Identification of Genomic Predictors of Muscle Fiber Size.

The greater muscle fiber cross-sectional area (CSA) is associated with greater skeletal muscle mass and strength, whereas muscle fiber atrophy is considered a major feature of sarcopenia. Muscle fiber size is a polygenic trait influenced by both environmental and genetic factors. However, the genetic variants underlying inter-individual differences in muscle fiber size remain largely unknown. The aim of our study was to determine whether 1535 genetic variants previously identified in a genome-wide association study of appendicular lean mass are associated with the CSA of fast-twitch muscle fibers (which better predict muscle strength) in the m. vastus lateralis of 148 physically active individuals (19 power-trained and 28 endurance-trained females, age 28.0 ± 1.1; 28 power-trained and 73 endurance-trained males, age 31.1 ± 0.8). Fifty-seven single-nucleotide polymorphisms (SNPs) were identified as having an association with muscle fiber size (p < 0.05). Of these 57 SNPs, 31 variants were also associated with handgrip strength in the UK Biobank cohort (n = 359,729). Furthermore, using East Asian and East European athletic (n = 731) and non-athletic (n = 515) cohorts, we identified 16 SNPs associated with athlete statuses (sprinter, wrestler, strength, and speed-strength athlete) and weightlifting performance. All SNPs had the same direction of association, i.e., the lean mass-increasing allele was positively associated with the CSA of muscle fibers, handgrip strength, weightlifting performance, and power athlete status. In conclusion, we identified 57 genetic variants associated with both appendicular lean mass and fast-twitch muscle fiber size of m. vastus lateralis that may, in part, contribute to a greater predisposition to power sports.

Influence of ACTN3 R577X Polymorphism on Blood Creatine Kinase Levels Relative to Number of Sprints in Brazilian Professional Soccer Players.

This study sought to assess how post-game creatine kinase (CK) levels correlate with the number of sprints and the impact of the ACTN3 polymorphism on this response. This research constituted a descriptive/observational, retrospective cross-sectional study. DNA was extracted from blood samples for ACTN3 polymorphism genotyping. CK was measured 48 h after official matches, and the number of sprints (>19 km/h) was tracked using Global Positioning System (GPS) technology. The main cohort included 23 professional soccer players from the top tier of the Brazilian Championship. We analyzed 115 GPS + CK data sets. The replication cohort comprised 18 professional soccer players from the First Division of the Championship, had the same methodology applied, and featured a total of 90 GPS (sprints > 25.2 km/h) + CK data sets. For the main cohort, a significant positive correlation was seen between the number of sprints and the CK levels (p = 0.009). Athletes with the ACTN3 RR genotype had higher CK levels as more sprints were performed during the match (p = 0.017). However, the relationship was not found for X allele carriers (p > 0.05). For the replication cohort, there was a near-significant correlation between CK levels and the number of sprints (p = 0.05), and RR individuals showed a significant association (p = 0.01), whereas X allele carriers did not (p = 0.06). A greater number of sprints during matches is linked to higher CK levels, primarily among players with the ACTN3 RR genotype, which is potentially due to an increased presence of type II muscle fibers. These findings were replicated for both cohorts of elite Brazilian soccer players, emphasizing the importance of genetic factors in injury prevention.

Association between parental decisions regarding abortion and severity of fetal heart disease.

