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Purpose: Numerous daily tasks such as walking and rising from a chair involve bilateral lower limb movements. During such tasks, lower extremity function (LEF) may be compromised among older adults. LEF may be further impaired due to high degrees of between-limb asymmetry. The present study investigated the prevalence of between-limb asymmetry in muscle mass, strength, and power in a cohort of healthy older adults and examined the influence of between-limb asymmetry on LEF., Methods: Two hundred and eight healthy older adults (mean age 70.2 ± 3.9 years) were tested for LEF (400 m walking and 30-seconds chair stand). Furthermore, maximal isometric and dynamic knee extensor strength, leg extensor power, and lower limb lean tissue mass (LTM) were obtained unilaterally., Results: Mean between-limb asymmetry in maximal muscle strength and power ranged between 10% and 13%, whereas LTM asymmetry was 3 ± 2.3%. Asymmetry in dynamic knee extensor strength was larger for women compared with men (15.0 ± 11.8% vs 11.1 ± 9.5%; P = .005) Leg strength and power were positively correlated with LEF (r 2  = .43-.46, P < .001). The weakest leg was not a stronger predictor of LEF than the strongest leg. Between-limb asymmetry in LTM and isometric strength was negatively associated with LEF (LTM; r 2  = .12, P = .005, isometric peak torque; r 2  = 0.40, P = .03.) but dynamic strength and power were not., Conclusion: The present study supports the notion that in order to improve or maintain LEF, healthy older adults should participate in training interventions that increase muscle strength and power, whereas the effects of reducing between-limb asymmetry in these parameters might be of less importance., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The aim of this study is to identify factors associated with musculo-skeletal pain reduction during workplace-based or home-based physical exercise interventions among healthcare workers. Two hundred female healthcare workers (age: 42.0, BMI: 24.1, average pain intensity: 3.1 on a scale of 0-10) from three hospitals participated. Participants were randomly allocated at the cluster level (18 departments) to 10 weeks of (i) workplace physical exercise (WORK) performed in groups during working hours for 5 × 10 minutes per week and up to five group-based coaching sessions on motivation for regular physical exercise, or (ii) home-based physical exercise (HOME) performed alone during leisure-time for 5 × 10 minutes per week. Linear mixed models accounting for cluster identified factors affecting pain reduction. On average 2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions were performed per week in WORK and HOME, respectively. The multi-adjusted analysis showed a significant effect on pain reduction of both training adherence (P=.04) and intervention group (P=.04) with participants in WORK experiencing greater reductions compared with HOME. Obesity at baseline was associated with better outcome. Leisure-time exercise, daily patient transfer, age, and chronic pain did not affect the changes in pain. In conclusion, even when adjusted for training adherence, performing physical exercise at the workplace is more effective than home-based exercise in reducing musculo-skeletal pain in healthcare workers. Noteworthy, obese individuals may especially benefit from physical exercise interventions targeting musculo-skeletal pain., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Valid and reliable measurements of muscle strength are important in sport medicine. This study assesses concurrent validity and intrarater reliability (test-retest reliability) of elastic resistance bands for measuring shoulder muscle strength. Altogether, 50 healthy adults [mean age 36.0 (SD: 11.6), 29 women and 21 men] participated in testing and retesting 1-2 weeks later. The maximal elastic resistance (TheraBand) that each participant could hold for 3 s during standing bilateral shoulder abduction to 90° was converted into torque and validated against gold standard maximal voluntary isometric contraction (MVC) (Vishay force transducer) performed unilaterally while lying supine. The intrarater reliability of both tests were high; for the MVC and elastic band test, respectively, ICC(3,1) was 0.98 (95% CI: 0.97-0.99) and 0.99 (95% CI: 0.98-1.00), and measurement error was 4.8% (95% CI: 3.7-5.9) and 4.7% (95% CI: 3.1-6.2). For concurrent validity, ICC(3,1) was 0.96 (95% CI: 0.95-0.98) and measurement error was 8.1% (95% CI: 6.6-9.6), and the elastic band test explained 93% of the variance