[Show abstract][Hide abstract] ABSTRACT: Objectives
. The present study investigates the effect of workplace- versus home-based physical exercise on muscle reflex response to sudden trunk perturbation among healthcare workers.
. Two hundred female healthcare workers (age: 42 [SD 11], BMI: 24 [SD 4], and pain intensity: 3.1 [SD 2.2] on a scale of 0–10) from 18 departments at three hospitals were randomized at the cluster level to 10 weeks of (1) workplace physical exercise (WORK) performed in groups during working hours for 5
10 minutes per week and up to 5 group-based coaching sessions on motivation for regular physical exercise, or (2) home-based physical exercise (HOME) performed during leisure time for 5
10 minutes per week. Mechanical and neuromuscular (EMG) response to randomly assigned unloading and loading trunk perturbations and questions of fear avoidance were assessed at baseline and 10-week follow-up.
group by time
interaction for the mechanical trunk response and EMG latency time was seen following the ten weeks (
= 0.17–0.75). However, both groups demonstrated within-group changes (
) in stopping time during the loading and unloading perturbation and in stopping distance during the loading perturbation. Furthermore, EMG preactivation of the erector spinae and fear avoidance were reduced more following WORK than HOME (95% CI −2.7–−0.7 (
) and −0.14 (−0.30 to 0.02) (
)), respectively. WORK and HOME performed 2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions per week, respectively.
. Although training adherence was higher following WORK compared to HOME this additional training volume did not lead to significant between-group differences in the responses to sudden trunk perturbations. However, WORK led to reduced fear avoidance and reduced muscle preactivity prior to the perturbation onset, compared with HOME. This trial is registered with Clinicaltrials.gov (
[Show abstract][Hide abstract] ABSTRACT: Diabetic patients have an increased risk of foot ulcers, and glycation of collagen may increase tissue stiffness. We hypothesized that the level of glycemic control (glycation) may affect Achilles tendon stiffness, which can influence gait pattern. We therefore investigated the relationship between collagen glycation, Achilles tendon stiffness parameters and plantar pressure in poorly (n = 22) and well (n = 22) controlled diabetic patients, including healthy age matched (45-70 yrs) controls (n = 11). There were no differences in any of outcome parameters (collagen cross-linking or tendon stiffness) between patients with well-controlled and poorly controlled diabetes. The overall effect of diabetes was explored by collapsing the diabetes groups (DB) compared to the controls. Skin collagen cross-linking lysylpyridinoline (LP), hydroxylysylpyridinoline (HP), (136%, 80%, P < 0.01) and pentosidine concentrations (55%, P < 0.05) were markedly greater in DB. Furthermore, Achilles tendon material stiffness was higher in DB (54%, P < 0.01). Notably, DB also demonstrated higher forefoot/ rearfoot peak plantar pressure (PPP)-ratio (33%, P < 0.01). Overall, Achilles tendon material stiffness and skin connective tissue cross-linking were greater in diabetic patients compared to controls. The higher foot pressure indicates that material stiffness of tendon and other tissue (e.g skin and joint capsule) may influence on foot gait. The difference in foot pressure distribution may contribute to the development of foot ulcers in diabetic patients.
Journal of Applied Physiology 11/2015; DOI:10.1152/japplphysiol.00547.2015 · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Adolescent female football and handball players are among the athletes with the highest risk of sustaining anterior cruciate ligament (ACL) injuries.
This study evaluated the effects of evidence-based lower extremity injury prevention training on neuromuscular and biomechanical risk factors for non-contact ACL injury.
40 adolescent female football and handball players (15-16 years) were randomly allocated to a control group (CON, n=20) or neuromuscular training group (NMT, n=20). The NMT group performed an injury prevention programme as a warm-up before their usual training 3 times weekly for 12 weeks. The CON group completed their regular warm-up exercise programme before training. Players were tested while performing a side cutting movement at baseline and 12-week follow-up, using surface electromyography (EMG) and three-dimensional movement analysis. We calculated: (1) EMG amplitude from vastus lateralis (VL), semitendinosus (ST) and biceps femoris 10 ms prior to initial contact (IC) normalised to peak EMG amplitude recorded during maximal voluntary isometric contraction and (2) VL-ST EMG preactivity difference during the 10 ms prior to foot contact (primary outcome). We measured maximal knee joint valgus moment and knee valgus angle at IC.
