The influence of resistance exercise training prescription variables on skeletal muscle mass,strength,and physical function in healthy adults:An umbrella review

Purpose:The aim of this umbrella review was to determine the impact of resistance training(RT)and individual RT prescription variables on muscle mass,strength,and physical function in healthy adults.Methods:Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines,we systematically searched and screened eligible systematic reviews reporting the effects of differing RT prescription variables on muscle mass(or its proxies),strength,and/or physical function in healthy adults aged>18 years.Results:We identified 44 systematic reviews that met our inclusion criteria.The methodological quality of these reviews was assessed using A Measurement Tool to Assess Systematic Reviews;standardized effectiveness statements were generated.We found that RT was consistently a potent stimulus for increasing skeletal muscle mass(4/4 reviews provide some or sufficient evidence),strength(4/6 reviews provided some or sufficient evidence),and physical function(1/1 review provided some evidence).RT load(6/8 reviews provided some or sufficient evidence),weekly frequency(2/4 reviews provided some or sufficient evidence),volume(3/7 reviews provided some or sufficient evidence),and exercise order(1/1 review provided some evidence)impacted RT-induced increases in muscular strength.We discovered that 2/3 reviews provided some or sufficient evidence that RT volume and contraction velocity influenced skeletal muscle mass,while 4/7 reviews provided insufficient evidence in favor of RT load impacting skeletal muscle mass.There was insufficient evidence to conclude that time of day,periodization,inter-set rest,set configuration,set end point,contraction velocity/time under tension,or exercise order(only pertaining to hypertrophy)influenced skeletal muscle adaptations.A paucity of data limited insights into the impact of RT prescription variables on physical function.Conclusion:Overall,RT increased muscle mass,strength,and physical function compared to no exercise.RT intensity(load)and weekly frequency impacted RT-induced increases in muscular strength but not muscle hypertrophy.RT volume(number of sets)influenced muscular strength and hypertrophy.

Investigating the Physiological Mechanisms between Resistance Training and Pain Relief in the Cancer Population: A Literature Review

This literature review examines the mechanisms of how exercise, specifically in the form of resistance training, may lead to pain relief in the cancer population. Primary data from three different cancer populations: breast, prostate, and lung, will be examined. A number of experimental studies have been conducted to confirm the effectiveness of resistance training on pain relief as well as the biochemical pathways that relate to this process. In this review, we will examine 5 randomized controlled trials. For the purposes of this review, pain is defined as physical suffering or discomfort associated with illness. Pain is the body’s natural signal, bringing attention to damage that has been sustained by tissues. However, chronic pain is common in the cancer population, and often serves no good purpose but instead will negatively impact both physical and mental health. The three types of pain: nociceptive, neuropathic, and inflammatory pathways have been investigated, and the knowledge of pain mechanisms allows for the understanding of how it is associated with pain. The purpose of this exploratory literature review is to give insight on how to maximize pain-relieving effects of resistance training. Research has indicated that resistance training modulates pain pathways by upregulating the release of pain-relieving substances including beta-endorphins, anti-inflammatory cytokines, and endocannabinoids. Understanding of the benefits of resistance training may be useful in relieving cancer pain, and reproducing effects of pain-relieving strategies while minimizing the symptoms related to cancer and its treatment.

Effect of Resistance Training,Aerobic Exercise Before Doula-Assisted Delivery on the Psychological Well-Being and Labor Duration of Parturients

Objective:To investigate the impact of resistance training and aerobic exercise before doula-assisted delivery on the psychological well-being and labor duration of parturients.Methods:105 cases of parturients who gave birth in our hospital from February 2021 to April 2023 were included in this study.The patients were divided into a control group of 52 cases and an observation group of 53 cases.The patients in the control group received no particular intervention before delivery and only received doula assistance.The patients in the observation group received resistance training,aerobic exercise,and doula assistance prior to giving birth.After delivery,the mothers were observed for 2 hours in the delivery room and then returned to the maternal and infant ward.The observation indicators of the two groups were compared.Results:In comparison to the control group,the observation group exhibited shorter durations in the first,second,and third stages of labor,as well as the total delivery time.Additionally,the amount of postpartum blood loss at 2 hours was smaller in the observation group.The rate of cesarean section was lower,and the rate of vaginal natural delivery was higher in the observation group.Following the intervention,both groups of postpartum women showed decreased SAS and SDS scores compared to before the intervention.Moreover,the observation group had lower scores than the control group.These differences were all statistically significant(P<0.05).Conclusion:Resistance training and aerobic exercise before doula-assisted delivery can effectively improve the psychological state of parturients,shorten labor duration,increase the rate of natural vaginal delivery,and reduce pain and postpartum hemorrhage.

