Effects of Resistance Training on Oxidative Stress Markers and Muscle Damage in Spinal Cord Injured Rats

Background: Spinal cord injury (SCI) is a condition that affects the central nervous system, is characterized by motor and sensory impairments, and impacts individuals’ lives. The objective of this study was to evaluate the effects of resistance training on oxidative stress and muscle damage in spinal cord injured rats. Methodology: Forty Wistar rats were selected and divided equally into five groups: Healthy Control (CON), Sham (SHAM) SCI Untrained group (SCI-U), SCI Trained group (SCI- T), SCI Active Trained group (SCI- AT). Animals in the trained groups were submitted to an incomplete SCI at T9. Thereafter, they performed a protocol of resistance training for four weeks. Results: Significant differences in muscle damage markers and oxidative stress in the trained groups, mainly in SCI- AT, were found. On the other hand, SCI- U group presented higher levels of oxidative stress and biomarkers of LDH and AST. Conclusion: The results highlight that resistance training promoted a decrease in oxidative stress and a significative response in muscle damage markers.

Brief inductive learning but not explicit instruction of a new grammar can produce a Whorfian effect

It is known that brief training on new vocabulary and metaphors can shift how we represent concepts and categorize stimuli even when we are not using the language. But it remains unknown whether brief training on grammar can also produce such ‘Whorfian’ effects. Besides, previous studies have neglected how the way in which the language was learned might be a factor. To fill these gaps, Mandarin native speakers learned a new grammatical marker of transitivity through either inductive training or explicit instruction. In subsequent non-verbal matching task the inductively trained group based their judgments on the number of entities involved in motion events to a greater extent than controls naïve to the grammar, but the explicitly trained group did not, despite showing equivalent knowledge of the grammar in a grammaticality judgment task. We interpret the effects in terms of dynamic and unconscious top-down feedback from grammar to lower-level perceptual processes.

Isometric, Eccentric, and Concentric Strength in Trained and Untrained Older Adults: A Pilot Study

Background: Despite an overall decrease in muscular strength, older adults maintain eccentric (ECC) strength in greater proportions compared to isometric (ISO) and concentric (CON) strength. While resistance training is promoted for older adults, the impact of resistance training on ISO, ECC, and CON strength is relatively unknown. Objective: The purpose of this study was to compare peak ISO, ECC and CON knee extensor moments between trained and untrained older individuals. Methods: A quasi-experimental design with a two-group comparison, ex post facto, was conducted. Twenty older adults (8 females, 69.6 ± 6.1 years, 80.5 ± 16.4 kg, 1.7 ± 0.1 m) were allocated to two groups, one undergoing resistance training (n =10) and one not (n = 10). An isokinetic dynamometer measured ISO, ECC, and CON knee extensor moments. Peak knee extensor moments (Nm) and ECC: ISO ratio were analyzed using a Kruskal-Wallis test (α = 0.05). Spearman Rank-Order Correlations were run on paired combinations of peak ISO, ECC, and CON moments for both groups. Results: The trained group had significantly greater peak ISO moment (183.8 vs 137.1 Nm, p = 0.013, d = 1.3) but significantly lower ECC: ISO ratio (p = 0.028, d = 1.1). The trained group exhibited stronger correlations for ECC-ISO (rs = 0.79 vs. 0.65), ECC-CON (rs = 0.93 vs. 0.59), and CON-ISO (rs = 0.93 vs. 0.78) compared to the untrained group. Conclusions: The findings demonstrate older adults maintain eccentric and concentric strength, regardless of training status. However, trained participants had a more balanced ECC: ISO ratio, due to their increased peak ISO strength possibly due to their resistance training.