There was a difference between groups at follow-up in VL-ST preactivity (43% between-group difference; 95% CI 32% to 55%). No between-group differences were observed for kinematic and kinetic variables.
A 12-week injury prevention programme in addition to training and match play in adolescent females altered the pattern of agonist-antagonist muscle preactivity during side cutting. This may represent a more ACL-protective motor strategy.
British Journal of Sports Medicine 09/2015; DOI:10.1136/bjsports-2015-094776 · 5.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study evaluates the between-day reliability of a newly developed trunk perturbation test and compares mechanical response during known and unknown conditions. Mechanical trunk response were measured in seventeen female subjects during unloading and loading perturbations of the abdomen (A: preloaded-abdomen condition) and low-back (B: preloaded-back condition). The loading perturbation increased the preload from 5.5 kg to a 10 kg pull on the trunk whereas the unloading perturbation decreased the pull from 5.5 kg to 0.1 kg. A sequence of loading (known), unloading (known) and randomized loading/unloading (unknown) perturbations were performed for A and B. Between-day reliability of stopping time, trunk displacement and velocity was quantified using intraclass correlation coefficients (ICCs). ICCs were good to excellent for all loading and unloading measures during the known (0.70 - 0.98) and unknown (0.64 - 0.94) perturbations of A and B. In general, larger trunk displacements were seen after the unknown perturbations compared with the known perturbation. The method may be used as a diagnostic tool for screening workers who are in risk of future work related low back injuries.
Journal of applied biomechanics 09/2015; DOI:10.1123/jab.2015-0120 · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising torque. Twenty healthy men were assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180°s-1. Maximal isometric knee extensor torque (MVC) and incremental RFD in successive 50 ms time-windows from the onset contraction were analysed in absolute terms (RFDINC) or when normalised relative to MVC (RFDREL). After eight weeks, TG demonstrated increases in MVC (28%), RFDINC (0-50 ms: 30%; 50-100 ms: 31%) and RFDREL (0-50 ms: 29%; 50-100 ms: 32%). Moreover, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL obtained at the early phase of rising joint torque.
European Journal of Sport Science 02/2015; DOI:10.1080/17461391.2015.1010593 · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Numerous studies has shown that regular physical exercise can reduce musculoskeletal pain, but the optimal setting to achieve high adherence and effectiveness remains unknown. This study investigated the effect of workplace versus home-based physical exercise on musculoskeletal pain among healthcare workers.
The randomized controlled trial (RCT) comprised 200 female healthcare workers from 18 departments at 3 hospitals. Participants were randomly allocated at the cluster level to ten weeks of: (i) workplace physical exercise (WORK) performed during working hours for 5×10 minutes per week and up to 5 group-based coaching sessions on motivation for regular physical exercise, or (ii) home-based physical exercise (HOME) performed during leisure time for 5×10 minutes per week. Both groups received ergonomic counseling on patient handling and use of lifting aides. Average pain intensity (0-10 scale) in the low back and neck/shoulder was the primary outcome.
Per week, 2.2 (SD 1.1) and 1.0 (SD 1.2) training sessions were performed in WORK and HOME groups, respectively. Pain intensity, back muscle strength and use of analgesics improved more following WORK than HOME (P<0.05). Between-group differences at follow-up (WORK versus HOME) was -0.7 points for pain intensity [95% confidence interval (95% CI) -1.0- -0.3], 5.5 Nm for back muscle strength (95% CI 2.0-9.0), and -0.4 days per week for use of analgesics (95% CI -0.7- -0.2). The effect size for between-group differences in pain intensity was small (Cohen's d=0.31).
Workplace physical exercise is more effective than home-based exercise in reducing musculoskeletal pain, increasing muscle strength and reducing the use of analgesics among healthcare workers.
