Dynamic circadian fluctuations of glycemia in patients with type 2 diabetes mellitus

BACKGROUND

Diabetes mellitus (DM) has glucose variability that is of such relevance that the appearance of vascular complications in patients with DM has been attributed to hyperglycemic and dysglycemic events. It is known that T1D patients mainly have glycemic variability with a specific oscillatory pattern with specific circadian characteristics for each patient. However, it has not yet been determined whether an oscillation pattern represents the variability of glycemic in T2D. This is why our objective is to determine the characteristics of glycemic oscillations in T2D and generate a robust predictive model.

RESULTS

Showed that glycosylated hemoglobin, glycemia, and body mass index were all higher in patients with T2D than in controls (all p < 0.05). In addition, time in hyperglycemia and euglycemia was markedly higher and lower in the T2D group (p < 0.05), without significant differences for time in hypoglycemia. Standard deviation, coefficient of variation, and total power of glycemia were significantly higher in the T2D group than Control group (all p < 0.05). The oscillatory patterns were significantly different between groups (p = 0.032): the control group was mainly distributed at 2-3 and 6 days, whereas the T2D group showed a more homogeneous distribution across 2-3-to-6 days.

CONCLUSIONS

The predictive model of glycemia showed that it is possible to accurately predict hyper- and hypoglycemia events. Thus, T2D patients exhibit specific oscillatory patterns of glycemic control, which are possible to predict. These findings may help to improve the treatment of DM by considering the individual oscillatory patterns of patients.

Characterizing the interindividual postexercise hypotension response for two order groups of concurrent training in patients with morbid obesity

Background: Postexercise hypotension (PEH) is a common physiological phenomenon occurring immediately after endurance training (ET), resistance training (RT), and ET plus RT, also termed concurrent training (CT); however, there is little knowledge about the interindividual and magnitude response of PEH in morbidly obese patients.

Aim: The aims of this study were (1) to investigate the effect of CT order (ET + RT vs. RT + ET) on the blood pressure responses; 2) characterize these responses in responders and nonresponders, and 3) identify potential baseline outcomes for predicting blood pressure decreases as responders.

Methods: A quasi-experimental study developed in sedentary morbidly obese men and women (age 43.6 ± 11.3 years; body mass index [BMI] ≥40 kg/m²) was assigned to a CT group of ET plus RT (ET + RT; n = 19; BMI 47.8 ± 16.7) or RT plus ET order group (RT + ET; n = 17; BMI 43.0 ± 8.0). Subjects of both groups received eight exercise sessions over four weeks. Primary outcomes include systolic (SBP), diastolic (DBP), mean arterial pressure [MAP], heart rate at rest [HR], and pulse pressure [PP] measurements before and after 10 min post-exercise. Secondary outcomes were other anthropometric, body composition, metabolic, and physical fitness parameters. Using the delta ∆SBP reduction, quartile categorization (Q) in “high” (Rs: quartile 4), “moderate” (MRs: quartile 3), “low” (LRs: quartile 2), and “nonresponders” (NRs: quartile 1) was reported.

Results: Significant pre–post changes were observed in ET + RT in session 2 for SBP (131.6 vs. 123.4 mmHg, p = 0.050) and session 4 (131.1 vs. 125.2 mmHg, p = 0.0002), while the RT + ET group showed significant reductions in session 4 (134.2 vs. 125.3 mmHg, p < 0.001). No significant differences were detected in the sum of the eight sessions for SBP (∑∆SBP) between ET + RT vs. RT + ET (−5.7 vs. −4.3 mmHg, p = 0.552). Interindividual analyses revealed significant differences among frequencies comparing Q1 “NRs” (n = 8; 22.2%), Q2 “LRs” (n = 8; 22.2%), Q3 “MRs” (n = 9; 25.0%), and Q4 “HRs” (n = 11; 30.5%), p < 0.0001. Quartile comparisons showed significant differences in SBP changes (p = 0.035). Linear regression analyses revealed significant association between ∑∆SBP with body fat % (β –3.826, R² 0.211 [21.1%], p = 0.031), skeletal muscle mass [β –2.150, R² 0.125 (12.5%), p = 0.023], fasting glucose [β 1.273, R² 0.078 (7.8%), p = 0.003], triglycerides [β 0.210, R² 0.014 (1.4%), p = 0.008], and the 6-min walking test [β 0.183, R² 0.038 (3.8%), p = 0.044].