The prenatal diagnosis of fetal heart disease potentially influences parental decision-making regarding pregnancy termination. Existing literature indicates that the severity, whether in complexity or lethality, significantly influences parental decisions concerning abortion. However, questions remain as to how fetal heart disease severity impacts parental decisions, given recent advancements in postsurgical outcomes. Therefore, we investigated risk factors associated with parents' decision-making regarding abortion following a prenatal diagnosis of fetal heart disease. Our analysis included 73 (terminated: n = 37; continued: n = 36) pregnancies with a fetal heart disease diagnosed before 22 weeks of gestation. Increased gestational age at diagnosis reduced the likelihood of parents' decision on termination (Model 1: adjusted odds ratio, 0.94; 95% confidence interval 0.89-0.99; Model 2: 0.95 0.90-0.997). Critical disease (5.25; 1.09-25.19) and concurrent extracardiac or genetic abnormalities (Model 1: 4.19, 1.21-14.53; Model 2: 5.47, 1.50-19.96) increased the likelihood of choosing abortion. Notably, complex disease did not significantly influence parental decisions (0.56; 0.14-2.20). These results suggest that parental decision-making regarding abortion may be influenced by earlier gestational age at diagnosis, the lethality of heart disease, and extracardiac or genetic abnormalities, but not its complexity if prenatal diagnosis and parental counseling are provided at a cardiovascular-specialized facility.

Morphological anomalies in obstructive hypertrophic cardiomyopathy: Insights from four-dimensional computed tomography and surgical correlation.

Hypertrophic cardiomyopathy (HCM) is a genetic disorder in which left ventricular outflow tract obstruction critically affects symptoms and prognosis. Traditionally, left ventricular outflow tract obstruction was primarily attributed to septal hypertrophy with systolic anterior motion of the mitral valve. However, recent evidence highlights significant contributions from the mitral valve and papillary muscle anomalies, as well as an apical-basal muscle bundle observed in HCM patients. Accurate morphological assessment is essential when considering septal reduction therapy. While transesophageal echocardiography and cardiac magnetic resonance are recommended for assessing the anomalous structures, four-dimensional computed tomography offers superior spatial resolution and multiplanar reconstruction capabilities. These features enable the evaluation of details of the morphological anomalies, such as the apical-basal muscle band, papillary muscle anomalies, subaortic stenosis, and right ventricular outflow tract obstruction. Based on the detailed assessment of these morphological features, four-dimensional computed tomography has been utilized for planning of surgical correction in a comprehensive HCM center. This approach facilitates the intervention strategies and may improve outcomes in septal reduction therapy for obstructive HCM.

Effect of sprint interval training load on maximal oxygen uptake in trained men.

BACKGROUND: Sprint interval training (SIT) improves maximal aerobic and anaerobic performance, including oxygen uptake (VO2max), power output, and sprint performance. This study aimed to investigate the effect of SIT load on V̇O2max in trained subjects. METHODS: SIT was performed twice a week for three weeks by twenty-four trained men (aged: 20.7±2.7, V̇O2max 43.6±6.5) and consisted of seven bouts of 10-s cycling sprints followed by a 4-min rest. Subjects were divided into two groups depending on the relative resistance of the load compared to their body mass (BM): 7.5% (S7.5) and 10% (S10). We measured the peak power, mean power, and peak cadence in SIT during the first and final sessions. V̇O2max, maximum aerobic power (MAP), heart rate, and lactate (La) concentration were measured before and after SIT using incremental tests. RESULTS: After 3 weeks of SIT, V̇O2max, MAP, and La improved significantly in both S7.5 and S10 groups. In addition, changes in V̇O2max in S10 were higher than those in S7.5 (2.2±11.2% vs. 9.23±9.57%, P=0.029, adjusted by pre V̇O2max). MAP measurements showed the same results (2.2±11.3% vs. 8.3±10.0%, P=0.015, adjusted by pre-MAP). However, there was no significant interaction between time and group. A significant increase in peak cadence from first session to sixth sessions was observed in S7.5 (P=0.01, ES = 0.93, 95% confidence interval [CI]: 0.02-1.78) but not in S10 (P=0.132, ES = 0.22, 95% [CI]: -0.59-1.01). CONCLUSIONS: Our results suggest that 3 weeks of SIT improves endurance performance in trained subjects. It seems that SIT at 10% load may tend to be more effective.

Association of MMP3 gene polymorphism and sex on recovery of muscle strength after eccentric exercise.