Scandinavian Journal of Work, Environment & Health 01/2015; 41(2). DOI:10.5271/sjweh.3479 · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To determine the physical demands placed on female elite team handball players in relation to playing position and body anthropometry, female elite team handball primarily field players were monitored during match-play using video recording and subsequent computerized technical match analysis during five regular tournament match seasons. Technical match activities were distributed in 6 major types of playing actions (shots, breakthroughs, fast breaks, technical errors, defensive errors and tackles) and further divided into various subcategories (e.g., type of shot, hard or light tackles, claspings, screenings and blockings). Furthermore, anthropometric measurements were carried out.Each player had 28.3±11.0 (group means±SD) high-intense playing actions per match with a total effective playing time of 50.70±5.83 min. On average, each player made 2.8±2.6 fast breaks, gave 7.9±14.4 screenings, received 14.6±9.2 tackles in total and performed 7.7±3.7 shots while in offense, along with 3.5±3.8 blockings, 1.9±2.7 claspings and 6.2±3.8 hard tackles in defense. Mean body height, body mass and age in the Danish Premier Female Handball League were 175.4±6.1 cm, 69.5±6.5 kg and 25.4±3.7 years, respectively. Wing players were lighter (63.5±4.8 kg, p<0.001) and smaller (169.3±4.9 cm, p<0.001) than backcourt players (70.6±5.3 kg, 177.0±5.4 cm) and pivots (72.5±4.9 kg, 177.7±4.9 cm).In conclusion, the present match observations revealed that female elite team handball players during competitive games intermittently perform a high number of short-term, high-intense technical playing actions making modern female elite team handball a physically demanding team sport. No sign of technical fatigue were observed, since the amount of intense technical playing actions remained unchanged in the second half. Marked positional differences in the physical demands were demonstrated, with wing players performing more fast breaks and less physical confrontations than backcourt players and pivots. Body anthropometry differed substantially between different playing positions. Consequently, this should lead to an increase in physical training in modern female elite team handball directed at specific positions and individual physical capacity.
The Journal of Strength and Conditioning Research 10/2014; 29(4). DOI:10.1519/JSC.0000000000000735 · 2.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Associations between objective and subjective measures of knee function may facilitate rehabilitation in ACL-patients. Aim: The aim of this study is to investigate if a test-battery of functional and/or muscle outcomes are associated with Knee osteoarthritis outcome score (KOOS) subscales (Sport/Rec and QOL) in ACL-reconstructed patients. Methods: 23 hamstring auto-graft ACL-reconstructed men (mean age: 27.2 standard deviation 7.5 years, BMI: 25.4 standard deviation 3.2 time since surgery: 27 standard deviation 7 months) completed KOOS-questionnaire and an objective test-battery: (i) one-leg maximal jump for distance (OLJD), isometric maximal voluntary contraction (MVC) for (ii) knee extensors and (iii) flexors, and (iv) maximal counter movement jump (CMJ). Sagittal kinematic data were recorded during CMJ using a 6-camera Vicon MX system. Multilevel linear regression analysis was used to determine the strength of associations between KOOS parameters (Sport/Rec and QOL) that a priori were defined as dependent variables and 4 models of independent outcomes from the test-battery. Results: Moderate associations between OLJD and Sport/Rec (r(2) = 0.26, p < 0.01) and QOL (r(2) = 0.26, p < 0.01) were observed (Model 1). Adding knee extensor or flexor MVC to the analysis (Model 2) increased the strength of the associations (up to r(2) = 0.53, p < 0.01, and r(2) = 0.31, p = 0.02 for Sport/Rec and QOL, respectively). Adding both knee extensor and knee flexor MVC to the analysis (Model 3) did not improve the regression model and only minor increases were observed when including kinematic data of CMJ (Model 4). Conclusion: Moderate-to-large proportion (31-53%) of the variation in KOOS was explained by OLJD and MVC which may add to design effective future rehabilitation interventions for ACL-patients.
The Knee 10/2014; 21(6). DOI:10.1016/j.knee.2014.09.004 · 1.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Due to a high incidence of anterior cruciate ligament (ACL) re-injury in alpine ski racers, this study aims to assess functional asymmetry in the countermovement jump (CMJ), squat jump (SJ), and leg muscle mass in elite ski racers with and without anterior cruciate ligament reconstruction (ACL-R). Elite alpine skiers with ACL-R (n = 9; 26.2 ± 11.8 months post-op) and uninjured skiers (n = 9) participated in neuromuscular screening. Vertical ground reaction force during the CMJ and SJ was assessed using dual force plate methodology to obtain phase-specific bilateral asymmetry indices (AIs) for kinetic impulse (CMJ and SJ phase-specific kinetic impulse AI). Dual x-ray absorptiometry scanning was used to assess asymmetry in lower body muscle mass. Compared with controls, ACL-R skiers had increased AI in muscle mass (P < 0.001), kinetic impulse AI in the CMJ concentric phase (P < 0.05), and the final phase of the SJ (P < 0.05). Positive associations were observed between muscle mass and AI in the CMJ concentric phase (r = 0.57, P < 0.01) as well as in the late SJ phase (r = 0.66, P < 0.01). Future research is required to assess the role of the CMJ and SJ phase-specific kinetic impulse AI as a part of a multifaceted approach for improving outcome following ACL-R in elite ski racers.
