Effects of combined muscle power and endurance training with different volumes on functional and hemodynamic parameters in previously trained older adults.

BACKGROUND: To promote optimal neuromuscular and cardiovascular gains in older adults, it seems crucial to investigate the effects of different combined training volumes in this population. Thus, the present study aimed to compare the effects of combined muscle power training (MPT) and endurance training (ET) with different volumes on functional and hemodynamic parameters in previously trained older adults. METHODS: Twenty-five older adults were randomly assigned to either the lower-volume group (LVG; n = 13) or the higher-volume group (HVG; n = 12). In the LVG, participants performed 1 set of 6 repetitions for each exercise, followed by 10 min of walking exercise. In the HVG, participants performed 2 sets of 6 repetitions for each exercise, followed by 20 min of walking exercise. Lift from the ventral decubitus position (LPDV), timed up-and-go (TUG), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were assessed before and after 8 weeks. RESULTS: Significant increases in LPDV test occurred in both groups after 8 weeks (p < 0.05). Additionally, significant improvements in TUG performance occurred in both groups from week 0 to week 8 (p < 0.05). However, no significant changes were observed between groups in functional parameters (p > 0.05). SBP and DBP remain unchanged (p > 0.05) in both groups over the experimental period. CONCLUSIONS: These findings indicate that lower-volume and higher-volume of combined MPT and ET promoted improvements in functional parameters. This study has an important practical application, as it indicates that regardless of the volume (lower or higher), comparable improvements are observed in functional parameters in previously trained older adults.

Effects of Dancing Associated With Resistance Training on Functional Parameters and Quality of Life of Aging Women: A Randomized Controlled Trial.

The purpose of the present study was to evaluate the effects of a dance intervention associated with resistance training or health education program on functional paramaters and quality of life of aging women. Thirty-six women were allocated to dance plus resistance training group (D + RT) or dance plus health education group (D + HE). Both interventions lasted 8 weeks and were performed twice a week. Dance sessions lasted 60 min. Resistance training was composed by two to three sets of 10-15 repetitions in five exercises. Improvements were found in 30-s chair stand (D + RT: 6 ± 1 repetitions; D + HE: 7 ± 1 repetitions), 30-s arm curl (D + RT: 7 ± 1 repetitions; D + HE: 7 ± 1 repetitions), 6-min walk (D + RT: 43 ± 12 m; D + HE: 55 ± 12 m), timed up and go (D + RT: -1.1 ± 0.3 s; D + HE: -1.4 ± 0.2 s), and psychological domain of quality of life (D + RT: 6 ± 2%; D + HE: 5 ± 3%), with no difference between groups. Both groups improve functional parameters and quality of life of aging women.

Acute Blood Pressure Response to High- and Moderate-Speed Resistance Exercise in Older Adults With Hypertension.

An increase in blood pressure (BP) occurs during resistance exercise; attention to this response may be necessary in older individuals with hypertension. We compared the BP responses following high- (HSRE) and moderate-speed resistance exercise (MSRE) (4 × 8 repetitions at 60% one-repetition maximum) and control protocol in 15 older adults with hypertension. HSRE and MSRE increased systolic BP (SBP) by the end of each set compared with preexercise and control protocol. Immediately after the fourth set, a higher SBP was observed in MSRE than HSRE (147 ± 14 vs. 141 ± 12 mmHg; p = .01). Taking an exploratory analysis of the individual response, we observed that MSRE resulted in greater mean changes and number of SBP exposures to values ≥150 mmHg (22-fold) than HSRE (10-fold). Diastolic BP increased (p < .05) with exercise, but only MSRE increased compared with the control condition (p < .05). HSRE may be an alternative for individuals in which SBP peak should be avoided.

Acute effects of body-weight resistance exercises on blood pressure and glycemia in middle-aged adults with hypertension.