Individual differences in recovery of muscle strength after eccentric exercise may be influenced by sex and genotype. A candidate genetic polymorphism associated with response during muscle recovery is the MMP3 gene rs522616 polymorphism, encoding matrix metalloproteinase (MMP-3). Here, we investigated the effect of the MMP3 gene rs522616 polymorphism and sex on recovery of muscle strength after eccentric exercise. A total of 95 healthy subjects (50 men and 45 women) performed five sets of six maximal eccentric elbow flexion exercises. Maximal voluntary contraction (MVC) torque, range of motion (ROM), and muscle soreness, as well as blood parameters [creatine kinase (CK) and interleukin-6 (IL-6)], were assessed immediately before and after and 1, 2, 3, and 5 days after eccentric exercise. No significant time × group interaction in MVC torque after exercise was observed between groups in both sexes. Furthermore, sex differences were identified in the area under the curves (AUC) of CK and IL-6, both of which were higher in men than those in women. A significant genotype-sex interaction was identified in the recovery of MVC, calculated by subtracting the MVC immediately after exercise from the MVC on day 5 after eccentric exercise. The G allele showed a significantly lower recovery of MVC than the AA genotype in men. However, no significant differences were observed in women. This study demonstrated the interaction between the MMP3 rs522616 polymorphism and sex in recovery of muscle strength after eccentric exercise.NEW & NOTEWORTHY Sex differences were identified in the AUC of creatin kinase (CK) and interleukin 6 (IL-6) after eccentric exercise, both of which were greater in men. A genotype-sex interaction was identified in recovery of maximal voluntary contraction (MVC). The G allele showed a significantly lower recovery of MVC than AA genotype in men. To our knowledge, this is the first study to report the interaction between MMP3 gene rs522616 polymorphism and sex difference on recovery of muscle strength after eccentric exercise.

Effects of free weight and body mass-based resistance training on thigh muscle size, strength and intramuscular fat in healthy young and middle-aged individuals.

NEW FINDINGS: What is the central question of this study? How do free weight resistance training (RT) and body mass-based RT for 8 weeks compare for isometric muscular strength, muscle size and intramuscular fat (IMF) content in the quadriceps femoris? What is the main finding and its importance? Free weight and body mass-based RTs could induce muscle hypertrophy; however, decreased IMF content was observed following the body mass-based RT alone. ABSTRACT: The objective of this study was to investigate the effects of free weight and body mass-based resistance training (RT) on muscle size and thigh intramuscular fat (IMF) in young and middle-aged individuals. Healthy individuals (aged 30-64 years) were assigned to either a free weight RT group (n = 21) or a body mass-based RT group (n = 16). Both groups performed whole-body resistance exercise twice a week for 8 weeks. Free weight resistance exercises (squats, bench press, deadlift, dumbbell rows and back range) involved 70% one repetition maximum, with three sets of 8-12 repetitions per exercise. The nine body mass-based resistance exercises (leg raise, squats, rear raise, overhead shoulder mobility exercise, rowing, dips, lunge, single-leg Romanian deadlifts and push-ups) included the maximum possible repetitions per session, which were performed in one or two sets. Mid-thigh magnetic resonance images using the two-point Dixon method were taken pre- and post-training. The muscle cross-sectional area (CSA) and IMF content in the quadriceps femoris were measured from the images. Both the groups showed significantly increased muscle CSA post-training (free weight RT group, P = 0.001; body mass-based RT group, P = 0.002). IMF content in the body mass-based RT group significantly decreased (P = 0.036) but did not significantly change in the free weight RT group (P = 0.076). These results suggest that the free weight and body mass-based RTs could induce muscle hypertrophy; however, in healthy young and middle-aged individuals, decreased IMF content was induced following the body mass-based RT alone.

Body Composition, Anthropometric Parameters, and Strength-Endurance Characteristics of Sport Climbers: A Systematic Review.

