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1.
Effect of Leg Eccentric Exercise on Muscle Damage of the Elbow Flexors after Maximal Eccentric Exercise.
Chen, TC, Chen, HL, Cheng, LF, Chou, TY, Nosaka, K
Medicine and science in sports and exercise. 2021;(7):1473-1481
Abstract
PURPOSE The magnitude of muscle damage induced by maximal eccentric exercise is attenuated when the same exercise is repeated by homologous muscle of the ipsilateral or contralateral limb. It is not known if the muscle damage-protective effect is also transferred to nonhomologous muscles. The present study investigated the effects of unilateral knee extensor (KE) or flexor (KF) eccentric exercise on muscle damage induced by elbow flexor (EF) eccentric exercise of the ipsilateral or contralateral side. METHODS Young healthy sedentary men were assigned to four experimental groups (n = 13 per group) that performed five sets of six maximal eccentric contractions (MaxEC) of the KE or KF of the same or opposite side of the arm that performed MaxEC of the EF 1 wk later, and a control group that performed two bouts of MaxEC of the EF using a different arm for each bout separated by 1 wk. Changes in several indirect muscle damage markers were compared among the groups by mixed-design, two-way ANOVA. RESULTS Changes in maximal voluntary concentric contraction torque, range of motion, muscle soreness, and plasma creatine kinase activity after KE or KF MaxEC were not different (P > 0.05) between legs, but greater (P < 0.05) after KF than KE MaxEC. The changes in the variables after EF MaxEC in the experimental groups were not different (P > 0.05) from the first bout of the control group but larger (P < 0.05) than the second bout of the control group, and no differences between the ipsilateral and contralateral sides were evident. CONCLUSIONS These results showed that no protective effect on EF MaxEC was conferred by the leg exercises, suggesting that muscle damage protection was not transferred from KE or KF to EF.
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2.
Striking muscle adaptations induced by volume-dependent repeated bouts of low-intensity eccentric exercise of the elbow flexors.
Chen, TC, Tseng, WC, Chen, HL, Tseng, KW, Chou, TY, Huang, YC, Nosaka, K
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2021;(8):897-905
Abstract
We investigated the effects of repeating 30 low-intensity eccentric contractions with a dumbbell corresponding to 10% maximal isometric strength (10%EC) on muscle strength and hypertrophy, and muscle damage after 30 maximal eccentric contractions (MaxEC) of the elbow flexors. Young men were placed into 1 of 3 experimental groups that performed 10%EC either once, twice a week for 4 (8 bouts) or 8 weeks (16 bouts) before MaxEC, or a control group that performed 2 bouts of MaxEC separated by 2 weeks (n = 13/group). Repeating 16 bouts of 10%EC increased (P < 0.05) maximal voluntary contraction strength (30 ± 21%) and muscle thickness (4.2 ± 2.3%) greater than 8 bouts (16 ± 4%, 1.9 ± 1.3%). Changes in the muscle damage markers after MaxEC were smaller (P < 0.05) for the experimental groups than the control group, and the magnitude of muscle damage protection was greater (P < 0.05) after 16 bouts (65 ± 30%) than 8 bouts (55 ± 33%), followed by 1 bout (34 ± 27%). The protection by 16 bouts was similar (P = 0.81) to that shown by the second MaxEC of the control group. These results showed that 10%EC produced potent muscle adaptation effects accumulatively and conferred muscle damage protection, but 1 bout of 10%EC was still effective for conferring approximately 20% of the protection of that by 16 bouts. Novelty: Repeating low-intensity eccentric exercise induces large increases in muscle strength and hypertrophy. Low-intensity eccentric exercise protects muscle damage induced by maximal eccentric contractions, and the protection is reinforced by repeating it. These are especially beneficial for individuals who are frail and cannot tolerate high-intensity resistance training.
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3.
Muscle damage protective effect by two maximal isometric contractions on maximal eccentric exercise of the elbow flexors of the contralateral arm.
Chen, TC, Lin, MJ, Chen, HL, Lai, JH, Yu, HI, Nosaka, K
Scandinavian journal of medicine & science in sports. 2018;(4):1354-1360
Abstract
Muscle damage after 30 maximal eccentric contractions of the elbow flexors (30MVEC) is reduced when the same exercise is performed by the opposite arm, and when two maximal voluntary isometric contractions at a long muscle length (2MVIC) are performed prior to 30MVEC by the same arm. This study investigated the hypothesis that 2MVIC would attenuate muscle damage after 30MVEC performed by the opposite arm. Untrained young (20-25 years) men were placed into 1 of 4 experimental groups that performed 2MVIC at 1 (1d), 2 (2d), 4 (4d), or 7 days (7d) before 30MVEC by the opposite arm, or one control group that performed 30MVEC only (n = 13/group). Changes in indirect muscle damage markers after 30MVEC were compared among the groups by mixed-design two-way ANOVA. Maximal voluntary concentric contraction torque, range of motion, plasma creatine kinase activity, and muscle soreness did not change significantly after 2MVIC. Changes in these variables after 30MVEC were smaller (P < .05) for 1d (eg, peak soreness: 45 ± 21 mm) and 2d groups (46 ± 20 mm) than control group (66 ± 18 mm), without significant differences between 1d and 2d groups. No significant differences in the changes were found among 4d, 7d, and control groups, except for soreness showing smaller (P < .05) increases for 4d group (54 ± 19 mm) than 7d (62 ± 17 mm) and control groups. These results supported the hypothesis and showed that muscle damage induced by 30MVEC was reduced by 2MVIC performed 1-2 days prior to 30MVIC by the contralateral arm.