OBJECTIVE: The purpose of the present study was to evaluate the acute effects of single session of body-weight resistance exercises on blood pressure (BP) and glycemia in middle-aged adults with hypertension. METHODS: Twenty-three participants took part in this trial with crossover design and performed two experimental sessions in a random order: Body-weight resistance exercise session (BWR) and a control session without exercise. BWR was composed of four exercises: inverted row, squat, , and sit-ups. The participants performed 3 sets of 30 s, in which they were instructed to perform as much repetitions as possible and as fast as possible. After each session, BP and glycemia were measured continuously for 60 min. RESULTS: Systolic BP decreased after BWR when compared with control at post 45': -7 (95%CI:-11 to -2) mmHg, p = .003 and post60': -7 (95%CI:-12 to -3) mmHg, p = .003. Diastolic BP decreased after BWR when compared with control at post 15': -6 (95%CI:-9 to -3) mmHg, p < .001; post 30': -6 (95%CI:-9 to -2) mmHg, p = .001; post45': -5 (95%CI:-9 to -2) mmHg, p = .005; and post60': -6 (95%CI: -8 to -3) mmHg, p < .001. No significant difference was found in glycemia between BWR and control sessions. CONCLUSION: BWR acutely reduces BP in middle-aged adults with hypertension without effects on usual glycemia responses. This alternative form of resistance training could facilitate access, adherence, and reduce health costs related to exercise programs.

Adaptations in mechanical muscle function, muscle morphology, and aerobic power to high-intensity endurance training combined with either traditional or power strength training in older adults: a randomized clinical trial.

PURPOSE: There is a lack of information on the effects of power training (PT) as an alternative to traditional strength training (TST) during concurrent training (CT) in older individuals. This study aimed to verify the neuromuscular adaptations that occurred following 16-week interventions with two CT models in older men: high-intensity interval training (HIIT) combined with either TST or PT. METHODS: Thirty-five older men (65.8 ± 3.9 years) were randomly assigned into one of two training groups CTS: TST + HIIT (n = 18) or CTP: PT + HIIT (n = 17). CTS performed resistance training at intensities ranging from 65 to 80% of 1 RM at slow controlled speed, whereas CTP trained at intensities ranging from 40 to 60% of 1 RM at maximal intentional speed. Lower body one-repetition maximum (1 RM), isometric rate of force development (RFD), countermovement jump (CMJ) muscle power output, quadriceps femoris muscles thickness (QF MT), and peak oxygen uptake (VO2peak) were assessed before training and after 8 and 16 weeks of CT. RESULTS: Groups improved similarly in all primary outcomes (P < 0.05), with mean increases ranging: 1 RM (from 39.4 to 75.8%); RFD (from 9.9 to 64.8%); and CMJ muscle power (from 1.8 to 5.2%). Significant increases (P < 0.05) were observed in all secondary outcomes (QF MT, specific tension and VO2peak) with no differences between groups. CONCLUSION: CT models were effective for improving maximal and explosive force (1 RM, RFD, and CMJ power), QF MT, and VO2peak. Moreover, despite that using lower loading intensities, PT induced similar adaptations to those of TST.

Acute and chronic effects of muscle power training on blood pressure in elderly patients with type 2 diabetes mellitus.

The aim of the present study was to evaluate the effects of 12 weeks of muscle power training (MPT) on casual blood pressure (BP) (before and after each training session) and resting BP (pre- and post-training program) in type 2 diabetes mellitus (T2DM) elderly.Methods: Twelve T2DM elderly individuals (68.75 ± 7.83 years), non-insulin-dependents participated in the present study and performed the MPT program twice a week. Casual BP was measured before and after training sessions, and resting BP was measured 48 h before the first and 48 h after the last training session.Results: Significant decrease in casual systolic (SBP) (-7.08 ± 4.12 mm Hg [effect size [ES]: -1.42 to -0.11]; p < 0.01) and diastolic (DBP) BP (-3.14 ± 1.24 mm Hg [ES: -1.24 to -0.18]; p > 0.01) was found after training sessions, without significant effect (p > 0.05) of the week along time or casual BP × week interaction. No significant change in resting SBP (-5.08 ± 8.93 mm Hg [ES: -0.41]; p = 0.07) and DBP (0.47 ± 6.06 mm Hg [ES: +0.11]; p = 0.79) was found.Conclusion: MPT was able to reduce casual BP after training sessions. However, there was no significant reduction in resting BP after MPT. Nevertheless, although not statistically significant, there were important clinical reductions in resting SBP in T2DM elderly patients.

Effects and prevalence of responders after a multicomponent intervention on cardiometabolic risk factors in children and adolescents with overweight/obesity: Action for health study.