ABSTRACT: Ginszt, M, Saito, M, Zieba, E, Majcher, P, and Kikuchi, N. Body composition, anthropometric parameters, and strength-endurance characteristics of sport climbers: a systematic review. J Strength Cond Res 37(6): 1339-1348, 2023-Sport climbing was selected to be part of the Summer Olympic Games in Tokyo 2021 with 3 subdisciplines: lead climbing, speed climbing, and bouldering. The nature of physical effort while speed climbing, lead climbing, and bouldering performance is different. This literature review aimed to describe differences between body composition, anthropometric parameters, and upper-limb strength-endurance variables between sport climbers with different ability levels and nonclimbers. The following databases were searched: PubMed and Scopus. The following keywords were used: "sport climbing," "rock climbing," "lead climbing," and "bouldering." Articles were considered from January 2000 to October 2021 if they concerned at least one of the following parameters: body composition (mass, body mass index, body fat, lean muscle mass, bone mineral density), anthropometric parameters (height, ape index), muscle strength (MVC finger strength in half-crimp grip, MVC finger strength to body mass, handgrip strength), and muscle endurance (force time integral, pull-ups). A review shows that body mass and body fat content were lower in the sport climbers compared with controls and in elite sport climbers compared with those less advanced. Sport climbers presented higher values of MVC finger strength in half-crimp grip, MVC finger strength to body mass, handgrip strength, and force time integral parameter than control subjects. Significantly higher MVC values in half-crimp grip were observed in elite sport climbers than in advanced athletes. None of the analyzed work showed differences between sport climber groups in the ape index. The abovementioned parameters may be a key factor in elite sport climbing performance.

Increase in children with developmental delay: Survey on 18-month-old children in Togane city, Japan.

BACKGROUND: Individuals who visit hospitals with neurodevelopmental disorders have recently increased. To locate the cause for this increase, various factors, such as environmental and genetic ones, are being investigated. The objective of this study is to analyze the developmental delay in children and their background. METHODS: The participants were children who underwent the checkup for 18-month-old children in Togane city, Japan, from 2011 to 2021; 4,145 children-2,147 boys and 1,998 girls with a mean age of 18.8 months-were included. To examine the tendency over time and the background, we used the questionnaire about development and lifestyle reported by parents. RESULTS: The number of children who did not produce pointing gestures or respond to their names and low-volume sounds tended to increase over the survey period (p = 0.0125, p = 0.0435, p = 0.0275). Next, we examined the relationship between pointing gestures and lifestyle and found that there was a relationship between attending a nursery school and bedtime and pointing gestures. CONCLUSION: A slow developmental trend over the last decade has been observed among children. The background was related to attending a nursery school and bedtime, suggesting that interaction with others and sleep are important for the development of children.

The Association between ACTN3 R577X Polymorphism and Range of Motion: A Systematic Review and Meta-analysis.

The R577X polymorphism in the α-actinin-3 gene (ACTN3) is associated with muscle strength and power; there is an association between ACTN3 R577X polymorphism and range of motion (ROM). We examined the effect of the ACTN3 R577X polymorphism on ROM through meta-analysis and systematic review. Relevant studies published before April 14, 2022 were identified from the PubMed database using the following keywords and Boolean operators: ("flexibility" or "Joint Range of Motion" or "Joint Flexibility" or "Range of motion") and ("ACTN3" or "alpha-actinin 3"). Studies that met the following criteria were included: (1) published in English, (2) included human subjects, (3) provided ROM measurements, and (4) analyzed the ACTN3 R577X genotype. A total of 2908 participants from seven studies were included in the meta-analysis. The additive genetic model was assessed using a meta-regression model, and dominant and recessive models were analyzed using a random effects model. The ROM in the XX+RX genotype was significantly higher than that in the RR genotype (recessive model: p<0.001), and it increased additively in the order XX>RX>RR (additive model: p=0.029). However, no significant association was observed in the dominant model. These findings further elucidate the association between flexibility and the ACTN3 R577X genotype.