Conclusion: The CT order of ET + RT and RT + ET promote a similar ‘magnitude’ in the postexercise hypotensive effects during the eight sessions of both CT orders in 4 weeks of training duration, revealing “nonresponders” and ‘high’ responders that can be predicted from body composition, metabolic, and physical fitness outcomes.

Effects of six weeks outdoor versus treadmill running on physical fitness and body composition in recreationally active young males: a pilot study

Background

Running as exercise may be performed either on an outdoor surface or treadmill surface. However, previous research has indicated that the nature of both the surfaces differ significantly and therefore the training outcomes from running in these surfaces may also vary.

Aim

Therefore, the aim of this pilot study was to compare the effects of 6-weeks of supervised outdoor running (OT) vs treadmill running (TT) on physical fitness and body composition in recreationally active young males.

Methods

Participants (age: 19.82 ± 1.28 years, height: 172.6 ± 4.9 cm, body mass: 64.3 ± 8.7 kg) were randomly assigned to OT (n = 14) or TT (n = 14), and assessed for physical fitness, i.e., 50 m sprint, cardiorespiratory endurance (i.e., 1,600 m run time-trial), standing long jump (SLJ), flexibility (i.e., sit-and-reach test), and upper-body muscle endurance (i.e., push-ups repetitions), alongside body composition, i.e., body mass, body mass index (BMI), fat percentage, fat free mass, and leg skeletal muscle mass (SMM). A two (pre-post intervention) by two (OT, TT) mixed ANOVA analysed exercise-specific effects. For significant group-by-time interactions, Bonferroni adjusted paired (within-group) and independent (between-group comparisons at post) t-tests were used for post-hoc analyses.

Results

Significant time-effect was found in all physical fitness variables (all p < 0.001, η_p ² = 0.67-0.91), body mass (p = 0.23, η_p ² = 0.18), BMI (p = 0.009, η_p ² = 0.24), body fat percentage (p = 0.001, η_p ² = 0.38), and leg SMM (p = 0.002-0.007, η_p ² = 0.25-0.33). Significant group-by-time interaction was found for 50 m sprint (p = < 0.001, η_p ² = 0.74), 1,600 m run (p = 0.001, η_p ² = 0.35), and SLJ (p < 0.001, η_p ² = 0.43), favouring OT. Group-specific post-hoc tests showed improvements in all physical fitness variables after OT (p = < 0.001-0.001, g = 0.69-2.32, %Δ = 3.0-12.4) and TT (p = < 0.001-0.017, g = 0.15-0.65, %Δ = 0.9-11.7), and fat percentage after OT and TT (p = 0.002-0.041, g = 0.14-0.26, %Δ = 4.3-6.0). However, leg SMM decreased in TT (p = 0.001-0.004, g = 0.14-0.15, %Δ = 6.2-6.7).

Conclusions

Both OT and TT improved physical fitness and decreased fat percentage. However, compared to TT, the OT intervention preserved leg SMM and induced greater physical fitness improvements.

Anthropometric Parameters, Physical Activity, Physical Fitness, and Executive Functions among Primary School Children

Physical activity during childhood and adolescence favors brain development and cognitive functioning, particularly the executive functions. This study aimed to assess potential associations between anthropometric parameters, physical activity, physical fitness, and executive functions among elementary school children returning to school after the COVID-19 lockdown in Chile. School-age male and female participants (n = 90; age, 10−12 years) participated in the study. To determine the association between variables, a multivariable linear regression analysis was performed. Higher fat-related anthropometric indexes were associated with lower working memory, cognitive flexibility, planning, and attention (r = −0.55 to −0.22; p = 0.031 to <0.001). In contrast, higher physical activity levels, better sprint performance, higher lower-body muscular power, and greater upper-body muscular strength were associated with better working memory, cognitive flexibility, inhibition, planning, and/or attention (r = 0.19 to −0.54; p = 0.04 to <0.001). Current results consistently suggest the need for adequate levels of physical activity, physical fitness, and anthropometric parameters among the school-age population to promote healthy and adequate executive functions.