This study aimed to verify the effect of a multicomponent intervention on cardiometabolic risk factors (CMRF), and to determine the prevalence of responders on CMRF among children and adolescents with overweight/obesity. This is a quasi-experimental study, developed with 35 children and adolescents with overweight/obesity (control group (CG) = 18; intervention group (IG) = 17), aged between 7 and 13 years. Participants in IG underwent a multicomponent intervention for 12 weeks. The following variables were evaluated: anthropometric measures, maturational stages and CMRF (body fatness, HOMA-IR, triglycerides, high-density and low-density lipoprotein) (HDL-C, LDL-C), total cholesterol (TC), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and AST/ALT ratio. Mixed analysis of variance and the prevalence of responders were used for statistical analysis. There was a significant time x group interaction on body fatness (p < 0.001), HOMA-IR (p = 0.01), HDL-C (p < 0.001), LDL-C (p = 0.009) and TC (p < 0.001). The prevalence of responders for CMRF in IG and CG was respectively: body fatness (47%; 0%; p = 0.04), HOMA-IR (58.8%; 16.6%; p = 0.04); triglycerides (17.6%; 5.5%; p = 0.31); HDL-C (76.4%; 5.5%; p = 0.01), LDL-C (35.3%; 5%; p = 0.08), TC (64.7%; 5%; p = 0.01), AST (5.8%; 0%; p = 0.87), ALT (29.4%; 11.1%; p = 0.24) and AST/ALT ratio (24.4%; 22.2%; p = 0.67). Multicomponent intervention induced positive changes on CMRF along with a higher prevalence of positive adaptations in IG than the CG in some of the cardiometabolic outcomes assessed.

Effects of resistance training, detraining, and retraining on strength and functional capacity in elderly.

BACKGROUND: The interruption of training (detraining) results in loss of the gains acquired. Partial retention could occur after detraining, and variation in training stimuli may optimize retraining adaptations. AIM: To evaluate the effect of a resistance-retraining program on strength and functional capacity performance after a detraining period. METHODS: Ten elderly men and women (63-68 years) completed 12 weeks of training, 16 weeks of detraining, and 8 weeks of retraining. One-repetition maximum (1-RM) at 45° leg press, maximum isometric knee extension torque, rate of torque development (RTD), 30-s sit-to-stand, timed up and go, and stair ascent and descent tests were assessed. RESULTS: The 1-RM increased after training (p < 0.01) and remained higher after a detraining period when compared to pre-training (p < 0.01). Post-retraining values were not different from post-training period (p > 0.05). For RTD and 30-s sit-to-stand, there was an increase after retraining when compared to pre-training values (p < 0.05). For timed up and go and stair ascent and descent, reductions were observed between pre-training and post-training periods (p < 0.05), only timed up and go increased after the detraining period (p < 0.01). DISCUSSION: After 16 weeks of detraining, the maximum strength did not return to baseline levels, and a retraining with explosive strength exercise sessions can recover maximum strength gains, RTD, and functional capacity at the same level obtained after a detraining period. CONCLUSIONS: The inclusion of an explosive strength session in retraining period improves RTD and 30-s sit-to-stand performance and can accelerate the recovery of strength after a detraining period.

Concurrent Training and Detraining: brief Review on the Effect of Exercise Intensities.

Concurrent resistance and aerobic training (CT) has been applied to optimize both strength and aerobic performance. However, it should be carefully prescribed, as there are some factors, as the training intensity, which have strong influence on training adaptations. Thus, we conducted a systematic review to analyze the scientific evidence regarding aerobic and resistance exercise intensities during CT and their effect on performance outcomes. The effects of exercise intensity on a subsequent detraining period were also assessed. Nine studies met the inclusion criteria, the risk of bias was assessed, and the percentage of changes and effect sizes were quantified. CT improved running times (10 m, 30 m and 10 km) and strength performance (one-repetition maximum, countermovement jump) regardless of exercise intensity used (4-47%, ES=0.4-2.8). Nevertheless, higher aerobic training intensities (≥ lactate threshold intensity) resulted in higher aerobic gains (5-10%, ES=0.3-0.6), and greater neuromuscular adaptations were found when higher resistance loads (≥ 70% of maximal strength) were used (10-14%, ES=0.4-1.3). Most training-induced gains were reversed after 2-4 weeks of detraining. Although further research is needed, it seems that higher intensities of aerobic or resistance training induce greater aerobic or neuromuscular gains, respectively. Nevertheless, it seems that higher resistance training loads should be combined with lower aerobic training intensities for increased strength gains and minimal losses after detraining.

Benefits of resistance training in physically frail elderly: a systematic review.

