Damage and the repeated bout effect of arm, leg, and trunk muscles induced by eccentric resistance exercises

Nosaka

Medicine &Amp; Science in Sports &Amp; Exercise

et al. 2019

Self Cite

Purpose: Unilateral resistance training increases muscle strength of the contralateral homologous muscle by the cross-education effect. Muscle damage induced by second eccentric exercise bout is attenuated, even when it is performed by the contralateral limb. The present study compared the effects of unilateral eccentric training (ET) and concentric training (CT) of the elbow flexors (EF) on maximal voluntary isometric contraction (MVC) strength and muscle damage of the contralateral untrained EF. Methods: Young men were placed into ET, CT, ipsilateral repeated bout (IL-RB), and contralateral repeated bout (CL-RB) groups (n = 12 per group). The ET and CT groups performed unilateral EF training consisting of five sets of six eccentric and concentric contractions, respectively, once a week for 5 wk by increasing the intensity from 10% to 100% of MVC, followed by 30 maximal eccentric contractions (30MaxEC) of the opposite EF 1 wk later. The IL-RB group performed two bouts of 30MaxEC separated by 2 wk using the nondominant arm, and CL-RB group performed two bouts of 30MaxEC with a different arm for each bout in 1-wk apart. Results: The MVC increased (P < 0.05) greater for the trained (19% ± 8%) and untrained (11% ± 5%) arms in ET when compared with those in CT (10% ± 6%, 5% ± 2%). The magnitude of changes in muscle damage markers was reduced by 71% ± 19% after the second than the first bout for IL-RB group, and by 48% ± 21% for CL-RB group. Eccentric training and CT attenuated the magnitude by 58% ± 25% and 13% ± 13%, respectively, and the protective effect of ET was greater (P < 0.05) than CL-RB, but smaller (P < 0.05) than IL-RB. Conclusions: These results showed that cross-education effect was stronger for ET than CT, and progressive ET produced greater contralateral muscle damage protective effect than a single eccentric exercise bout.

Section: Progressive Trainingmentioning

confidence: 99%

Contralateral Effects by Unilateral Eccentric versus Concentric Resistance Training

Nosaka

Medicine &Amp; Science in Sports &Amp; Exercise

et al. 2019

Self Cite

“…However, it remains controversial whether the intensity of the exercise was consistent with the markedly elevated levels of serum CK (Honda et al, 2017 ). Chen et al ( 2019 ) found with resistance training, that CK levels are higher when training is on consecutive days. Thus, subjecting CrossFit ® training practitioners to a higher volume and intensity of training for successive days may expose the practitioner to the risk of damage associated with muscle cell necrosis.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Hormonal, Metabolic, and Inflammatory Responses in CrossFit® Training: A Systematic Review

Jacob¹,

Novaes

Behm

et al. 2020

Front. Physiol.

Background: CrossFit® training is a high-intensity functional training program that aims to increase physical functional performance through biochemical responses, i.e., hormonal, metabolic, and inflammatory responses. Most hormonal, metabolic, and inflammatory changes induced by CrossFit® training have been reported in isolated clinical studies. The purpose of this review was to systematically explore the existing literature on characterization of hormonal, metabolic, and inflammatory responses resulting from CrossFit® training. Methods: A systematic search of the literature was conducted in PubMed, Web of Science and Scopus from August 2019 to October 2019. Studies were selected through critical review of the content. Using specific keywords, 623 articles were found, of which 597 were excluded for ineligibility, and 25 were eligible. The papers were separated according to subject area: hormonal ( n = 8), metabolic ( n = 19), and inflammatory ( n = 6) changes. All were published between 2015 and 2019. Results: This review reveals potential effects of CrossFit® training on hormonal, metabolic, and inflammatory responses. However, studies had low levels of evidence and reliability due to methodological limitations. Conclusion: In summary, the results showed a greater volume and intensity of workouts accentuate the responses, that are of paramount importance for improving understanding of the effects of CrossFit ® training and serve as a basis for prescribing future exercise protocols.

“…angle, ROM, MVIC, SOR, muscle circumference, plasma CK and myoglobin levels, and ultrasound echo intensity between elbow flexors and knee extensors after an extension contraction exercise reported that the knee extensors showed significantly lower values for all the measured items compared to the flexor muscles. Chen et al 20) , who compared sensitivity to EIMD among nine muscles (elbow flexors, elbow extensors, pectoralis, knee extensors, knee flexors, plantar flexors, latissimus, abdominis, and erector spinae), reported that the elbow flexor was the muscle most susceptible to pain, whereas the plantar flexor muscle came sixth in the list. Another previous study 21) reported that the degree of EIMD was influenced by the frequency of exposure to eccentric contraction on a daily basis; thus, the EIMD of lower limb muscles, which are used on a daily basis for eccentric loads such as running, jumping, and walking down stairs, show significantly less EIMD compared to the upper limbs.…”

Section: Discussionmentioning

confidence: 99%

N-terminal fragments of titin in urine as a biomarker for eccentric exercise-induced muscle damage

Yamaguchi

Suzuki

Kanda

et al. 2020

JPFSM

N-terminal fragments of titin in urine have been proposed as a noninvasive marker of muscle damage, but there are no data on its time course after 96 h. The aims of this study were to investigate the time course of urinary titin N-terminal fragment (UTF) following eccentric exercise and the subsequent correlations between UTF and other muscle damage indices. Seventeen healthy young men performed 30 maximal isokinetic eccentric exercises at the elbow flexors. Muscle soreness (SOR), range of motion (ROM), maximal voluntary isometric contraction (MVIC), creatine kinase (CK), and UTF were sampled before, immediately after, and 24-144 h after exercise. The changes and correlations were analyzed with one-way ANO-VA and Spearman's rank correlation analysis. All the measured parameters showed significant differences from their pre-exercise values at 24 h or later after exercise (P < 0.05). UTF showed significant correlation with MVIC (r ≤-0.485) at 24 h and later, with SOR (r ≥ 0.549) at 48 h and later, with ROM (r ≤-0.485) at 48 h and later, and with CK (r ≥ 0.647) at all time points. UTF reached peak value at 96 h after the exercise and had not recovered completely at 144 h. Because UTF was highly correlated with the other muscle damage indices, especially CK, throughout the measurement period, it may be as useful an indicator of muscle damage as CK obtained from blood.