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4.
Acute effects of caffeine on strength and muscle activation of the elbow flexors.
Trevino, MA, Coburn, JW, Brown, LE, Judelson, DA, Malek, MH
Journal of strength and conditioning research. 2015;(2):513-20
Abstract
The purpose of this study was to examine the effects of caffeine on strength and muscle activation of the elbow flexors. Thirteen recreationally active male volunteers (mean ± SD, age: 21.38 ± 1.26 years) came to the laboratory 4 times. Visit 1 served as a familiarization visit. During visits 2 through 4, subjects ingested a randomly assigned drink, with or without caffeine (0, 5, or 10 mg·kg of body mass), and performed 3 maximal isometric muscle actions of the elbow flexors 60 minutes after ingestion. Maximal strength and rate of torque development (RTD) were recorded. Electromyographic (EMG) and mechanomyographic (MMG) amplitude and frequency, and electromechanical delay (EMD), and phonomechanical delay (PMD) were measured from the biceps brachii. The results indicated that the ingestion of 0 (placebo), 5, or 10 mg·kg of body mass of caffeine did not significantly influence (p > 0.05) peak torque, RTD, normalized EMG amplitude or frequency, normalized MMG amplitude, or EMD and PMD. Normalized MMG frequency was significantly lower (p ≤ 0.05) following ingestion of 5 mg·kg of body mass of caffeine compared with the placebo trial. This was most likely an isolated finding because MMG frequency was the only variable to have a significant difference across all trials. The results suggested that ingestion of either 5 or 10 mg·kg of body mass of caffeine does not provide an ergogenic effect for the elbow flexors during isometric muscle actions.
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5.
Whey protein does not enhance the adaptations to elbow flexor resistance training.
Erskine, RM, Fletcher, G, Hanson, B, Folland, JP
Medicine and science in sports and exercise. 2012;(9):1791-800
Abstract
PURPOSE It is unclear whether protein supplementation augments the gains in muscle strength and size observed after resistance training (RT) because limitations to previous studies include small cohorts, imprecise measures of muscle size and strength, and no control of prior exercise or habitual protein intake. We aimed to determine whether whey protein supplementation affected RT-induced changes in elbow flexor muscle strength and size. METHODS We pair-matched 33 previously untrained, healthy young men for their habitual protein intake and strength response to 3-wk RT without nutritional supplementation (followed by 6 wk of no training) and then randomly assigned them to protein (PRO, n = 17) or placebo (PLA, n = 16) groups. Participants subsequently performed elbow flexor RT 3 d · wk(-1) for 12 wk and consumed PRO or PLA immediately before and after each training session. We assessed elbow flexor muscle strength (unilateral 1-repetition maximum and isometric maximum voluntary force) and size (total volume and maximum anatomical cross-sectional area determined with magnetic resonance imaging) before and after the 12-wk RT. RESULTS PRO and PLA demonstrated similar increases in muscle volume (PRO 17.0% ± 7.1% vs PLA 14.9% ± 4.6%, P = 0.32), anatomical cross-sectional area (PRO 16.2% ± 7.1% vs PLA 15.6% ± 4.4%, P = 0.80), 1-repetition maximum (PRO 41.8% ± 21.2% vs PLA 41.4% ± 19.9%, P = 0.97), and maximum voluntary force (PRO 12.0% ± 9.9% vs PLA 14.5% ± 8.3%, P = 0.43). CONCLUSIONS In the context of this study, protein supplementation did not augment elbow flexor muscle strength and size changes that occurred after 12 wk of RT.
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6.
[Distraction arthrodiatasis in elbow stiffness].