Isokinetic force-power profile of the shoulder joint in males participating in CrossFit training and competing at different levels

Background

As participants who engage in CrossFit training and competition perform a large volume of high intensity overhead activities, injuries to the shoulder are one of the most common in this sport. Previous research in other sports has indicated that the isokinetic force power profile of the shoulder joint (IPSJ) rotator muscles may assist in the prediction of shoulder injury.

Aim

Therefore, the objective of this study was to determine the IPSJ in males engaged in CrossFit training at different competitive levels.

Methods

In a cross-sectional study design, participants (age, 24.1 ± 2.7 years) classified as ‘beginner’ (n = 6), ‘intermediate’ (n = 7) or ‘advanced’ (n = 9) provided informed consent to participate in this study. The IPSJ assessment involved rotational and diagonal movements, including internal and external shoulder rotator muscles, at both 180°.s⁻¹ and 300°.s⁻¹. The variables analysed were peak torque/body mass (%), mean power (W) and the external/internal peak torque/body mass ratio (%). A Kruskal–Wallis test was used to compare the IPSJ of the three groups, with Dunn’s test used for post-hoc analysis. The alpha level was set at p < 0.05.

Results

The IPSJ showed greater torque and power values in those who competed at the advanced level as compared to those at a lower competitive level (i.e. intermediate, beginner). This was observed mainly for the internal rotation and internal diagonal movements at both 180°.s⁻¹ and 300°.s⁻¹. However, such differences between competitive levels were, in general, absent for the external rotation and external diagonal movements. Moreover, the participants from the advanced competitive level exhibited an imbalance of peak torque between the muscles responsible for the external–internal rotational and external-internal diagonal movements of the shoulder (i.e. peak torque external/internal ratio <66%), particularly in the dominant shoulder.

Conclusion

These findings suggest greater development of the shoulder internal rotators and a higher probability of shoulder injury in CrossFit athletes at the advanced competitive level. Based on these results, participants engaged in CrossFit training and competition may wish to increase the volume of training for the shoulder external rotator muscles to complement the large increases in shoulder internal rotator strength that occur as a part of their regular training regimes.

Gender differences in blood pressure and body composition in schoolchildren ascendants from Amerindian and European

Background: In spite of there are a wide knowledge of the prevalence of hypertension in adult, there is poor information on schoolchildren of different ethnicity and gender.Aim: To compare the levels of blood pressure and other cardiometabolic risk factors for hypertension between schoolchildren of different gender and ethnicity.Material and methods: In a cross-sectional study, 540 schoolchildren (6-13 years) ascendants from a Chilean public school population were analysed by ethnicity and gender in four groups (Mapuches N = 55; European boys N = 199, and Mapuches N = 64, and European girls N = 222). The study included the measurement of cardiovascular (systolic and diastolic blood pressure) as main outcomes, as well as other cardiovascular (resting heart rate), body composition (body mass, BMI, waist circumference, fat mass, muscle mass), muscle strength (handgrip strength of dominant, non-dominant, and mean handgrip strength) as additional cardiometabolic outcomes.Results: The systolic blood pressure was significantly higher in Mapuches girls 126 ± 4 vs. their European counterparts 119 ± 3 mmHg, P < .002, as well as diastolic blood pressure, was higher in Mapuches girls 82 ± 5 vs. European girls 74 ± 3 mmHg, P < .0001. There were more 'prehypertensive' Mapuches girls 10 (15.6%) vs. European peers 22 (9.9%) at P < .0001, and the 'hypertension' was significantly more prevalent in Mapuches boys 19 (34.5%) vs. European peers 39 (19.4%) at P < .0001, as well as in Mapuches girls 16 (25%) vs. European peers 33 (14.9%) at P < .0001. The 'obesity' was less prevalent in Mapuches 10 (18.2%) vs. European boys 55 (27.4%) at P < .0001. The waist circumference was high in European 74 ± 4 vs. Mapuches 67 ± 6 cm, P < .012 in boys, although, waist circumference was high in Mapuches girls 75 ± 5 vs. European peers 71 ± 3 cm, P < .021. There were higher levels of muscle mass in Mapuches boys 19.5 ± 12 vs. European peers 17.1 ± 4 kg, P < .0001.Conclusion: Mapuches girls show higher levels of systolic and diastolic BP than European girls, Mapuches boys and girls are more hypertensive than European peers, but are less obese than European schoolchildren peers. These cardiometabolic differences that are more detrimental for endemic ethnic Latinoamerican groups are in need to be explored further.