AIM: Exercise is one of the most important components in frailty prevention and treatment. Therefore, we systematically reviewed the effect of resistance training (RT) alone or combined with multimodal exercise intervention on muscle hypertrophy, maximal strength, power output, functional performance, and falls incidence in physically frail elderly. METHODS: MEDLINE, Cochrane CENTRAL, PEDro, and SPORTDiscus databases were searched from 2005 to 2017. Studies must have mentioned the effects of RT (i.e., included or not in multimodal training) on at least one of the following parameters: muscle mass, muscle strength, muscle power, functional capacity, and risk of falls in frail elderly. RESULTS: The initial search identified 371 studies and 16 were used for qualitative analysis for describing the effect of strength training performed alone or in a multimodal exercise intervention. We observed that RT alone or in a multimodal training may induce increases of 6.6-37% in maximal strength; 3.4-7.5% in muscle mass, 8.2% in muscle power, 4.7-58.1% in functional capacity and risk of falls, although some studies did not show enhancements. CONCLUSION: Frequency of 1-6 sessions per week, training volume of 1-3 sets of 6-15 repetitions and intensity of 30-70%1-RM promoted significant enhancements on muscle strength, muscle power, and functional outcomes. Therefore, in agreement with previous studies, we suggest that supervised and controlled RT represents an effective intervention in frailty treatment.

Effectiveness of Multimodal Training on Functional Capacity in Frail Older People: A Meta-Analysis of Randomized Controlled Trials.

In this meta-analysis, we investigated the effect of resistance training (RT) alone or included in a multimodal training on physical frailty outcomes, and whether different variables of RT prescription affect these outcomes. We identified 15 relevant studies searching through MEDLINE, Cochrane Central Register of Controlled Trials, SPORTDiscus, and PEDro database. Postintervention standardized mean difference scores were computed and combined using fixed effects meta-analysis. Analyses have shown positive effects of interventions on maximum strength, gait speed, and Timed Up and Go test. Further analyses have shown significant greater effect of shorter periods on maximum strength. Regarding RT prescription, percentage of one-repetition maximum showed significant effect on physical variables, whereas RT based on rate of perceived effort presented lower effect in the Timed Up and Go test. Although multimodal training is an effective intervention to increase physical capacity, caution should be taken regarding the period and the method to control RT intensity to optimize enhancements in frail older people.

Rating of perceived exertion in maximal incremental tests during head-out water-based aerobic exercises.

The present study aimed to assess the relationship between rating of perceived exertion (RPE) and percentage of peak oxygen uptake ([Formula: see text]) during three head-out water-based aerobic exercises. In addition, the RPE at the second ventilatory threshold (VT2) was also compared among them. Twenty young women performed head-out water-based maximal tests for the exercises stationary running (SR), frontal kick (FK) and cross-country skiing (CCS). RPE was monitored during the tests and the values corresponding to VT2 and training zones corresponding to 50-59%, 60-69%, 70-79%, 80-89% and [Formula: see text] were determined. Regression analysis, descriptive statistics and ANOVA with repeated measures were used. Significant relationships were observed between the RPE and [Formula: see text] (r = 0.858-0.893; P < 0.001) for all head-out water-based aerobic exercises. Average RPE ranged from 12.1-12.7 in the training zone corresponding to 50-59%, from 13.7-14.8 to 60-69%, from 15.8-16.4 to 70-79%, from 17.3-18.1 to 80-89% and from 18.5-18.9 to [Formula: see text]. No significant differences were found among the three head-out water-based aerobic exercises at VT2 (P > 0.05; SR: 16.1 ± 0.9, FK: 16.7 ± 1.5, CCS: 15.9 ± 1.3). The results support the use of RPE to control the relative intensity of training during head-out water-based aerobic exercises and indicate values near to 16-17 when targeting VT2 intensity for young women.

Vertical ground reaction force responses to different head-out aquatic exercises performed in water and on dry land.

The purpose was to analyse the vertical ground reaction forces (Fz) of head-out aquatic exercises [stationary running (SR), frontal kick (FK), cross-country skiing (CCS), jumping jacks (JJ), adductor hop (ADH) and abductor hop (ABH)] at two cadences in both aquatic and dry land environments. Twelve young women completed two sessions in each environment, each consisting of three exercises performed at two cadences (first and second ventilatory thresholds - C1 and C2, respectively). Two-way and three-way repeated measures analysis of variance were used to the statistical analysis. The results showed that the peak Fz and impulse were significantly lower in the aquatic environment, resulting in values from 28.2% to 58.5% and 60.4% to 72.8% from those obtained on dry land, respectively. In the aquatic environment, the peak Fz was lower and the impulse was higher at the C1 than at the C2. Furthermore, it was observed that SR and FK (0.9-1.1 BW) elicited a significantly higher peak Fz values compared to the ADH and JJ exercises (0.5-0.8 BW). It can be concluded that the aquatic environment reduces the Fz during head-out aquatic exercises. It should be noted that its magnitude is also dependent on the intensity and the identity of the exercise performed.