Effect of Online Home-Based Resistance Exercise Training on Physical Fitness, Depression, Stress, and Well-Being in Middle-Aged Persons: A Pilot Study.

PURPOSE: This study investigated the effect of online home-based resistance exercise training on fitness, depression, stress, and well-being. A total of 67 individuals participated. Of them, 28 participants (13 men and 15 women, average age: 45.1 ± 12.2 years) performed the same exercise training online (n = 17), using Zoom, or in person (n = 11) in 2020 (Study 1). In addition, 39 participants (15 men and 24 women; average age: 47.6 ± 10.8 years) performed eight weeks of online home-based resistance exercise training in 2021 (Study 2). The participants performed low-load resistance exercises twice a week for eight weeks (16 sessions). Muscle strength, thigh muscle cross-sectional area, fitness parameters, blood pressure, mental health (Center for Epidemiologic Studies-Depression Scale-CES-D; and Kessler Psychological Distress scale-K6), and well-being (Well-Being Index-WHO-5) were measured pre-and post-resistance training. In Study 1, eight weeks of online home-based resistance training improved CES-D (p = 0.003), and a similar tendency was observed in resistance training (RT) with the in-person group (p = 0.06). There was a significant improvement in CES-D symptoms after the online home-based resistance training in Study 2 (p = 0.009). However, there were no significant changes in the WHO-5 and K6. Our results suggest that online low-load resistance training improves fitness parameters and curbs depressive status.

Does resistance exercise lifting velocity change with different rest intervals?

BACKGROUND: In this study, we examined the sex difference of the effect of rest intervals on lifting velocity during resistance exercise. METHODS: Twenty-two trained subjects (11 men and 11 women) were included. Each protocol consisted of 3 sets of 10 repetitions at 70% of 1- repetition maximum (1RM) with rest intervals of 90 s (R90), 150 s (R150), and 240 s (R240) in a crossover design. The exercise did parallel squats with free weights. The measurement items are lifting velocity (mean velocity) in each repetition and blood lactate concentration after exercise. RESULTS: There was a significant interaction between changes in the average velocity of 10 repetition in each set (AV10rep) and sex in each protocol, indicating that AV10rep during squat exercise has decreased in men but not in women in each protocol (P=0.002-0.03). CONCLUSIONS: Our results suggested that short rest intervals will not recover lifting velocity between short rest intervals until the next set at men, while women will be able to recover even with short rest intervals.

The Association between Total Genotype Score and Athletic Performance in Weightlifters.

This study aimed to investigate the relationship between power-oriented genetic polymorphisms and weightlifting status, create a total genotype score (TGS), and validate the association between TGS models and power-oriented athletes. First, 192 weightlifters and 416 controls were studied, and 12 polymorphisms that have previously been associated with strength, power status, and phenotype were genotyped using the TaqMan SNP genotyping assay. We calculated the TGS for the 12 polymorphisms using a PWM (power-oriented whole model) and for 6 of them using a WRM (weightlifting-related model) based on a case-control study. Second, the TGS of the WRM was compared for 177 strength and power athletes and 416 controls. There was no significant difference in the PWM score between weightlifters and the controls. Weightlifters and elite weightlifters had higher WRM scores than the controls. However, the WRM score had no association with weightlifting performance. There was no significant difference in the WRM between power-oriented athletes and the controls. Our study was able to create a TGS model for weightlifters based on case-control results. However, the TGS model could not be applied to other power-oriented athletes.

ALDH2 gene polymorphism is associated with fitness in the elderly Japanese population.