Scandinavian Journal of Medicine and Science in Sports 10/2014; 25(3). DOI:10.1111/sms.12314 · 2.90 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Physical fitness and muscular strength are important performance parameters in Olympic sailing although their relative importance changes between classes. The Olympic format consists of eight yacht types combined into 10 so-called events with total 15 sailors (male and female) in a complete national Olympic delegation. The yachts have different requirements with respect to handling, and moreover, each sailor plays a specific role when sailing. Therefore physical demands remain heterogeneous for Olympic sailors. Previous studies have mainly examined sailors where 'hiking' (the task of leaning over the side of the yacht to increase righting moment) is the primary requirement. Other than the ability to sustain prolonged quasi-isometric contractions, hiking seems to require significant maximal muscle strength especially in knee extensors, hip flexors and abdominal and lower back muscles. Another group of studies has investigated boardsailing and provided evidence to show that windsurfing requires very high aerobic and anaerobic capacity. Although data exist on other types of sailors, the information is limited, and moreover the profile of the Olympic events has changed markedly over the last few years to involve more agile, fast and spectacular yachts. The change of events in Olympic sailing has likely added to physical requirements; however, data on sailors in the modern-type yachts are scarce. The present paper describes the recent developments in Olympic sailing with respect to yacht types, and reviews the existing knowledge on physical requirements in modern Olympic sailing. Finally, recommendations for future research in sailing are given.
European Journal of Sport Science 09/2014; 15(3):1-8. DOI:10.1080/17461391.2014.955130 · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Life-long regular endurance exercise is known to counteract the deterioration of cardiovascular and metabolic function and overall mortality. Yet it remains unknown if life-long regular endurance exercise can influence the connective tissue accumulation of advanced glycation endproducts (AGEs) that is associated with aging and lifestyle-related diseases. We therefore examined two groups of healthy elderly men: 15 master athletes (64 ± 4 years) who had been engaged in life-long endurance running and 12 old untrained (66 ± 4 years) together with two groups of healthy young men; ten young athletes matched for running distance (26 ± 4 years), and 12 young untrained (24 ± 3 years). AGE cross-links (pentosidine) of the patellar tendon were measured biochemically, and in the skin, it was assessed by a fluorometric method. In addition, we determined mechanical properties and microstructure of the patellar tendon. Life-long regular endurance runners (master athletes) had a 21 % lower AGE cross-link density compared to old untrained. Furthermore, both master athletes and young athletes displayed a thicker patellar tendon. These cross-sectional data suggest that life-long regular endurance running can partly counteract the aging process in connective tissue by reducing age-related accumulation of AGEs. This may not only benefit skin and tendon but also other long-lived protein tissues in the body. Furthermore, it appears that endurance running yields tendon tissue hypertrophy that may serve to lower the stress on the tendon and thereby reduce the risk of injury.
Journal of the American Aging Association 08/2014; 36(4):9665. DOI:10.1007/s11357-014-9665-9 · 3.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Modern team handball match-play imposes substantial physical and technical demands on elite players. However, only limited knowledge seems to exist about the specific working requirements in elite team handball. Thus, the purpose of the present study was to examine the physical demands imposed on male elite team handball players in relation to playing position and body anthropometry.Based on continuous video recording of individual players during elite team handball match-play (62 tournament games, ∼ 4 players per game), computerized technical match analysis was performed in male elite team handball players along with anthropometric measurements over a six season time span. Technical match activities were distributed in 6 major types of playing actions (shots, breakthroughs, fast breaks, tackles, technical errors and defense errors) and further divided into various subcategories (e.g. hard or light tackles, type of shot, clapings, screenings and blockings).Players showed 36.9±13.1 (group means±SD) high-intense technical playing actions per match with a mean total effective playing time of 53.85±5.87 min. In offense, each player performed 6.0±5.2 fast breaks, received 34.5±21.3 tackles in total and performed in defense 3.7±3.5 blockings and 3.9±3.0 claspings and 5.8±3.6 hard tackles. Wing players (84.5±5.8 kg, 184.9±5.7 cm) were less heavy and smaller (p<0.001) than backcourt players (94.7±7.1 kg, 191.9±5.4 cm) and pivots (99.4±6.2 kg, 194.8±3.6 cm).In conclusion, modern male elite team handball match-play is characterized by a high number of short-term, high-intense intermittent technical playing actions. Indications of technical fatigue were observed. Physical demands differed between playing positions with wing players performing more fast breaks and less physical confrontations with opponent players than backcourt players and pivots. Body anthropometry appeared to have an important influence on playing performance, since highly related to playing positions. The present observations suggest that male elite team handball players should implement more position-specific training regimens, while also focusing on anaerobic training and strength training.