Effects of Greater Central Arterial Stiffness on Cardiovagal Baroreflex Sensitivity in Resistance-Trained Men

Background Compared with age-matched untrained men, resistance-trained men who have undergone long duration training (> 2 years) at a high frequency (> 5 days/week) may be lower cardiovagal baroreflex sensitivity (BRS) because of central arterial stiffening. Therefore, the purpose of this study was to examine the effect of greater central arterial stiffness in resistance-trained men on cardiovagal BRS in a cross-sectional study to compare resistance-trained men with age-matched untrained men. Methods This cross-sectional study included resistance-trained men (n = 20; age: 22 ± 3; body mass index: 26.7 ± 2.2) and age-matched untrained men (control group: n = 20; age: 25 ± 2; body mass index: 23.7 ± 2.4). The β-stiffness index and arterial compliance were assessed at the right carotid artery using a combination of a brightness mode ultrasonography system for the carotid artery diameter and applanation tonometry for the carotid blood pressure. And, the cardiovagal BRS was estimated by the slope of the R–R interval and systolic blood pressure during Phase II and IV of Valsalva maneuver (VM). The participants maintained an expiratory mouth pressure of 40 mmHg for 15 s in the supine position. Results The β-Stiffness index was significantly higher in the resistance-trained group than in the control group (5.9 ± 1.4 vs. 4.4 ± 1.0 a.u., P < 0.01). In contrast, the resistance-trained group had significantly lower arterial compliance (0.15 ± 0.05 vs. 0.20 ± 0.04 mm2/mmHg, P < 0.01) and cardiovagal BRS during Phase IV of VM (9.0 ± 2.5 vs. 12.9 ± 5.4 ms/mmHg, P < 0.01) than the control group and. Moreover, cardiovagal BRS during Phase IV of VM was inversely and positively correlated with the β-stiffness index (r = − 0.59, P < 0.01) and arterial compliance (r = 0.64, P < 0.01), respectively. Conclusion Resistance-trained group had greater central arterial stiffness and lower cardiovagal BRS Phase IV compared with control group. Moreover, the central arterial stiffening was related to cardiovagal BRS Phase IV. These results suggest that greater central arterial stiffness in resistance-trained men may be associated with lower cardiovagal BRS. Trial Registration University hospital Medical Information Network (UMIN) in Japan, UMIN000038116. Registered on September 27, 2019.

Characteristics of Japanese Electrolaryngeal Speech Produced by Untrained Speakers: An Observational Study Involving Healthy Volunteers

Purpose The aim of this study was to investigate the characteristics of electrolaryngeal (EL) speech among untrained speakers to aid in its effective introduction and to identify syllables and words that are easy or difficult to pronounce. Method A total of 21 healthy individuals who had never used an EL were included. The participants were briefed, and tests comprising 100 Japanese syllables and 50 single words were conducted to evaluate EL speech intelligibility. A trained speaker was defined as a certified speech-language pathologist who underwent EL training for 3 months. A 5-point electrolarynx effectivity score (EES) was used for the subjective assessment of EL. Results The median (interquartile range) intelligibility scores of the untrained and trained groups were 24.0% (20.0%–34.0%) and 40.0% (36.0%–45.0%) for syllables and 48.0% (38.0%–60.0%) and 88.0% (82.0%–90.0%) for words, respectively. The intelligibility scores for syllables and words were higher in the trained group than those in the untrained group. Only two syllable subgroups (/m/ and /w/) had > 80% correct answers among untrained speakers. A total of 14 syllable subgroups (/k, kʲ, s, ɕ, t, t͡ɕ, ts, ɲ, h, ç, ɸ, p, pʲ, and a/), a number of which contained voiceless consonants, had < 40% correct answers among both speaker groups. A greater number of morae were associated with higher intelligibility scores. An EES of 4, indicating that the EL was effective, was the most frequent score. Conclusions It was difficult for untrained speakers to produce intelligible speech using an EL. Syllables, including voiceless consonants, were difficult to pronounce using an EL. Longer words with a greater number of morae were more intelligible, even for untrained EL speakers. Supplemental Material https://doi.org/10.23641/asha.16632622

Energy Expenditure during Acute Weight Training Exercises in Healthy Participants: A Preliminary Study