Water-based exercise and quality of life in women: the role of depressive symptoms.

Several studieshave evaluated the relation of exercise to quality of life (QoL). To our knowledge, no study has evaluated the relation of water-based exercise to depressive symptoms and QoL, or the association between improvement in QoL and depressive symptoms in healthy women. The purpose of this study was to evaluate the association of water-based exercise with changes in QoL. Forty-seven women performed water-based combined exercise for 12 weeks. All participants improved in the physical and psychological domains of QoL. Decreases in depressive symptoms and improvements in maximal strength and aerobic capacity were found for all participants. A regression model revealed that depressive symptoms were associated with improvements in physical and psychological domains of QoL. The results showed that moderate intensity, water-based exercise improved physical and psychological domains of QoL, depressive symptoms, aerobic capacity, and muscular strength of women. Furthermore, the improvement in physical and psychological domains of QoL appeared to be mediated by the antidepressant effects of exercise, but not by changes in aerobic capacity or muscular strength.

Effects of social distancing provoked by COVID-19 pandemic in the functional capacity and cognitive function in nonagenarians and centenarians.

INTRODUCTION: Due to the rapid advance of coronavírus SARS-CoV-2 (COVID-19) pandemic in 2020, social distancing was the main way to reduce the transmission of the virus. Although this measure was efficient and necessary, the social distancing had severe consequences for physical function, mainly in older individuals. Thus, the aim of this study was to investigate the effects of social distancing in the functional and cognitive capacity of community-dwelling oldest-old adults. METHODS: The present study is part of a larger prospective cohort study. Fifteen participants aged 90 years old or older were assessed in the 8-foot-timed-up-and-go test (8-footTUG), sit-to-stand-up test (STS), handgrip strength test (HGS), Mini Mental State Examination (MMSE), Katz Index and Lawton Scale before and after one year of social distancing. RESULTS: A significant worsening in the 8-footTUG and MMSE score was observed, while there were no significant changes in the other variables. When analyzing the decreases in relation to previous functional capacity, it was observed that individuals categorized as dependent by STS cut-off points had the worst decreases in functional capacity. CONCLUSION: The social distancing provoked by COVID-19 pandemic negatively affected the 8-footTUG and cognition. Moreover, individuals dependents showed greater decline in their functional capacity.

Acute effects of different proprioceptive neuromuscular facilitation stabilization techniques on the balance of elderly women.

AIM: To compare the acute effects of rhythmic stabilization (RS) and stabilizer reversal (SR) techniques of PNF on the balance of sedentary elderly women. METHODS: Women aged (≥70) were allocated into three groups: RS, SR and control (CR). The experimental groups (RS and SR) performed balance exercises with the addition of rhythmic stabilization techniques (RS group) or with stabilizers reversal (SR group) for 15 min. The CR group performed the exercises without adding the PNF stabilization techniques. Participants performed the Time Up and Go (TUG) test, the Functional Reach Test (FRT) and static and dynamic stabilometry pre and post intervention. Kruskal-Wallis and Mann-Whitney tests were used for comparison between groups and post hoc analysis, respectively, with p ≤ 0.05. For the effect size measurements, the r for Wilcoxon and Mann-Whitney signal were used. RESULTS: For functional tests intra-group analysis, a reduction in TUG time and an increase in FRT range (p ≤ 0.05) were observed in RS e SR groups. Stabilometry analysis showed a significant difference only for the RS group, with reduced average velocity of the centre of pressure (COP), and an increased in the left foot pressure. CONCLUSIONS: A single RS or SR session reduced the TUG time and the range distance in the FRT in elderly women. A single session of the RS technique was also able to reduce the mean velocity of the COP and the maximum pressure on the left foot. IMPACT: This study shows an easy-to-apply methods without additional materials that can help prevent falls in the elderly.

Chronic Effects of Different Intensities of Power Training on Neuromuscular Parameters in Older People: A Systematic Review with Meta-analysis.