in the MVC test. However, the elastic band test produced systematically lower torque values than the MVC [56.5 (SD: 26.8) vs 66.5 (SD: 25.5) Nm, P < 0.01]. In conclusion, the test for shoulder muscle strength using elastic resistance bands has excellent validity and reliability, but produces systematically lower torque values than MVC. The reason for the lower torque values may be that the elastic band test has an initial concentric phase and is performed bilaterally and standing upright., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Therapists commonly use elastic bands in resistance exercises during rehabilitation of smaller muscles, such as in the shoulder. However, the effectiveness has not yet been investigated for larger muscle groups. This study investigates muscle activity during lower extremity exercises. Electromyographic (EMG) activity of 10 muscles was measured in 24 women and 18 men during lunges with elastic resistance, lunges with dumbbells, and unilateral leg press in machine using 10 repetition maximum loadings, and normalized to maximal voluntary isometric contraction EMG. Lunges with dumbbells and leg press showed higher activity than lunges with elastic resistance for the vasti and rectus femoris (P < 0.01), whereas lunges with elastic resistance showed higher activity of gluteus maximus, hamstrings, and erector spinae (P < 0.01). Gender, age, and pain in the knees and hip did not influence these findings. However, pain in the lower back decreased muscular activity of the gluteus maximus and vastus medialis (P < 0.01). Lunges with elastic resistance induce high levels of muscle activity in all the large muscle groups at the hip, knee, and back. Importantly, the efficiency of these exercises was equally high regardless of gender, age, and pain in the knees and hip, whereas pain in the lower back led to altered activation strategies., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The effects of 16 weeks of football or strength training on performance and functional ability were investigated in 26 (68.2 ± 3.2 years) untrained men randomized into a football (FG; n = 9), a strength training (ST; n = 9), or a control group (CO; n = 8). FG and ST trained 1.6 ± 0.1 and 1.5 ± 0.1 times per week, respectively, with higher (P < 0.05) average heart rate (HR) (∼140 vs 100 bpm) and time >90%HRmax (17 vs 0%) in FG than ST, and lower (P < 0.05) peak blood lactate in FG than ST (7.2 ± 0.9 vs 10.5 ± 0.6 mmol/L). After the intervention period (IP), VO₂ max (15%; P < 0.001), cycle time to exhaustion (7%; P < 0.05), and Yo-Yo Intermittent Endurance Level 1 performance (43%; P < 0.01) were improved in FG, but unchanged in ST and CO. HR during walking was 12% and 10% lower (P < 0.05) in FG and ST, respectively, after IP. After IP, HR and blood lactate during jogging were 7% (P < 0.05) and 30% lower (P < 0.001) in FG, but unchanged in ST and CO. Sit-to-stand performance was improved (P < 0.01) by 29% in FG and 26% in ST, but not in CO. In conclusion, football and strength training for old men improves functional ability and physiological response to submaximal exercise, while football additionally elevates maximal aerobic fitness and exhaustive exercise performance., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The present study investigated whether elderly subjects exposed to lifelong football training have better rapid muscle force characteristics, body composition and postural stability in comparison with untrained elderly. Ten elderly men exposed to lifelong football training (FTE; 69.6 +/- 1.4 years) and eight age-matched untrained elderly men (UE; 70.5 +/- 1.0 years) were studied and 49 untrained young men (UY; 32.4 +/- 0.9 years) served as a reference group. FTE showed an elevated rate of force development (RFD) and impulse at 0-30, 100 and 200 ms (relative RFD at 1/6 MVC: 567 +/- 39 vs 353 +/- 42% MVC/s), higher total lean body mass (56.9 +/- 0.8 vs 52.7 +/- 2.2 kg) and better postural stability (Flamingo test: 15 +/- 1 vs 33 +/- 2 falls) compared with UE (P<0.05), with no difference between FTE and UY. The proportion of type IIA fibers was higher and the area percentage of type IIX fibers was lower in FTE than in UE (P<0.05). Rapid muscle force characteristics and postural stability were consistently higher in elderly subjects exposed to lifelong football training, providing an enhanced ability to counteract unexpected perturbations in postural balance. The superior RFD and balance in elderly footballers were of such a magnitude that no deficit could be observed when compared with young untrained individuals.