Effectiveness of progressive resistance training in improving muscle strength in myasthenia gravis:a single subject study design

Background:To investigate the effectiveness of the progressive resistance training(PRT)using thera band in improving muscle strength in myasthenia gravis(MG).Methods:In this prospective study,12 MG patients with generalised stable disease performed progressive resistance training with thera band for four times per week for 24 weeks.The isometric muscle force of shoulder abductors,biceps brachii and knee extensors using handheld dynamometer,Myasthenia Gravis Composite(MGC)score,Quantitative myasthenia gravis score(QMG),were assessed before and after the training period.Results:Progressive resistance training was well tolerated,and the isometric muscle strength was significantly improved in shoulder abductors,biceps brachii and knee extensors(P<0.05).The disease course(QMG and MGC)was slowed down and improved(P<0.05).Conclusion:Progressive resistance training is effective in improving muscle strength specifically in most affected muscles in MG.

Muscle strength deficits are associated with low bone mineral density in young pediatric cancer survivors:The iBoneFIT project

Background Pediatric cancer survivors are at increased risk of muscle weakness and low areal bone mineral density(aBMD).However,the prevalence of muscle strength deficits is not well documented,and the associations of muscle strength with aBMD are unknown in this population.Therefore,this study aimed to investigate the prevalence of upper-and lower-body muscle strength deficits and to examine the associations of upper-and lower-body muscle strength with age-,sex,and race-specific aBMD Z-scores at the total body,total hip,femoral neck,and lumbar spine.Methods This cross-sectional study included 116 pediatric cancer survivors(12.1±3.3 years old,mean±SD;42.2%female).Upper-and lower-body muscle strength were assessed by handgrip and standing long jump test,respectively.Dual‑energy X‑ray absorptiometry was used to measure aBMD(g/cm2).Associations between muscle strength and aBMD were evaluated in multivariable linear regression models.Logistic regression was used to evaluate the contribution of muscle strength(1-decile lower)to the odds of having low aBMD(Z-score≤1.0).All analyses were adjusted for time from treatment completion,radiotherapy exposure,and body mass index.Results More than one-half of survivors were within the 2 lowest deciles for upper-(56.9%)and lower-body muscle strength(60.0%)in comparison to age-and sex-specific reference values.Muscle strength deficits were associated with lower aBMD Z-scores at all sites(B=0.133–0.258,p=0.001–0.032).Each 1-decile lower in upper-body muscle strength was associated with 30%–95%higher odds of having low aBMD Z-scores at all sites.Each 1-decile lower in lower-body muscle strength was associated with 35%–70%higher odds of having low aBMD Z-scores at total body,total hip,and femoral neck.Conclusion Muscle strength deficits are prevalent in young pediatric cancer survivors,and such deficits are associated with lower aBMD Z-scores at all sites.These results suggest that interventions designed to improve muscle strength in this vulnerable population may have the added benefit of improving aBMD.

Suppressive effects of exercise-conditioned serum on cancer cells:A narrative review of the influence of exercise mode,volume,and intensity

