Isokinetics and Exercise Science

Eccentric strength training changes muscle architecture but it is also an important factor for the prevention of injuries and their rehabilitation.

To determine the architectural adaptations of the semitendinosus (ST) after an eccentric strength training protocol with Nordic hamstring exercise (NHE), followed by a subsequent detraining period.

Twenty-three male individuals, aged 25.5 ± 3.3, completed an 8 week intervention, where the architectural characteristics of the ST were evaluated using a two-dimensional ultrasound before (pretest-week-1), after the training period (posttest-week-9) and at the end of the detraining period (retest-week-13).

The post-test scores indicated that eccentric strength training resulted in a significant increase in the fascicle length (FL) (t = ⁣ - 12.5, d = 3.53, P < 0.01) and muscle thickness (MT) (t = ⁣ - 9.69, d = 2.85, P < 0.01), whereas the pennation angle (PA) decreased significantly (t = 6.42, d = 1.76, P < 0.01). In retest, both FL (t = 9.7, d = 2.65, P < 0.01) and MT (t = 9.18, d = 2.65, P < 0.01) decreased significantly, whereas PA showed a significant increase (t = ⁣ - 5.39, d = 1.47, P < 0.01).

The NHE seems to generate adaptations in ST architecture, which, in addition, are also reversible after a detraining period. These results may have practical implications for injury prevention and rehabilitation programmes.

Assessment of physical fitness is a common and effective method for evaluating the health status of teenage students.

The present study was conducted to assess physical fitness in adolescents residing in Shanghai, and investigate the relationships among anthropometry, muscle fitness, and a 20-meter shuttle run test (20-m SRT).

A total of 449 middle school students (12–17 years old, 246 boys and 203 girls) from four different regions of Shanghai, China were included as study participants.

Multiple linear regression analyses indicate that upper extremity muscle strength and standing vertical jump were positively related to age and weight, while negatively related to gender, scapular skinfold, and calf skinfold. Strong positive correlations were also demonstrated between the number of laps accomplished on the 20-m SRT and upper extremity muscle strength as well as standing vertical jump height.

Muscle strength is an important anthropometric characteristic that may be used for the assessment of sprinting ability in adolescents.

We examined the relationships among and differences between muscle size and strength, specific tension (MQ ST ), echo intensity (MQ EI ), and functional performance in physically active younger and older women.

Measurements included maximal voluntary isometric knee extension contractions (MVICs), maximal velocity sit-to-stand (STS) movements, and muscle cross sectional area (mCSA), MQ ST , and MQ EI of the rectus femoris (RF).

There were no differences in MQ ST ( p = 0.96) or physical activity levels ( p = 0.29). MQ ST and MQ EI were not related in the younger women, but were related in the older women ( r = 0.50). MVIC was related to mCSA ( r = 0.75) in the older women, but was not significantly related to MQ ST or MQ EI in either age group.

Physical activity may maintain MQ ST in aging. We suggest that studies examining changes in skeletal muscle with aging utilize both traditionally calculated muscle quality (specific tension) and ultrasound EI.

Obesity and physical inactivity increase the risk for cardiovascular disease, Type 2 diabetes mellitus, hypertension, dyslipidemia and certain cancers. Exercise training and increased fitness promote positive changes in body composition and improve insulin sensitivity.

To investigate the effect of sequence order of combined strength and endurance training on new adiposity indices: visceral adiposity index (VAI), body adiposity index (BAI) and waist to hip ratio (WHtR) in overweight elderly women.

Forty overweight elderly women (age range: 60.34 ± 0.82 years old) were selected purposefully and randomly assigned into four groups: endurance, then strength (E - > S) ( n = 9 ), strength, then endurance (S = ⁣ > E) ( n = 10 ), alternative concurrent training (ACT) ( n = 12 ), and control ( n = 9 ) groups. Training was performed three times per week for eight weeks. Endurance training performed on a cycle ergometer (intensity: 60–88% MHR) and strength training included several selected exercises targeting upper and lower body (intensity: 40–75 1RM, 8–18 repeat).

The results showed that the amount of weight, BMI, body fat percentage, BAI and WHtR have significantly decreased in E + S, S + E and ACT experimental groups ( P < 0.05). No significant differences were found in VAI variable and triglyceride with sequence order of E + S and S + E, but after sequence order of ACT a significant decrease was seen in both variables ( P ⩾ 0.05). There were no statistically significant differences between the three combined training groups for the mentioned variables ( P ⩾ 0.05).

Sequence does not seem to play a role in the positive effect on current adiposity indices of the investigated training programs.

“When will I be able to play again?” is the most frequent question asked by injured athletes. Due to the complex nature of sports injury, deciding when an injured athlete may safely return to training is a critical and difficult decision.

To study if the Safe Multidimensional Algorithm for Return to Training (SMART) scores, applied before the release to full return to training after injury differs between football players who suffer a subsequent re-injury and football players who do not.

Seventy one male professional football players were prospectively monitored for injuries during two seasons. The SMART tool was applied in injured players with an absence > 10 days. The injured player had to carry out 17 multidimensional tests included in the algorithm in his final days of the planned rehabilitation. The results of the SMART were compared between players who sustained re-injuries and those who did not.

