0000000000123022
AUTHOR
Markus D. Jakobsen
showing 16 related works from this author
Progression of core stability exercises based on the extent of muscle activity
2017
OBJECTIVE: The aim of this cross-sectional study was to evaluate a variety of isometric plank exercises.DESIGN: Twenty university students performed the following eight different variants of plank exercises in random order and with 1-min rest intervals: stable prone plank, suspended prone plank, stable roll-out plank, suspended roll-out plank, unilateral stable prone plank, unilateral suspended prone plank, stable lateral plank, and suspended lateral plank. Surface electromyography signals were recorded for the upper rectus abdominis, lower rectus abdominis, external oblique, lumbar erector spinae, and normalized to the maximum voluntary isometric contraction.RESULTS: The suspended prone pl…
Association between Neck/Shoulder Pain and Trapezius Muscle Tenderness in Office Workers
2014
Background. Neck/shoulder pain is a common musculoskeletal disorder among adults. The pain is often assumed to be related to muscular tenderness rather than serious chronic disease. Aim. To determine the association between neck/shoulder pain intensity and trapezius muscle tenderness in office workers. Methods. 653 employees from two large office workplaces in Copenhagen, Denmark, replied to a questionnaire on health and working conditions (mean: age 43 years, body mass index 24 kg·m−2, computer use 90% of work time, 73% women). Respondents rated intensity of neck/shoulder pain during the previous three months on a scale of 0–10 and palpable tenderness of the upper trapezius muscle on a sca…
Knee Extensor Muscle Strength Is More Important Than Postural Balance for Stair-Climbing Ability in Elderly Patients with Severe Knee Osteoarthritis.
2021
Knee osteoarthritis is a chronic joint disease which damages articular cartilage. In its severe stages, it results in impairments in balance and muscle strength loss, which affect daily life activities such as walking or climbing stairs. This study sought to investigate associated factors with stair-climbing ability in this population, with special interest in measuring the relevance of postural balance for this task. Forty-four patients scheduled to undergo unilateral total knee arthroplasty were assessed. Timed up and go test, stair ascent–descent test, three different isometric strength tests (knee flexion, knee extension and hip abduction), active knee extension and flexion range of mov…
Electromyographic comparison of conventional machine strength training versus bodyweight exercises in patients with chronic stroke
2017
OBJECTIVE: To investigate whether bodyweight exercises can induce comparable levels of muscle activity as conventional machine exercises in chronic stroke patients.METHODS: Eighteen patients performed three repetitions of bilateral- and unilateral machine leg press and the bodyweight exercises chair rise and hip thrust. Surface electromyography (EMG) was recorded from 10 lower extremity muscles and normalized to maximal EMG (nEMG) of the non-paretic leg.RESULTS: For the paretic leg, the bodyweight exercises showed comparable levels of nEMG in 6 out of 10 muscles compared with the bilateral leg press. Vastus lateralis nEMG was higher during bilateral leg press compared with hip thrust (38% […
Attentional Focus and Grip Width Influences on Bench Press Resistance Training.
2018
This study evaluated the influence of different attentional foci for varied grip widths in the bench press. Eighteen resistance-trained men were familiarized with the procedure and performed a one-repetition maximum (1RM) test during Session 1. In Session 2, they used three different standardized grip widths (100%, 150%, and 200% of biacromial width distance) in random order at 50% of 1RM while also engaged in three different attention focus conditions (external focus on the bench press, internal focus on pectoralis major muscles, and internal focus on triceps brachii muscles). Surface electromyography (EMG) signals were recorded from the triceps brachii and pectoralis major, and peak EMG …
Influence of different attentional focus on EMG amplitude and contraction duration during the bench press at different speeds
2018
The purpose of this study was to investigate whether using different focus affects electromyographic (EMG) amplitude and contraction duration during bench press performed at explosive and controlled speeds. Eighteen young male individuals were familiarized with the procedure and performed the one-maximum repetition (1RM) test in the first session. In the second session, participants performed the bench press exercise at 50% of the 1RM with 3 different attentional focuses (regular focus on moving the load vs contracting the pectoralis vs contracting the triceps) at 2 speed conditions (controlled vs maximal speed). During the controlled speed condition, focusing on using either the pectoralis…
Acute Effect of Topical Menthol on Chronic Pain in Slaughterhouse Workers with Carpal Tunnel Syndrome: Triple-Blind, Randomized Placebo-Controlled Tr…
2014
Topical menthol gels are classified “topical analgesics” and are claimed to relieve minor aches and pains of the musculoskeletal system. In this study we investigate the acute effect of topical menthol on carpal tunnel syndrome (CTS). We screened 645 slaughterhouse workers and recruited 10 participants with CTS and chronic pain of the arm/hand who were randomly distributed into two groups to receive topical menthol (Biofreeze) or placebo (gel with a menthol scent) during the working day and 48 hours later the other treatment (crossover design). Participants rated arm/hand pain intensity during the last hour of work (scale 0–10) immediately before 1, 2, and 3 hours after application. Further…
Core Muscle Activity, Exercise Preference, and Perceived Exertion during Core Exercise with Elastic Resistance versus Machine
2015
Objectives. To investigate core muscle activity, exercise preferences, and perceived exertion during two selected core exercises performed with elastic resistance versus a conventional training machine.Methods. 17 untrained men aged 26–67 years participated in surface electromyography (EMG) measurements of five core muscles during torso-twists performed from left to right with elastic resistance and in the machine, respectively. The order of the exercises was randomized and each exercise consisted of 3 repetitions performed at a 10 RM load. EMG amplitude was normalized (nEMG) to maximum voluntary isometric contraction (MVC).Results. A higher right erector spinae activity in the elastic exer…