Energy expenditure during weight training exercises produces great fitness and health benefits for humans, but few studies have investigated energy expenditure directly during weight training. Therefore, in this study, we aimed to determine energy costs during three training sessions consisting of three different exercises. Ten participants were randomly allocated into two groups: an untrained (n = 5, with no weight training experience) and a trained group (n = 5, with some weight training experience). Each participant completed three training sessions on separate days. While wearing a mask for indirect calorimetric measurements, each participant participated in training sessions conducted with three dumbbell exercises: the bent-over row, deadlift, and lunge. Metabolic equivalents (METs), energy expenditure (EE), respiratory exchange ratio (RER), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and rate of perceived exertion (RPE) were measured. The total energy cost was calculated from the oxygen consumption (VO2) during each exercise. Our results showed that the METs of a single training session were 3.3 for the untrained group and 3.4 for the trained group, while the sum of the EE was 683–688 and 779–840 kcal, respectively. The physiological parameters, such as heart rate (p = 0.001 *) for the lunge and rate of perceived exertion (p = 0.005 *) for the bent-over row, changed significantly in both groups. It was concluded that the exercise protocol of this study involved a moderate intensity of 2.4–3.9 METs. The energy cost of each training exercise was between 179 and 291 kcal.

Hepatic ischemia reperfusion injury: effect of moderate intensity exercise and oxytocin compared to l-arginine in a rat model

Background Hepatic ischemia reperfusion (IR) injury is considered as a main cause of liver damage and dysfunction. The l-arginine/nitric oxide pathway seems to be relevant during this process of IR. Although acute intense exercise challenges the liver with increased reactive oxygen species (ROS), regular training improves hepatic antioxidant status. Also, oxytocin (Oxy), besides its classical functions, it exhibits a potent antistress, anti-inflammatory, and antioxidant effects. This study was designed to evaluate the hepatic functional and structural changes induced by hepatic IR injury in rats and to probe the effect and potential mechanism of moderate intensity exercise training and/or Oxy, in comparison to a nitric oxide donor, l-arginine, against liver IR-induced damage. Results Compared to the sham-operated control group, the hepatic IR group displayed a significant increase in serum levels of ALT and AST, plasma levels of MDA and TNF-α, and significant decrease in plasma TAC and nitrite levels together with the worsening of liver histological picture. L-Arg, Oxy, moderate intensity exercise, and the combination of both Oxy and moderate intensity exercises ameliorated these deleterious effects that were evident by the significant decrease in serum levels of ALT and AST, significant elevation in TAC and nitrite, and significant decline in lipid peroxidation (MDA) and TNF-α, besides regression of histopathological score regarding hepatocyte necrosis, vacuolization, and nuclear pyknosis. Both the moderate intensity exercise-trained group and Oxy-treated group showed a significant decline in TNF-α and nitrite levels as compared to l-Arg-treated group. The Oxy-treated group showed statistical insignificant changes in serum levels of ALT, AST, and plasma levels of nitrite, MDA, TAC, and TNF-α as compared to moderate intensity exercise-trained group. Conclusion The combination of both moderate intensity exercise and Oxy displayed more pronounced hepatoprotection on comparison with l-Arg which could be attributed to their more prominent antioxidant and anti-inflammatory effects but not due to their NO-enhancing effect.

Applicability of Maximal Ergometer Testing and Sprint Performance in Adolescent Endurance and Sprint Trained Swimmers

Sprint swimming is a short duration, high intensity sport requiring a relatively greater contribution of energy from anaerobic metabolism. Understanding energy system utilization for the classification of a competitive swimmer (sprint or distance) may be useful for both training prescription and event specialization. The relationship between anaerobic swim ergometer testing and adolescent sprint swimming performance has not been investigated. The purpose of this study was to compare the performance and physiological responses during a maximal all-out ergometer test as well as the maximal anaerobic lactate test in a group of sprint vs. middle-distance specialized swimmers. Sixteen (n = 16) competitive swimmers (mean ± standard deviation (SD), age 16.8 ± 0.7 year; body mass 67.3 ± 9.8 kg) were categorized into two gender matched groups: sprint (n = 8) and middle-distance (n = 8). Each athlete performed (1) a 45 s swim ergometer maximal test to determine peak and mean power output (Watts (W)), (2) a MANLT test to determine peak and average velocity as well as the post-exercise lactate response, and (3) a 50 m swim time trial. The sprint group showed a higher mean (p = 0.026) and peak (p = 0.031) velocity during the MANLT. In addition, blood lactate concentration was significantly (p < 0.01) higher in the sprint vs. middle-distance trained group at 3 and 12 min after completion of the MANLT (3-min post 11.29 ± 2.32 vs. 9.55 ± 3.48 mmol/L; 12-min post 8.23 ± 2.28 vs. 7.05 ± 2.47 mmol/L). The power output during the 45 s all-out swimming ergometer test was higher in the sprint trained group. The results of this study demonstrate the anaerobic contribution to sprint swimming measured during an all-out dryland ergometer test.