The Journal of Strength and Conditioning Research 06/2014; 29(2). DOI:10.1519/JSC.0000000000000595 · 2.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim:
The aim of the present study was to examine differences in the physical demands imposed on male vs. female adult elite team handball players during match--play.
Male and female elite team handball players were monitored over a six and five season time span, respectively. Each player was evaluated during match--play by use of video recording and subsequent computerized locomotive and technical match analysis. Furthermore, physiological measurements during match--play, physical testing and anthropometric measurements were performed.
Female players (FP, n=82) covered a longer mean total distance per match (4693±333 m, group means±SD) compared to male players (MP, n=83, 3945±538 m) when playing full time (p<0.01). FP exercised at a greater relative workload (79.4 % of VO2--max) than MP (70.9 % of VO2--max, p<0.05), but performed less high--intense running per match (2.6 % of total distance covered) than MP (7.9 %, p<0.01). FP also spent less time standing still (10.8 % of total effective playing time) compared to MP (36.9 %, p<0.001) and showed fewer activity changes (663.8±99.7) compared to MP (1482.4±312.6, p<0.001). MP received more tackles in total in offence (34.5±21.3) and performed more tackles in total in defence (29.9±12.3) compared to FP (14.6±9.2, 20.7±9.7, p<0.05). Further, MP performed more high--intense technical playing actions per match (36.9±13.1) than FP (28.3±11.0, p<0.05). Mean body height and body mass differed between MP (189.6±5.8 cm, 91.7±7.5 kg) and FP (175.4±6.1 cm, 69.5±6.5 kg, p<0.001).
Substantial gender--specific differences in the physical demands in elite team handball were observed, with MP performing more high--intense, strength--related playing actions and high--intensity running than FP. Conversely, FP covered a greater total distance and demonstrated a higher relative workload than MP. The physical training of male and female elite team handball players should be designed to reflect these contrasting needs.
The Journal of sports medicine and physical fitness 06/2014; · 0.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The neuromuscular adaptations in response to muscle stretch training have not been clearly described. In the present study, changes in muscle (at fascicular and whole muscle levels) and tendon mechanics, muscle activity and spinal motoneuron excitability were examined during standardized plantar flexor stretches after 3 wk of twice-daily stretch training (4×30-s). No changes were observed in a non-exercising control group (N=9), however stretch training elicited a 19.9% increase in dorsiflexion range of motion (ROM) and 28% increase in passive joint moment at end ROM (N=12). Only a trend toward a decrease in passive plantar flexor moment during stretch (-9.9%, p=0.15) was observed and no changes in EMG amplitudes during or at end ROM were detected. Decreases in Hmax:Mmax (tibial nerve stimulation) were observed at plantar flexed (gastrocnemius medialis and soleus) and neutral (soleus only) joint angles, but not with the ankle dorsiflexed. Muscle and fascicle strain increased (12 vs. 23%) along with a decrease in muscle stiffness (-18%) during stretch to a constant target joint angle. Muscle length at end ROM increased (13%) without a change in fascicle length, fascicle rotation, tendon elongation or tendon stiffness following training. A lack of change in MVC moment and RFD at any joint angle was taken to indicate a lack of change in series compliance of the muscle-tendon unit. Thus, increases in end ROM were underpinned by increases in maximum tolerable passive joint moment ('stretch tolerance') and both muscle and fascicle elongation rather than changes in volitional muscle activation or motoneuron pool excitability.
Journal of Applied Physiology 06/2014; DOI:10.1152/japplphysiol.00204.2014 · 3.06 Impact Factor