Postural control and physiological responses to a simulated match in U-20 judo competitors
2018
The aim was to evaluate the effects of judo combat on the athletes’ postural control (PC) and physiological loading before, during and after a simulated match. Seventeen under-20 regional and national level athletes completed one modified 7-min match. At baseline, during the combat (3rd and 7th minutes) and 2-min post-match centre of pressure (CoP) parameters were assessed. Heart rate (HR), blood lactate (BLa) and rating of perceived exertion (RPE) and local RPE (LRPE) were collected. Significant increments were observed in CoP mean positioning and velocity at 3rd and 7th minutes, but the CoP deviation in both axes was unaffected. HR and BLa were elevated at 3rd and 7th minutes, and they re…
Focusing on Increasing Velocity during Heavy Resistance Knee Flexion Exercise Boosts Hamstring Muscle Activity in Chronic Stroke Patients
2016
Background. Muscle strength is markedly reduced in stroke patients, which has negative implications for functional capacity and work ability. Different types of feedback during strength training exercises may alter neuromuscular activity and functional gains.Objective. To compare levels of muscle activity during conditions of blindfolding and intended high contraction speed with a normal condition of high-intensity knee flexions.Methods. Eighteen patients performed unilateral machine knee flexions with a 10-repetition maximum load. Surface electromyography (EMG) was recorded from the quadrics and hamstring muscles and normalized to maximal EMG (nEMG) of the nonparetic limb.Results. For the …
Electromyographic Effect of Using Different Attentional Foci During the Front Plank Exercise
2018
Objective The aim of this cross-sectional study was to examine whether an internal focus on different core muscles during the isometric prone plank exercise increased muscle activity. Design Twenty university students performed the following five different conditions: regular prone plank (external focus) and prone plank with an internal focus on different muscles. Surface electromyography signals were recorded for the upper rectus abdominis, lower rectus abdominis, external oblique, and lumbar erector spinae. Results For the upper rectus abdominis, an internal focus on using any muscle increased activity. For the lower rectus abdominis, internal focus on any muscle except the lumbar erector…
Trunk muscle activity during different variations of the supine plank exercise.
2017
BACKGROUND: Exercises providing neuromuscular challenges of the spinal muscles are desired for core stability, which is important for workers with heavy manual labour as well as people recovering from back pain.PURPOSE: This study evaluated whether using a suspended modality increases trunk muscle activity during unilateral or bilateral isometric supine planks.DESIGN: Cross-sectional.METHODS: Twenty university students participated in this cross-sectional study. Each subject performed four different conditions: bilateral stable supine plank, unilateral stable supine plank, bilateral suspended supine plank and unilateral suspended supine plank. Surface electromyography (EMG) signals were rec…
Electromyographic comparison of elastic resistance and machine exercises for high-intensity strength training in patients with chronic stroke
2016
To investigate whether elastic resistance training can induce comparable levels of muscle activity as conventional machine training in patients with chronic stroke.Comparative study.Outpatient rehabilitation facility.Stroke patients (N=18) with hemiparesis (mean age, 57 ± 8y).Patients performed 3 consecutive repetitions at 10 repetition maximum of unilateral knee extension and flexion using elastic resistance and conventional machine training.Surface electromyography was measured in vastus lateralis, vastus medialis, biceps femoris, and semitendinosus and was normalized to maximal electromyography (% of max) of the nonparetic leg.In the paretic leg, agonist muscle activity ranged from 18% t…
Muscle Activity During Unilateral vs. Bilateral Battle Rope Exercises.
2015
High training intensity is important for efficient strength gains. Although battle rope training is metabolically demanding, no studies have quantified intensity of muscle activity during this type of training. This study analyzes muscle activity during unilateral alternating waves vs. bilateral waves of battle rope training. Twenty-one volunteers participated in a repeated-measures study on 2 different occasions. Surface electromyographic signals were recorded from the anterior deltoid (AD), external oblique (OBLIQ), lumbar erector spinae (LUMB), and gluteus medius (GM) during bilateral waves and unilateral waves and were normalized to the maximum voluntary isometric contraction (MVIC). Re…
Dose-response association between leisure time physical activity and work ability:Cross-sectional study among 3000 workers
2015
INTRODUCTION: Regular physical activity is important for longevity and health, but knowledge about the optimal dose of physical activity for maintaining good work ability is unknown. This study investigates the association between intensity and duration of physical activity during leisure time and work ability in relation to physical demands of the job.METHODS: From the 2010 round of the Danish Work Environment Cohort Study, currently employed wage earners with physically demanding work (n = 2952) replied to questions about work, lifestyle and health. Excellent (100 points), very good (75 points), good (50 points), fair (25 points) and poor (0 points) work ability in relation to the physica…
Hand strengthening exercises in chronic stroke patients:Dose-response evaluation using electromyography
2016
Abstract Study Design Cross-sectional. Purpose of the Study This study evaluates finger flexion and extension strengthening exercises using elastic resistance in chronic stroke patients. Methods Eighteen stroke patients (mean age: 56.8 ± 7.6 years) with hemiparesis performed 3 consecutive repetitions of finger flexion and extension, using 3 different elastic resistance levels (easy, moderate, and hard). Surface electromyography was recorded from the flexor digitorum superficialis (FDS) and extensor digitorum (ED) muscles and normalized to the maximal electromyography of the non-paretic arm. Results Maximal grip strength was 39.2 (standard deviation: 12.5) and 7.8 kg (standard deviation: 9.4…