Pennig, D, Mader, K, Heck, S
Operative Orthopadie und Traumatologie. 2009;(6):521-32
Abstract
OBJECTIVE Loss of motion of the elbow is not uncommon after trauma, burns, or coma and severely impairs upper limb function. Loss of motion may be difficult to avoid and is challenging to treat. Detailed analysis of the etiology and diagnostic evaluation are of utmost importance for planning any surgical intervention for elbow stiffness. Most activities of daily living are possible, if the elbow has a range of motion of 100 degrees (30-130 degrees of flexion, Morrey's arc of motion). INDICATIONS Stiff elbow, usually defined as less than 30 degrees extension or less than 130 degrees flexion. CONTRAINDICATIONS Poor compliance, poorly controlled diabetes mellitus, active hepatitis B and C infection, HIV infection, acute articular infection. SURGICAL TECHNIQUE Current operative techniques, such as closed distraction with external fixation (arthrodiatasis), are presented and evaluated. Elbow arthrolysis is a technically demanding procedure. POSTOPERATIVE MANAGEMENT If indication and techniques are used correctly and surgeon, physiotherapist, and patient are familiar with the procedure, good long-term results may be achieved. RESULTS In 14 children and adolescents the results after 5 years showed an increase of preoperative range of motion from 37 degrees to 108 degrees (flexion/extension; 75-130 degrees ) postoperatively.
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7.
Electromyographic instantaneous amplitude and instantaneous mean power frequency patterns across a range of motion during a concentric isokinetic muscle action of the biceps brachii.
Beck, TW, Housh, TJ, Johnson, GO, Cramer, JT, Weir, JP, Coburn, JW, Malek, MH
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2006;(5):531-9
Abstract
The purpose of this study was to examine the electromyographic (EMG) instantaneous amplitude (IA) and instantaneous mean power frequency (IMPF) patterns for the biceps brachii muscle across a range of motion during maximal and submaximal concentric isokinetic muscle actions of the forearm flexors. Ten adults (mean +/- SD age = 22.0 +/- 3.4 years) performed a maximal and a submaximal [20% peak torque (PT)] concentric isokinetic forearm flexion muscle action at a velocity of 30 degrees s(-1). The surface EMG signal was detected from the biceps brachii muscle with a bipolar electrode arrangement, and the EMG IA and IMPF versus time relationships were examined for each subject using first- and second-order polynomial regression models. The results indicated that there were no consistent patterns between subjects for EMG IA or IMPF with increases in torque across the range of motion. Some of the potential nonphysiological factors that could influence the amplitude and/or frequency contents of the surface EMG signal during a dynamic muscle action include movement of the muscle fibers and innervation zone beneath the skin surface, as well as changes in muscle fiber length and the thickness of the tissue layer between the muscle and the recording electrodes. These factors may affect the EMG IA and IMPF patterns differently for each subject, thereby increasing the difficulty of drawing any general conclusions regarding the motor control strategies that increase torque across a range of motion.
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8.
Responses of elbow flexors to two strenuous eccentric exercise bouts separated by three days.
Chen, TC, Nosaka, K
Journal of strength and conditioning research. 2006;(1):108-16
Abstract
This study investigated whether the second eccentric exercise performed 3 days after the initial bout would exacerbate muscle damage and retard the recovery. Fifty-one athletes performed 30 eccentric actions of the elbow flexors using a dumbbell weighted 100% of the maximal isometric force (MIF) at the elbow joint angle of 90 degrees (ECC1). Three days after ECC1, all subjects except those in the control group (n = 12) performed the second bout (ECC2) with the same (100%) intensity (n = 12), 90% (n = 13), or 80% (n = 14) of the ECC1. Some subjects, especially in the 100% group, required spotting for ECC2 but made maximal effort to complete the exercise. MIF, range of motion, upper-arm circumference, muscle soreness, muscle proteins in the blood, and ultrasound images were used to assess muscle damage. Changes in these measures for 9 days following ECC1 were compared among groups by 2-way analysis of variance (ANOVA) with repeated measures. All criterion measures changed significantly after ECC1; however, no significant differences between the groups were evident for any of the changes in the measures. These results suggest that it is possible for athletes to complete the second bout if the intensity is reduced 10-20% from the initial bout. No significant differences between the control group and other groups indicate that the second eccentric exercise performed 3 days after the initial bout does not exacerbate muscle damage and retard the recovery regardless of the intensity of the second bout. It is concluded that the elbow flexors can perform high-intensity eccentric exercise in the early stage of recovery from the initial bout and are not damaged further by performing a subsequent bout 3 days after the first.
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9.
[Surgical treatment of type I capitellar-humeral fractures using the Henry ventral approach approach. Short- and medium-term results].
Dietz, SO, Müller, LP, Korner, J, Rommens, PM
Der Unfallchirurg. 2005;(3):200-2, 204-5
Abstract
Capitellar fractures are rare. Despite adequate surgical treatment, patients suffer frequently from limited range of motion, osteonecrosis, and neurological deficits. The purpose of this retrospective study was to evaluate short- and medium-term surgical results in seven patients who had type I capitellar fractures according to Bryan and Morrey. All patients were treated via an anterior approach, according to Henry, and open reduction and internal fixation with two screws. Seven patients were examined clinically, neurologically, and radiologically after 10-65 months. The fracture healed in all patients. None of the patients had a neurological deficit. According to the Morrey Score, five of seven patients had an excellent or good functional result. Open reduction and internal fixation with two screws via the Henry approach is a suitable option for surgical treatment for type I capitellar fractures.