Cancer is a major cause of morbidity and mortality worldwide,and the incidence is increasing,highlighting the need for effective strategies to treat this disease.Exercise has emerged as fundamental therapeutic medicine in the management of cancer,associated with a lower risk of recur-rence and increased survival.Several avenues of research demonstrate reduction in growth,proliferation,and increased apoptosis of cancer cells,including breast,prostate,colorectal,and lung cancer,when cultured by serum collected after exercise in vitro(i.e.,the cultivation of cancer cell lines in an experimental setting,which simplifies the biological system and provides mechanistic insight into cell responses).The underlying mechanisms of exercise-induced cancer suppressive effects may be attributed to the alteration in circulating factors,such as skeletal muscle-induced cytokines(i.e.,myokines)and hormones.However,exercise-induced tumor suppressive effects and detailed information about training interventions are not well investigated,constraining more precise application of exercise medicine within clinical oncology.To date,it remains unclear what role different training modes(i.e.,resistance and aerobic training)as well as volume and intensity have on exercise-condi-tioned serum and its effects on cancer cells.Nevertheless,the available evidence is that a single bout of aerobic training at moderate to vigorous intensity has cancer suppressive effects,while for chronic training interventions,exercise volume appears to be an influential candidate driving cancer inhibitory effects regardless of training mode.Insights for future research investigating training modes,volume and intensity are provided to further our understanding of the effects of exercise-conditioned serum on cancer cells.

Timing theory continuous nursing,resistance training:Rehabilitation and mental health of caregivers and stroke patients with traumatic fractures

BACKGROUND Stroke is the leading cause of adult lifelong disability worldwide.A stroke is an acute cerebrovascular disease with a variety of causes and corresponding clinical symptoms.Around 75%of surviving stroke patients experience impaired nerve function,and some suffer from traumatic fractures,which can lead to special care needs.AIM To determine the effect of timing theory continuous care,with resistance training,on the rehabilitation and mental health of caregivers and stroke patients with traumatic fractures.METHODS Between January 2017 to March 2021,we selected 100 hospital admissions with post-stroke hemiplegia complicated with a traumatic fracture.Two participant groups were created:(1)Control group:given resistance training;and(2)Observation group:given timing theory continuous care combined with resistance training.The degree of satisfaction and differences in bone and phosphorus metabolism indexes between the two groups were compared.The self-perceived burden scale(SPBS)and caregiver burden questionnaire were used to evaluate the psychological health of patients and caregivers.The Harris hip function score,ability of daily living(ADL)scale,and global quality of life questionnaire(GQOL-74)were used to evaluate hip function,ability of daily living,and quality of life.RESULTS Data were collected prior to and after intervention.Alkaline phosphatase(ALP),osteocalcin,and vitamin D3 in the observation group and control group increased after intervention(P<0.05),and carboxy-terminal peptide of type I collagenβSpecial sequence(β-CTX)decreased(P<0.05).ALP and osteocalcin in the observation group were higher than in the control group(P<0.05).There was no significant difference inβ-CTX and vitamin D3 between the two groups(P>0.05).The SPBS score of the observation group was lower and the ADL score was higher than the control group.The burden score was lower and the Harris hip function and GQOL-74 scores were higher than that of the control group(P<0.05).The observation group’s satisfaction rating was 94.00%,which was higher than the rating from the control group(P<0.05).CONCLUSION Timing theory continuous nursing with resistance training can reduce hip dysfunction in stroke patients with a traumatic fracture and enhance quality of life and mental health of patients and caregivers.

Effectiveness and time-course adaptation of resistance training vs. plyometric training in prepubertal soccer players