We examined long-term musculoskeletal and cardiac adaptations elicited by recreational football (FG, n=9) and running (RG, n=10) in untrained premenopausal women in comparison with a control group (CG, n=9). Training was performed for 16 months ( approximately 2 weekly 1-h sessions). For FG, right and left ventricular end-diastolic diameters were increased by 24% and 5% (P<0.05), respectively, after 16 months. Right ventricular systolic function measured by tricuspid annular plane systolic excursion (TAPSE) increased (P<0.05) in FG after 4 months and further (P<0.05) after 16 months (15% and 32%, respectively). In RG and CG, cardiac structure, E/A and TAPSE remained unchanged. For FG, whole-body bone mineral density (BMD) was 2.3% and 1.3% higher (P<0.05) after 16 months, than after 4 and 0 months, respectively, with no changes for RG and CG. FG demonstrated substantial improvements (P<0.05) in fast (27% and 16%) and slow (16% and 17%) eccentric muscle strength and rapid force capacity (Imp30ms: 66% and 65%) after 16 months compared with 4 and 0 months, with RG improving Imp30ms by 64% and 46%. In conclusion, long-term recreational football improved muscle function, postural balance and BMD in adult women with a potential favorable influence on the risk of falls and fractures. Moreover, football training induced consistent cardiac adaptations, which may have implications for long-term cardiovascular health.

The present intervention was designed to investigate whether a 14-week period of regular recreational association football (F) or endurance running (R) has an effect on the risk of falls and bone fractures due to gains in muscle function and volumetric bone mineral density (vBMD). Fifty healthy untrained Danish premenopausal women were randomized into two training groups (F and R) that trained 1.8+/-0.3 (+/-SD) and 1.9+/-0.3 h/week, respectively, and these groups were compared with an inactive control group (C). Jumping and dynamic muscle strength were tested and tibial vBMD was measured using peripheral quantitative computed tomography. Total vBMD in left and right tibia increased by 2.6+/-2.3% and 2.1+/-1.8% (P<0.005), respectively, in F and by 0.7+/-1.3% (P=0.05) and 1.1+/-1.5% (P<0.01), respectively, in R without any significant changes in C. Similar results were found for trabecular vBMD. In F, peak jump power increased by 3+/-6% (P<0.05), and hamstring strength during fast (240 degrees /s) and slow (30 degrees /s) contractions increased by 11+/-25% and 9+/-21%, respectively, (P<0.05) without any significant changes in R or C. In conclusion, 14 weeks of regular recreational football improved peak jump power, maximal hamstring strength and vBMD in the distal tibia, suggesting a decreased fracture risk due to stronger bones and a reduced risk of falling.

We examined whether improvements in the performance and health profile of an intensive 12-week football intervention could be maintained with a reduced training frequency. Seventeen healthy untrained males completed the study. Ten subjects trained 2.4 times/week for 12 weeks and another 52 weeks with 1.3 sessions/week [football group (FG)] and seven subjects acted as controls [control group (CG)]. For FG, fat mass (3.2 kg) and systolic blood pressure (8 mmHg) were lower (P<0.05) after 64 than 0 weeks, and VO(2max) (8%) and Yo-Yo intermittent endurance level 2 test performance (49%) were higher (P<0.05), with no difference between 64 and 12 weeks. After 64 weeks, quadriceps muscle mass (11%), mean fiber area (10%) and citrate synthase activity (18%) were higher (P<0.05) than those at 0 weeks. Leg bone mass (3.5%) and density (2.0%) were higher (P<0.05) after 64 than 0 weeks, but not different between 12 and 0 weeks. Plantar jump force (17-18%), 30-m sprinting velocity (1.3-3.0%) and muscle glycogen concentration (19-21%) were higher (P<0.05) and blood lactate during submaximal exercise was lower (27-72%, P<0.05) after 64 than after 12 and 0 weeks. The above-mentioned variables were unaltered for CG. In conclusion, positive adaptations in cardiovascular fitness obtained over 12 weeks of regular recreational football training can be maintained over a 1-year period with a reduced training frequency, with further development in musculo-skeletal fitness.