Effects of Vigorous Resistance Training On Cardiovagal Baroreflex Sensitivity: A Cross-Sectional Study

Background: Blunted cardiovagal baroreflex sensitivity (BRS) is correlated with elevation of central arterial stiffness and/or reduction of arterial compliance with aging. Resistance-trained who habitually perform vigorous resistance training (RT) may blunt cardiovagal BRS due to an increase in central arterial stiffness and a decrease in arterial compliance. Therefore, the purpose of this study was to examine the effect of vigorous RT on cardiovagal BRS in a cross-sectional study to compare resistance-trained with age-matched non-resistance-trained.Methods: This cross-sectional study included resistance-trained men (resistance-trained group: n = 20) and age-matched non-resistance-trained men (control group: n = 20). The β-stiffness index and arterial compliance were assessed at the right carotid artery, and the cardiovagal BRS was estimated by the slope of the R-R interval and systolic blood pressure during phase IV of the Valsalva maneuver.Results: The β-Stiffness index was significantly higher in the resistance-trained group than in the control group (4.4 ± 0.2 vs. 5.9 ± 0.3 a.u., P < 0.01). In contrast, the resistance-trained group had significantly lower arterial compliance and cardiovagal BRS than the control group (0.20 ± 0.01 vs. 0.15 ± 0.01 mm2/mmHg and 12.9 ± 1.2 vs. 9.0 ± 0.5 ms/mmHg, respectively, P < 0.01 for both measurements). Moreover, cardiovagal BRS was inversely and positively correlated with the β-stiffness index (combined: r = - 0.59, P < 0.01; control: r = - 0.56, P < 0.01; resistance-trained: r = - 0.50, P < 0.05) and arterial compliance (combined: r = 0.64; control: r = 0.61; resistance-trained: r = 0.55, all P < 0.01), respectively. Conclusion: Resistance-trained group was higher arterial stiffness and lower compliance and blunter cardiovagal BRS compared with control group. These results suggest that vigorous RT blunts cardiovagal BRS.Trial registration: University hospital Medical Information Network (UMIN) in Japan, UMIN000038116. Registered on September 27, 2019.

Resistance Training Diminishes the Expression of Exosome CD63 Protein without Modification of Plasma miR-146a-5p and cfDNA in the Elderly

Aging-associated inflammation is characterized by senescent cell-mediated secretion of high levels of inflammatory mediators, such as microRNA (miR)-146a. Moreover, a rise of circulating cell-free DNA (cfDNA) is also related to systemic inflammation and frailty in the elderly. Exosome-mediated cell-to-cell communication is fundamental in cellular senescence and aging. The plasma changes in exercise-promoted miR-146a-5p, cfDNA, and exosome release could be the key to facilitate intercellular communication and systemic adaptations to exercise in aging. Thirty-eight elderly subjects (28 trained and 10 controls) volunteered in an 8-week resistance training protocol. The levels of plasma miR-146a-5p, cfDNA, and exosome markers (CD9, CD14, CD63, CD81, Flotillin [Flot]-1, and VDAC1) were measured prior to and following training. Results showed no changes in plasma miR-146a-5p and cfDNA levels with training. The levels of exosome markers (Flot-1, CD9, and CD81) as well as exosome-carried proteins (CD14 and VDAC1) remained unchanged, whereas an attenuated CD63 response was found in the trained group compared to the controls. These findings might partially support the anti-inflammatory effect of resistance training in the elderly as evidenced by the diminishment of exosome CD63 protein expression, without modification of plasma miR-146a-5p and cfDNA.