Purpose:This study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training(RT)vs.plyometric training(PT)in prepubertal soccer players.Methods:Thirty-four male subjects were assigned to:a control group(n=11);an RT group(5 regular soccer training sessions per week,n=12);a PT group(3 soccer training sessions and 2 RT sessions per week,n=11).The outcome measures included tests for the assessment of muscle strength(e.g.,1 repetition maximum half-squat test),jump ability(e.g.,countermovement jump,squat jump,standing long jump,and multiple 5 bounds test),linear speed(e.g.,20m sprint test),and change of direction(e.g.,Illinois change of direction test).Results:The RTG showed an improvement in the half-squat(△=13.2%;d=1.3,p<0.001)and countermovement jump(△=9.4%;d=2.4,p<0.001)at Week 4,whereas improvements in the 20-m sprint(△=4.2%;d=1.1,p<0.01);change of direction(CoD)(△=3.8%;d=2.1,p<0.01);multiple 5 bounds(△=5.1%;d=1.5,p<0.05);standing long jump(△=7.2%;d=1.2,p<0.01);squat jump(△=19.6%;d=1.5,p<0.01);were evident at Week 8.The PTG showed improvements in CoD(△=2.1%;d=1.3,p<0.05);standing long jump(△=9.3%;d=1.1,p<0.01);countermovement jump(△=16.1%;d=1.2,p<0.01);and squat jump(△=16.7%;d=1.4,p<0.01);at Week 8 whereas improvements in the 20-m sprint(△=4.1%;d=1.3,p<0.01);and multiple 5 bounds(△=7.4%;d=2.4,p<0.001);were evident only after Week.The RT and PT groups showed improvements in all sprint,CoD,and jump tests(p<0.05)and in half-squat performance,for which improvement was only shown within the RTG(p<0.001).Conclusion:RT and PT conducted in combination with regular soccer training are safe and feasible interventions for prepubertal soccer players.In addition,these interventions were shown to be effective training tools to improve explosive actions with different time courses of improvements,which manifested earlier in the RTG than in the PTG.These outcomes may help coaches and fitness trainers set out clear and concise goals of training according to the specific time course of improvement difference between RT and PT on proxies of athletic performance of prepubertal soccer players.

Blood flow restriction in human skeletal muscle during rest periods after high-load resistance training down-regulates miR-206 and induces Pax7

Backgroud:Blood flow re striction(BFR) with low-intensity re sistance training has been shown to result in hypertrophy of skeletal muscle.In this study,we tested the hypothesis that BFR during the rest periods between acute,high-intensity resistance exercise sessions(70% of 1 repetition maximum,7 sets with 10 repetitions) enhances the effects of the resistance training.Methods:A total of 7 healthy young men performed squats,and between sets BFR was carried out on one leg while the other leg served as a control.Because BFR was applied during rest periods,even severe occlusion pressure(approximately 230 mmHg),which almost completely blocked blood flow,was well-tolerated by the participants.Five muscle-specific microRNAs were measured from the biopsy samples,which were taken 2 h after the acute training.Results:Doppler data showed that the pattern of blood flow recovery changed significantly between the first and last BFR.microRNA-206 levels significantly decreased in the BFR leg compared to the control.The mRNA levels of RAC-β serine/threonine-protein kinase v22,nuclear re spiratory factor 1,vascular endothelial growth factor,lupus Ku autoantigen protein p70 genes(p <0.05),and paired box 7(p <0.01) increased in the BFR leg.The protein levels of paired box 7,nuclear respiratory factor 1,and peroxisome proliferator-activated receptor y coactivator 1α did not differ between the BFR leg and the control leg.Conclusion:BFR,during the rest periods of high-load resistance training,could lead to mRNA elevation of those proteins that regulate angiogenesis,mitochondrial biogenesis,and muscle hypertrophy and repair.However,BFR also can cause DNA damage,judging from the increase in mRNA levels of lupus Ku autoantigen protein p70.

Resistance Training in People at Risk of Developing Type 2 Diabetes and Their Experience of Health-Related Quality of Life

Background: Research indicates an association between impaired glucose metabolism and overweight, a serious public health problem involving an increased risk of Type 2 diabetes, related hypertension, and a reduced quality of life. Aim: The first aim is to assess different dimensions of Health-Related Quality of Life (HRQoL) in overweight individuals at risk of developing Type 2 diabetes compared to a normal population. The second aim is to examine the impact of resistance training on the pre-post HRQoL dimension scores of the intervention group. Methods: Eighteen participants were randomly assigned to one of the two resistance training groups. Group 1 engaged in supervised maximal resistance training (Bernstein inverted pyramid system: 5× 3 - 4, 60% - 85% of 1 Repetition Maximum (RM)), three days/week over four months, and Group 2 performed endurance resistance training (including lower weight loads and more repetitions over four months). The intervention consisted of eight exercises involving the entire body. The subjects completed the Short-Form Health Survey (SF-36) on HRQoL. The HRQoL scores of the norm population were higher than those of people at risk of developing Type 2 diabetes, and resistance training seemed to have a limited significant positive effect on the different HRQoL dimensions.