Fifty-five injuries with absence > 10 days were recorded and re-injuries occurred in 12 of these cases (22%). There was a lower re-injury rate in players who presented a better recovery in pain ( p < 0.001), agility (RR 21.0, 95% CI: 2.0 to 213.2), advanced agility (RR 26.7, 95% CI: 4.9 to 142.8), anxiety (RR 8.6, 95% CI: 2.0 to 36.2), depression (RR 10.3, 95% CI: 1.5 to 65.7), self-perception ( p < 0.001), advanced skills mode (RR 20.5, 95% CI: 3.3 to 125.9) and group skills mode ( p < 0.001).

A multidimensional approach of Return to Training that includes objective measures may indicate potential deficiencies in the recovery of injured players.

Familiarization is a fundamental step for a proper maximum strength testing. However, there is a lack of evidence regarding familiarization protocols suitable for isokinetic assessment in men with spinal cord injury (SCI).

The aim was to compare different familiarization protocols (sessions and sets) and their influences on a maximum isokinetic strength test in individuals with SCI.

Thirty-six men with SCI were enrolled and were randomly assigned to one of three groups that performed one (F1set), two (F2set) or three (F3set) sets of familiarization on an isokinetic dynamometer. Each group repeated familiarization and maximum strength tests on three different days (D1, D2 and D3) with 48 to 72-hour intervals. Multiple one-way analysis of variance was performed to compare the familiarization protocols. For measurement agreement, the intraclass correlation coefficient (ICC) with Bland-Altman plots were used.

F2set had no statistically difference in peak torque between testing days, or between F1set and F3set. F1set and F3set differed between days for shoulder abduction and extension. ICC was significant and high (ICC ⩾ 0.91; P ⩽ 0.01) comparing D1 and D3 for all.

One familiarization session composed by 2 sets of submaximal exercise could be adopted as a suitable protocol prior to a maximal strength testing in men with SCI.

Participation in outrigger canoe racing has gained rapidly in popularity across the United States, Australia, New Zealand, and Japan. Moreover, outrigger canoe racing has recently been included as an official sport of the 2016 Paralympic games in Rio de Janeiro. Hence, evaluation of upper limb pedaling strength in outrigger canoe paddlers would be important to determine optimal sport-specific training techniques for these athletes.

To compare multiple-joint isokinetic strength (MI) of upper extremity, muscle strength, and overall morphology in outrigger canoe paddlers and non-athletes.

Nine outrigger canoe paddlers (Out-C), and eight healthy male non-athletes (Con) were recruited. The MI of the upper extremity was evaluated using an isokinetic arm ergometer.

Multiple-joint isokinetic strength was greater in the Out-C group than in the Con group at all pedaling speeds ( p < 0.05). In addition, peak moment right arm extension and left arm (RL) was significantly greater than peak moment left arm extension and right arm (LR) only in the Out-C group ( p < 0.05). Significant correlations were identified between chest girth and MI at 110 rpm, left forearm girth and MI at 50 rpm, 70 rpm, and 90 rpm, right forearm girth and MI at 50 rpm ( p < 0.05).

Asymmetries in MI of upper extremity muscles with stronger left than right side may be an important contributing feature of performance.

To compare EMG activity of the hip and thigh muscles during traditional static bed exercises and the sit-to-stand exercise in healthy older adults.

Twenty-four healthy, older adults (8 males; age 65 ± 7 y) performed four static rehabilitation exercises: isometric contractions of the gluteal, abductor, inner quadriceps and quadriceps (ten, ∼ 5 s submaximal contractions, with 60 rests), and the sit-to-stand test. Electromyographic (EMG) activity was recorded from the rectus femoris, vastus medialis, gluteus medius, biceps femoris and gluteus maximus, and root mean square-processed (RMS) in this observational preliminary study. Handgrip strength and 10 m walking speed represented participant characteristics.

Hip and thigh muscles were activated differently between the isometric bed and sit-to-stand exercises. Greatest RMS activity was shown in the chair rising phase of the sit-to-stand exercise. No bed exercise exceeded the muscle RMS activity required to perform a sit-to-stand, and only for sit-to-stands were all muscles activated over 40% of maximal; the level required to stimulate muscle strength adaptation.

Functional daily activities, such as sit-to-standing, produce greater muscle activity than static bed exercises in healthy older adults. Sit-to-stands should be included in exercise and rehabilitation programs for older adults to evoke sufficient levels of neuromuscular activation for muscle strength adaptation.

Interventions using Pilates and whole body vibration (WBV) have been conducted in postmenopausal women, aimed at increasing muscular strength and quality of life; however, some results are contradictory.

To compare the effects of Pilates vs. WBV on isokinetic muscle strength and quality of life in postmenopausal women.

Fifty-one (51) women were randomly assigned to the following groups, Pilates ( n = 17), vibration ( n = 17), or control ( n = 17). Evaluations were performed for isokinetic muscular strength (N.m) of knee extensors and flexors (60 ∘ /s and 180 ∘ /s) and quality of life using the SF-36. The interventions were performed three times a week for six months, totaling 78 sessions. Analyzes for the primary outcomes were performed with intention-to-treat and covariance analyses adjusted for baseline outcomes.

96.1% of participants completed the follow-up. The Pilates was superior ( p < 0.05) to WBV for muscle strength of the knee flexors at 60 ∘ /s (% Change: 16.71 ± 20.68 vs. 6.18 ± 19.42; Cohen’s d = 0.70) and superior ( p < 0.05) to the control group in all muscular strength variables and in four SF-36 domains.

Pilates is an alternative intervention superior to WBV when the goal is linked to the strength of the knee flexor muscles.