PURPOSE: The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism, which is exclusive to the Asian population, is related to many diseases. A high reactive oxygen species production in mitochondria, and low muscle strength in athletes and non-athletes, has been observed, as our previous study demonstrated. The purpose of this research was to investigate the influence of ALDH2 rs671 on the loss of muscle strength with aging and replicate our previous study in non-athletes. METHODS: Healthy Japanese individuals (n = 1804) aged 23-94 years were genotyped using DNA extracted from saliva. Muscle strength was assessed using grip strength and chair stand test (CST). The interaction between age and genotypes was analyzed by two-way analysis of covariance (ANCOVA) adjusted for sex, body mass index (BMI), and exercise habit. RESULTS: Individuals aged ≧55 with the AA genotype had a lower performance than those with the GG + GA genotype in the grip strength test (28.1 ± 9.1 kg vs. 29.1 ± 8.3 kg, p = 0.021). There was an interaction between age and genotype, where individuals with ≧55 years old AA genotype had a higher loss of strength compared to GG + GA genotypes in the CST (0.025). No interaction in other models and no sex differences were found. CONCLUSION: This study replicated previous results of the relationship between the AA genotype with lower muscle strength and as a novelty showed that this genotype is associated with a higher age-related loss of strength.

Genetic profile of sports climbing athletes from three different ethnicities.

This study aimed to investigate the ACTN3 R577X, ACE I/D, CKM rs8111989, and TRHR rs7832552 genotypes in climbers and controls in three ethnicities. The study consisted of 258 climbers (Japanese, n = 100; Polish, n = 128; Russian, n = 30) and 1151 controls (Japanese: n = 332, Polish: n = 635, Russian: n = 184). Genotyping results were analyzed using the TaqMan approach in Japanese and Polish subjects and HumanOmni1-Quad Bead Chips in Russian subjects. There were no significant differences in ACTN3 R577X and ACE I/D polymorphism distribution between climbers and controls in any ethnic cohort or model. The frequencies of the C allele in the CKM polymorphism and the T allele in the TRHR polymorphism were higher in climbers than in controls only in the Russian cohort (p = 0.045 and p = 0.039, respectively). The results of the meta-analysis on three cohorts showed that the frequency of XX + RX genotypes in the ACTN3 R577X polymorphism was significantly higher in climbers than that in the controls (p = 0.01). The X allele of the ACTN3 R577X polymorphism was associated with sport climbing status, as assessed using a meta-analysis of climbers across three different ethnicities.

The Association between the ALDH2 rs671 Polymorphism and Athletic Performance in Japanese Power and Strength Athletes.

The rs671 polymorphism is associated with the enzymatic activity of aldehyde dehydrogenase 2 (ALDH2), which is weakened by the A allele in East Asians. We recently reported the association of this polymorphism with the athletic status in athletic cohorts and the muscle strength of non-athletic cohorts. Therefore, we hypothesized the association of ALDH2 rs671 polymorphism with the performance in power/strength athletes. We aimed to clarify the relationship between the ALDH2 rs671 polymorphism and performance in power/strength athletes. Participants comprising 253 power/strength athletes (167 men and 86 women) and 721 healthy controls (303 men and 418 women) were investigated. The power/strength athletes were divided into classic powerlifting (n = 84) and weightlifting (n = 169). No differences in the genotypes and allele frequencies of the ALDH2 rs671 polymorphism and an association between performance and the ALDH2 rs671 genotype were observed in weightlifters. However, the relative values per body weight of the total record were lower in powerlifters with the GA + AA genotype than those with the GG genotype (7.1 ± 1.2 vs. 7.8 ± 1.0; p = 0.010, partial η2 = 0.08). Our results collectively indicate a role of the ALDH2 rs671 polymorphism in strength performance in powerlifters.

Glycated hemoglobin level on admission associated with progression to severe disease in hospitalized patients with non-severe coronavirus disease 2019.