Analysis and Study on the Effect of PNF Stretching and Resistance Training on the Rehabilitation of Superior Chiasma Syndrome

In this paper,18 subjects with superior chiasma syndrome were analyzed and studied according to the inducement and correction method of superior chiasma syndrome by questionnaire survey,literature review and experimental research.To explore the effect of bad posture on the posture of patients,and to explore the effect of PNF stretching,anti-resistance training and manual loosening on the rehabilitation of patients with superior chiasma.Methods:the subjects were divided into three experimental groups,A,B and C,for 6 weeks,4 times a week for resistance training and PNF stretching training.It has been proved that the population with chest ambushes for a long time will cause the imbalance of muscle strength of shoulder,neck and chest,abnormal physiological curvature of cervical vertebrae and thoracic vertebrae,and induce chronic injury of shoulder and neck muscles and soft tissue,which will lead to symptoms of superior chiasma syndrome.According to the designed rehabilitation training experiment,PNF stretching training and anti-resistance training were carried out for the shoulder and neck muscles which caused superior chiasma syndrome,and the rehabilitation effect was very significant,which was obviously better than that of PNF stretching or resistance training alone.Therefore,PNF stretching and resistance training should be fully combined in rehabilitation training to improve the posture problem in order to achieve twice the result with half the effort.

Association between IGF-2 gene and fat-free mass in response to resistance training

BACKGROUND: It is well established that the human aging process is associated with a significant decline in neuromuscular function and performance. Twin studies demonstrate that genetic factors partially explain the inter-individual variation of fat-free mass (FFM) and muscle strength. PURPOSE: To examine the association between the polymorphism of the gene IGF-2 with phenotypes strength and muscle mass of elderly women pre and post resistance training. METHODS: 76 elderly women participated in this analysis. These volunteers, who should be sedentary for at least 6 months before the study, were assigned four groups in relation to allele GAGG, AA, GAAA and GG. The first analysis compared 60 elderly women with GG and GA allele (GAGG) versus 16 elderly women with AA allele. The second analysis compared 54 elderly women with GA and AA (GAAA) versus 22 elderly women GG allele. The Body mass index, fat free mass, fat mass and Isokinetic Muscle Peak Torque were measured. All volunteers were participating in the Resistance Training program. The DNA was extracted from peripheral venous blood leukocytes using a salting out protocol. The primer for IGF-II gene exon 9 was 5’-GTCCCTGAACCAGCAAAGAG-3’ 0.5 μM (0.625 μl) Primer R-5’-TGATGGAAAAGGGAGTGAGG-3’ 0.5 μM (0.625 μl), Taq DNA Polimerase enzime 0.5 U (0.1 μl), água milli-Q (3.8 μl) 5 hg de DNA (3 μl). PCR amplification was performed in a programmable thermal cycler GeneAmp? PCR System 9700. RESULTS: The results of the first analysis GAGG × AA versus the group AA showed the relative increase in knee extensor peak torque relative and also in the fat-free mass and showed a decrease in the fat mass percentage in the GAGG group. The second analysis considered the group GAAA versus group GG showed decreases in the fat-free mass percentage in the GAAA group, also showed the relative increase in the fat-free mass in the GG group and decrease in the fat mass percentage in the GG group. CONCLUSIONS: The results of this study show that 24 weeks of the resistance training improved strength and muscle mass and decreased the fat mass. The results confirm this assertion and suggest the G allele presents more influence over the A allele, in relation to phenotypes strength and muscle mass in elderly women after resistance training.

Application of cross-migration theory in limb rehabilitation of stroke patients with hemiplegia