BACKGROUND: Power training (PT) has been shown to be an effective method for improving muscle function, including maximal strength, measured by one-repetition maximum (1RM), and power output in older adults. However, it is not clear how PT intensity, expressed as a percentage of 1RM, affects the magnitude of these changes. The aim of this systematic review (International prospective register of systematic reviews-PROSPERO-registration: CRD42022369874) was to summarize the evidence from randomized clinical trials (RCT) assessing the effects of low-intensity (≤ 49% of 1RM) and moderate-intensity (50-69% of 1RM) versus high-intensity (≥ 70% of 1RM) PT on maximal power output and maximal strength in older adults. METHODS: We included RCTs that examined the effects of different intensities of power training on maximum strength and power output in older people. The search was performed using PubMed, LILACS, Embase, and Scopus. Methodological quality was assessed using the preferred reporting items for systematic reviews and meta-analyses (PRISMA 2020 statement checklist), and the quality of evidence was determined using the PEDro scale. Data were analyzed using standardized mean differences (SMD) with a 95% confidence interval (CI), and random effects models were used for calculations. A significance level of p ≤ 0.05 was accepted. RESULTS: Three RCTs assessing 179 participants, all of high methodological quality, were included. There were no significant differences between different PT intensities in terms of power output gains for leg press [SMD = 0.130 (95% CI - 0.19, 0.45), p = 0.425] and knee extension exercises [SMD: 0.016 (95% CI - 0.362, 0.395), p = 0.932], as well as leg press 1RM increases [SMD: 0.296 (95% CI - 0.03, 0.62); p = 0.072]. However, high-intensity PT (70-80% of 1RM) was significantly more effective than low-intensity PT in increasing 1RM for knee extension exercise [SMD: 0.523 (95% CI 0.14, 1.91), p = 0.008]. CONCLUSIONS: PT performed at low-to-moderate intensities induces similar power gains compared to high-intensity PT (70-80% of 1RM) in older adults. Nonetheless, the influence of PT intensity on lower-limb strength gains seems to be dependent on the assessed exercise. Cautious interpretation is warranted considering the inclusion of only three studies.

Are dose-response relationships of resistance training reliable to improve functional performance in frail and pre-frail older adults? A systematic review with meta-analysis and meta-regression of randomized controlled trials.

This systematic review with meta-analyses investigates the impact of resistance training (RT), using meta-regressions, on functional performance in frail and pre-frail adults aged ≥ 65 years to determine the key variables of RT. Ten randomized controlled trials involving 1303 participants were analyzed. Five studies assessed habitual walking speed (HWS), three studies evaluated performance in the timed-up-and-go test (TUG), three studies evaluated performance in the Short Physical Performance Battery (SPPB), and three studies assessed performance in the sit-to-stand test (STS). RT alone improved STS time and SPPB scores in frail and pre-frail older adults. RT improved STS performance (Effect Size (ES):- 0.536; 95% CI - 0.874 to - 0.199; p = .002) and led to a 2.261-point increase in SPPB performance (ES:1.682; 95% CI 0.579-2.786; p = .003). At least two weekly training sessions are required to increase SPPB scores, and three sessions seem to optimize the improvements. Higher training volume per exercise and volume per session reduce the gains in SPPB performance. We did not observe any association between different doses of RT and STS time improvements. RT alone positively influenced TUG performance only in community-dwelling older frail and pre-frail adults but not in institutionalized older individuals. RT alone did not improve the HWS compared to the non-active control group.

Low Pre-Season Hamstring-to-Quadriceps Strength Ratio Identified in Players Who Further Sustained In-Season Hamstring Strain Injuries: A Retrospective Study from a Brazilian Serie A Team.

A common pre-season injury prevention assessment conducted by professional football clubs is the hamstring-to-quadriceps (H:Q) strength ratio calculated by peak torque (PT). However, it is debatable whether players that present low pre-season H:Q ratios are more susceptible to further sustaining in-season hamstring strain injuries (HSI). Based upon retrospective data from a Brazilian Serie A football squad, a particular season came to our attention as ten out of seventeen (~59%) professional male football players sustained HSI. Therefore, we examined the pre-season H:Q ratios of these players. H:Q conventional (CR) and functional (FR) ratios, and the respective knee extensor/flexor PT from the limbs of players further sustaining in-season HSI (injured players, IP) were compared to the proportional number of dominant/non-dominant limbs from uninjured players (UP) in the squad. FR and CR were ~18-22% lower (p < 0.01), whereas quadriceps concentric PT was ~25% greater for IP than UP (p = 0.002). Low scores of FR and CR were correlated (p < 0.01) with high levels of quadriceps concentric PT (r = -0.66 to -0.77). In conclusion, players who sustained in-season HSI had lower pre-season FR and CR compared to UP, which appears to be associated with higher levels of quadriceps concentric torque than hamstring concentric or eccentric torque.