, induces over 4000 DEGs, of which 80%-overlap with DEGs of EX. NMES can induce exercise-like molecular effects, that potentially can lead to health and performance benefits in individuals who are unable to perform resistance exercise.

Purpose: To investigate whether Neuromuscular Electrical Stimulation (NMES) simultaneously applied on the quadriceps (Q) and gluteal (G) muscles, as compared to single Q-stimulation alters the knee extensor force production and discomfort. Methods: A total of 11 healthy participants (6 females), with normal weight and age between 19 and 54 years were included. The unilateral, isometric maximal voluntary contraction (MVC) was assessed for each participant in an isokinetic dynamometer (Biodex, system 3). NMES was, in a randomized order, applied only on the Q-muscle and on the Q- and G-muscles (QG) simultaneously. NMES-intensity was increased stepwise until the maximal tolerable level was reached regarding discomfort, graded according to the visual analogue scale (VAS). VAS and the % of MVC produced by NMES, were registered for each level, expressed as median (inter-quartile range). Results: The maximum tolerated NMES-intensity applied on Q compared to QG resulted in equally high discomfort, 8.0 (6.0–9.0) vs 8.0 (6.3–9.0), and in equivalent knee extensor force production, 36.7 (29.9–47.5) and 36.2 (28.9–49.3), respectively, in % of MVC. At 20% of MVC, NMES applied on Q compared to QG resulted in equal acceptable discomfort, 3.0 (2.0–4.5) vs 3.0 (3–5.5), and comparable intensity levels, 41.5 (38.0–45.8) vs 43.5 (37.0–48.8), respectively. Conclusions: Simultaneous QG-NMES, as compared to single Q-NMES, does not seem to affect the knee extensor force production or discomfort. Q-NMES, without voluntary muscle contraction, can with an acceptable level of discomfort result in at least 20% of MVC.

Denna studies syfte var att undersöka vilka uppfattningar som lärare har beträffande begreppet lärande i samband med laborationer i den naturvetenskapliga undervisningen. Med ordet uppfattning menades ett antagande om något som en lärare var övertygad om eller tog för givet förhöll sig på ett visst sätt. För att få tillgång till lärares uppfattningar genomfördes idetta arbete sex intervjuer med lärare. Genom en kvalitativ fenomenografisk analys av dessa intervjuer har jag kategoriserat de uppfattningar av lärande som ligger till grund för lärares undervisning. I bakgrunden redogör jag för olika bakomliggande faktorer som kan ha påverkat lärares uppfattningar. Resultatet visar att lärarnas uppfattningar kan delas in i tre kategorier: Man lär sig genom att göra. Man lär sig genom att utgå från tidigare kunskaper. Man lär sig genom att diskutera.