BACKGROUND Stroke is a common cause of neurological dysfunction,often resulting in hemiplegia.Thus,rehabilitation of limb function in stroke patients is an important step towards accelerating recovery and improving quality of life.AIM To investigate whether unilateral strength training in hemiplegic stroke patients could lead to cross-migration,an increase in bilateral muscle strength,and an improvement in lower limb motor function.METHODS We randomly divided 120 patients with hemiplegic stroke into two groups:Eexperimental and control groups,with 60 patients in each group.Both groups received routine rehabilitation treatment,while the experimental group additional-ly received ankle dorsiflexion resistance training on the healthy side for 6 wk.We measured the maximum voluntary contract(MVC),changes in surface electromyography(EMG),and the lower limb motor function using the simplified Fugl Meyer Motor Function Assessment Scale(FMA)before and within 1 wk after training.RESULTS The FMA score in the experimental group improved significantly compared to both their pre-training score and the control group's post-training score(P<0.05).The integrated EMG of the anterior tibialis muscle and pulmonary intestine muscle in the experimental group were significantly different after training than before(P<0.05).Furthermore,the MVC of the anterior tibialis muscle on both the healthy and affected sides and the MVC of the pulmonary intestine muscle on both sides showed significant improvement compared with before training and the control group(P<0.05).CONCLUSION Our findings suggest that ankle dorsiflexion resistance training on the healthy side in hemiplegic stroke patients can increase strength in the opposite tibialis anterior muscle and antagonist's muscle,indicating a cross-migration phenomenon of strength training.Furthermore,this type of training can also improve lower limb motor function,providing a new exercise method for improving early ankle dorsiflexion dysfunction.

Associations between aerobic and muscle-strengthening physical activity,sleep duration,and risk of all-cause mortality:A prospective cohort study of 282,473 U.S.adults

Purpose:To examine the joint associations between meeting guidelines for physical activity(PA)and sleep duration and all-cause mortality risk among adults.Methods:Participants were adults(n=282,473)aged 18-84 years who participated in the 2004-2014 U.S.National Health Interview Survey.Mortality status was ascertained using the National Death Index through December 2015.Self-reported PA(Active:meeting both aerobic(AER)and muscle-strengthening(MSA)guidelines,AER only(AER),MSA only(MSA),or not meeting either AER or MSA(Inactive))and sleep duration(Short,recommended(Rec),or Long)were classified according to guidelines,and 12 PA-sleep categories were derived.Adjusted hazard ratios and 95%confidence intervals(95%CIs)for all-cause mortality risk were estimated using Cox proportional hazards regression models.Results:A total of 282,473 participants(55%females)were included;18,793 deaths(6.7%)occurred over an average follow-up of 5.4 years.Relative to the Active-Rec group,all other PA-sleep groups were associated with increased mortality risk except for the Active-Short group(hazard ratio=1.08;95%CI:0.92-1.26).The combination of long sleep with either MSA or Inactive appeared to be synergistic.For a given sleep duration,mortality risk progressively increased among participants classified as AER,MSA,and Inactive.Within each activity level,the mortality risk was greatest among adults with long sleep.Conclusion:Relative to adults meeting guidelines for both PA and sleep duration,adults who failed to meet guidelines for both AER and muscle strengthening PA and who also failed to meet sleep duration guidelines had elevated all-cause mortality risks.These results support interventions targeting both PA and sleep duration to reduce mortality risk.

Exercise interventions for patients with type 1 diabetes mellitus:A narrative review with practical recommendations

Type 1 diabetes mellitus(T1DM)is a chronic endocrine disease that results from autoimmune destruction of pancreatic insulin-producingβcells,which can lead to microvascular(e.g.,retinopathy,neuropathy,and nephropathy)and macrovascular complications(e.g.,coronary arterial disease,peripheral artery disease,stroke,and heart failure)as a consequence of chronic hyperglycemia.Despite the widely available and compelling evidence that regular exercise is an efficient strategy to prevent cardiovascular disease and to improve functional capacity and psychological well-being in people with T1DM,over 60%of individuals with T1DM do not exercise regularly.It is,therefore,crucial to devise approaches to motivate patients with T1DM to exercise,to adhere to a training program,and to inform them of its specific characteristics(e.g.,exercise mode,intensity,volume,and frequency).Moreover,given the metabolic alterations that occur during acute bouts of exercise in T1DM patients,exercise prescription in this population should be carefully analyzed to maximize its benefits and to reduce its potential risks.