AIMS/INTRODUCTION: Poor glycemic control is known to be associated with severe infection development. This retrospective observational study examined whether glycemic control before coronavirus disease 2019 (COVID-19) onset contributes to progression from non-severe to severe COVID-19. MATERIALS AND METHODS: Glycated hemoglobin (HbA1c) was measured on hospital admission in 415 patients with non-severe COVID-19. The outcome was determined from time of hospital admission to severe progression, based on clinical practice guidelines for COVID-19 in Japan. RESULTS: The median value for HbA1c on admission was 6.1%, with diabetes present in 138 patients (33.3%). Among the total cohort, 93 (22.4%) progressed to severe COVID-19 with a median (interquartile range) time of 4 days (3-7 days), whereas 322 (77.6%) were discharged after 13 days (10-17 days). A multivariable Cox proportional hazards regression model showed that HbA1c level on admission was independently associated with progression to severe COVID-19 (hazard ratio for 1% increase 1.237, 95% confidence interval 1.037-1.475; P = 0.018), with findings consistent among several sensitivity analyses. In subgroup analyses, such an association was significant in patients with diabetes, as well as older age, current smoking habit, lower estimated glomerular filtration rate, higher C-reactive protein level, moderate II COVID-19, dyslipidemia and chronic respiratory disease, with no remarkable inconsistency among the subgroups. Finally, higher HbA1c level (≥7%) was more strongly associated with severe COVID-19 progression than diabetes. CONCLUSIONS: The results suggest that poor glycemic control before COVID-19 onset contributes to progression from non-severe to severe COVID-19, even in patients with severe COVID-19 risk factors regardless of the presence of diabetes.

Is COL1A1 Gene rs1107946 Polymorphism Associated with Sport Climbing Status and Flexibility?

The purpose of this study was to compare the frequency of COL1A1 rs1107946 polymorphism between sport climbers and controls from three ethnic groups (Japanese, Polish, and Russian) and investigate the effect of the COL1A1 rs1107946 polymorphism on the age-related decrease in flexibility in the general population. Study I consisted of 1929 healthy people (controls) and 218 climbers, including Japanese, Polish, and Russian participants. The results of the meta-analysis showed that the frequency of the AC genotype was higher in climbers than in the controls (p = 0.03). Study II involved 1093 healthy Japanese individuals (435 men and 658 women). Flexibility was assessed using a sit-and-reach test. There was a tendency towards association between sit-and-reach and the COL1A1 rs1107946 polymorphism (genotype: p = 0.034; dominant: p = 0.435; recessive: p = 0.035; over-dominant: p = 0.026). In addition, there was a higher negative correlation between sit-and-reach and age in the AA + CC genotype than in the AC genotype (AA + CC: r = −0.216, p < 0.001; AC: r = −0.089, p = 0.04; interaction p = 0.037). However, none of these results survived correction for multiple testing. Further studies are warranted to investigate the association between the COL1A1 gene variation and exercise-related phenotypes.

The Effect of Online Low-intensity Exercise Training on Fitness and Cardiovascular Parameters.

Online exercise is undoubtedly useful and important; however, chronic adaptations to online exercise, particularly strength gain, muscle hypertrophy, and cardiovascular parameters, remain unclear. We investigated the effect of online exercise training using Zoom on fitness parameters compared with the same exercises supervised directly. In the present study, 34 subjects (age: 42.9±14.4 years) were included. Twenty-three subjects performed 8 weeks of body mass-based exercise training online using Zoom, and eleven subjects performed the same exercise supervised directly as the control group. The subjects performed low-load resistance exercises twice a week for 8 weeks for a total of 16 sessions. The sessions included 9 exercises: leg raises, squats, rear raises, shoulder presses, rowing, dips, lunges, Romanian dead lifts, and push-ups. Chair-stand, push-up, and sit-and-reach tests were performed on all subjects. Overall, the home exercise program effectively increased strength and muscle mass and decreased blood pressure and arterial stiffness, but there were no differences between the groups. Changes in chair-stand and sit-and-reach test results were higher in the control group than in the online group. Our results show that there is a similar training response to body mass-based training in both groups, even with virtual experiences using Zoom.