The effects of plyometric jump training on physical fitness attributes in basketball players:A meta-analysis`

Background:There is a growing body of experimental evidence examining the effects of plyometric jump training(PJT)on physical fitness attributes in basketball players;however,this evidence has not yet been comprehensively and systematically aggregated.Therefore,our objective was to meta-analyze the effects of PJT on physical fitness attributes in basketball players,in comparison to a control condition.Methods:A systematic literature search was conducted in the databases PubMed,Web of Science,and Scopus,up to July 2020.Peer-reviewed controlled trials with baseline and follow-up measurements investigating the effects of PJT on physical fitness attributes(muscle power,i.e.,jumping performance,linear sprint speed,change-of-direction speed,balance,and muscle strength)in basketball players,with no restrictions on their playing level,sex,or age.Hedge’s g effect sizes(ES)were calculated for physical fitness variables.Using a random-effects model,potential sources of heterogeneity were selected,including subgroup analyses(age,sex,body mass,and height)and single training factor analysis(program duration,training frequency,and total number of training sessions).Computation of metaregression was also performed.Results:Thirty-two studies were included,involving 818 total basketball players.Significant(p<0.05)small-to-large effects of PJT were evident on vertical jump power(ES=0.45),countermovement jump height with(ES=1.24)and without arm swing(ES=0.88),squat jump height(ES=0.80),drop jump height(ES=0.53),horizontal jump distance(ES=0.65),linear sprint time across distances≤10 m(ES=1.67)and>10 m(ES=0.92),change-of-direction performance time across distances≤40 m(ES=1.15)and>40 m(ES=1.02),dynamic(ES=1.16)and static balance(ES=1.48),and maximal strength(ES=0.57).The meta-regression revealed that training duration,training frequency,and total number of sessions completed did not predict the effects of PJT on physical fitness attributes.Subgroup analysis indicated greater improvements in older compared to younger players in horizontal jump distance(>17.15 years,ES=2.11;≤17.15 years,ES=0.10;p<0.001),linear sprint time>10 m(>16.3 years,ES=1.83;≤16.3 years,ES=0.36;p=0.010),and change-of-direction performance time≤40 m(>16.3 years,ES=1.65;≤16.3 years,ES=0.75;p=0.005).Greater increases in horizontal jump distance were apparent with>2 compared with≤2 weekly PJT sessions(ES=2.12 and ES=0.39,respectively;p<0.001).Conclusion:Data from 32 studies(28 of which demonstrate moderate-to-high methodological quality)indicate PJT improves muscle power,linear sprint speed,change-of-direction speed,balance,and muscle strength in basketball players independent of sex,age,or PJT program variables.However,the beneficial effects of PJT as measured by horizontal jump distance,linear sprint time>10 m,and change-of-direction performance time≤40 m,appear to be more evident among older basketball players.

Evolution of the electrical contact of dynamic pantograph–catenary system

A good contact between the pantograph and catenary is critically important for the working reliability of electric trains, while the basic understanding on the electrical contact evolution during the pantograph--catenary system working is still ambiguous so far. In this paper, the evolution of electric contact was studied in respects of the contact resistance, temperature rise, and microstructure variation, based on a home-made pantograph-catenary simulation system. Pure carbon strips and copper alloy contact wires were used, and the experimental electrical current, sliding speed, and normal force were set as 80 A, 30 km/h, and 80 N, respectively. The contact resistance presented a fluctuation without obvious regularity, concentrating in the region of 25 and 50 mf~. Temperature rise of the contact point experienced a fast increase at the first several minutes and finally reached a steady state. The surface damage of carbon trips in microstructure analysis revealed a complicated interaction of the sliding friction, joule heating, and arc erosion.

Comparison of blood flow restriction training and conventional resistance training for the improvement of sarcopenia in the older adults:A systematic review and meta-analysis

Age-related sarcopenia places a tremendous burden on healthcare providers and patients'families.Blood flow restriction(BFR)training may be a promising treatment to bring sarcopenia down,and it offers numerous advantages over traditional resistance training.The purpose of this review was to compare the effects of BFR training and conventional resistance training on clinically delayed sarcopenia in the elderly.Databases such as PubMed,Web of Science,Embase,and Science Direct were searched to identify eligible studies;blinded data extraction was performed to assess study quality,and conflicts were submitted to third parties.Someone made the decision.One author used Review Manager(RevMan)5.4 and compared it with data obtained by another author for this purpose.A total of 14 studies met the inclusion criteria for this review.The funnel plots of the studies did not show any substantial publication bias.Low-load blood flow restriction(LL-BFR)had no significant effect on muscle mass compared with high-load resistance training(HL-RT)(p=0.74,SMD=0.07,95%CI:0.33 to 0.46)and LL-BFR had a significant effect on muscle strength compared with HL-RT(p=0.03,Z=2.16,SMD=-0.34,95%CI:0.65 to-0.03).LL-BFR showed a slight effect on mass compared to LL-RT(p=0.26,SMD=0.25,95%CI:0.19 to 0.69).Sensitivity analysis produced a nonsignificant change,suggesting that the results of this study are reasonable.In conclusion,the data suggest the possibility that BFR training improves age-related sarcopenia.

Effect of Tai Chi and Resistance Training on Cancer-Related Fatigue and Quality of Life in Middle-Aged and Elderly Cancer Patients

Objective:To study the effect of Tai Chi(TC)and resistance training(RT)with different intensity on the cancer-related fatigue(CRF)and quality of life(QoL)of middle-aged and elderly cancer patients.Methods:Totally 120 cancer patients were enrolled and randomly assigned to 4 groups by a random number table,including TC group,high-intensity 60%one repetition maximum(1-RM)RT group(HIRT),low-intensity(30%1-RM)RT group(LIRT)and control group,30 patients in each group.Participants in the TC group received 24-form simplified Yang-style TC training at a frequency of 40 min per day,3 days per week for 12 weeks.Patients in the two RT groups received 10 sessions,6 designated movements per day,3 days per week for 12 weeks.The 1-RM of 6 muscle groups,fat mass(FM),lean body mass(LBM),along with the scores of Brief Fatigue Inventory(BFI),QoL questionnaire for Chinese cancer patients receiving chemobiotherapy(QLQ-CCC),Generalized Anxiety Disorder-7(GAD-7),Patient Health Questionnaire-9(PHQ-9)and Pittsburgh Sleep Quality Index(PSQI)were measured before and after training.The adverse effect was also observed.Results:After 12-week intervention,patients in both TC and RT groups showed significant improvements in CRF and QLQ-CCC compared to pre-treatment(P<0.05).Compared with the LIRT and TC groups,patients in the HIRT group improved more significantly in increasing muscle strength and LBM,and reducing in FM(P<0.05).Patients in the TC group significantly increased in lower limb muscle strength compared with the LIRT group(P<0.05).In addition,patients in the TC group showed more significant improvements in scores of GAD-7,PHQ-9 and PSQI than 2 RT groups(P<0.05).Conclusions:TC and RT,both low-and high-intensity training,can significantly increase muscle strength,reduce CRF and improve QoL in the middle-aged and elderly cancer patients.TC has a better effect than RT in terms of sleep quality and mental health.The long-term application is needed to substantiate the effect of TC as an alternative exercise in cancer patients.

The Sensitivity of the Critical Resistance Model to Detect Sex-Related Differences in Fatigue During Submaximal Muscular Contractions

Purpose Critical resistance(CR)is a fatigue threshold that,theoretically,estimates the highest sustainable resistance for repeated skeletal muscle contractions.Men are typically more susceptible to fatigue than women during sustained muscular contractions.Therefore,the purpose of this study was to compare the CR between men and women to determine the sensi-tivity of the CR model to detect sex-related differences in fatigue at submaximal intensities.Methods Ten men and 10 women completed one-repetition maximum(1RM)testing for the deadlift and repetitions to failure at 50%,60%,70%,and 80%of 1RM for the determination of CR.Repetitions to failure were then performed at the estimated CR.Results The men had a greater absolute 1RM(168±27 kg vs.115±11 kg)and CR(62±14 kg vs.48±6 kg),but a lower relative CR(percent of 1RM;37±6%vs.41±2%)and completed fewer repetitions at CR(45±14 repetitions vs.58±12 repetitions)compared to the women.Conclusions The CR model was sensitive to detect sex-related differences in fatiguing muscular contractions of the dead-lift.In addition,the men were more susceptible to fatigue than the women during performance of submaximal muscular contractions at CR,which may be related to sex-dependent physiological responses during fatiguing muscular contractions.