Effects of Progressed and Nonprogressed Volume-Based Overload Plyometric Training on Components of Physical Fitness and Body Composition Variables in Youth Male Basketball Players

ABSTRACT

Palma-Muñoz, I, Ramírez-Campillo, R, Azocar-Gallardo, J, Álvarez, C, Asadi, A, Moran, J, and Chaabene, H. Effects of progressed and nonprogressed volume-based overload plyometric training on components of physical fitness and body composition variables in youth male basketball players. J Strength Cond Res 35(6): 1642-1649, 2021-This study examined the effect of 6 weeks of progressed and nonprogressed volume-based overload plyometric training (PT) on components of physical fitness and body composition measures in young male basketball players, compared with an active control group. Subjects were randomly assigned to a progressed PT (PPT, n = 7; age = 14.6 ± 1.1 years), a non-PPT (NPPT, n = 8, age = 13.8 ± 2.0 years), or a control group (CG, n = 7, age = 14.0 ± 2.0 years). Before and after training, body composition measures (muscle mass and fat mass), countermovement jump with arms (CMJA) and countermovement jump without arms (CMJ), horizontal bilateral (HCMJ) and unilateral jump with right leg (RJ) and left leg (LJ), 20-cm drop jump (DJ20), sprint speed (10 m sprint), and change of direction speed (CODS [i.e., T-test]) were tested. Significant effects of time were observed for muscle and fat mass, all jump measures, and CODS (all p < 0.01; d = 0.37-0.83). Significant training group × time interactions were observed for all jump measures (all p < 0.05; d = 0.24-0.41). Post hoc analyses revealed significant pre-post performance improvements for the PPT (RJ and LJ: ∆18.6%, d = 0.8 and ∆22.7%, d = 0.9, respectively; HCMJ: ∆16.4%, d = 0.8; CMJ: ∆22.4%, d = 0.7; CMJA: ∆23.3%, d = 0.7; and DJ20: ∆39.7%, d = 1.1) and for the NPPT group (LJ: ∆14.1%, d = 0.4; DJ20: ∆32.9%, d = 0.8) with greater changes after PPT compared with NPPT for all jump measures (all p < 0.05; d = 0.21-0.81). The training efficiency was greater (p < 0.05; d = 0.22) after PPT (0.015% per jump) compared with NPPT (0.0053% per-jump). The PPT induced larger performance improvements on measures of physical fitness as compared to NPPT. Therefore, in-season progressive volume-based overload PT in young male basketball players is recommended.

Effects of different resistance training frequencies on body composition and muscular performance adaptations in men

BACKGROUND

The aim of this study was to compare the effects of 8 weeks resistance training (RT) with two sessions versus four sessions per week under volume load-equated conditions on body composition, maximal strength, and explosive actions performance in recreationally trained men.

METHODS

Thirty-five healthy young men participated in the study and were randomly divided into a two sessions per-week RT (RT2, n = 12), four sessions per-week RT (RT4, n = 13) or a control group (CG, n = 10). All subjects were evaluated for thigh, chest and arm circumference, countermovement jump (CMJ), medicine ball throw (MBT), 1-repetition maximum (1RM) leg press, bench press, arm curl, muscular endurance (i.e., 60% of 1RM to failure) for leg press, and bench press at pre, mid (week 4) and post an 8-week training intervention.

RESULTS

A two-way analysis of variance with repeated measures (3 [group] × 3 [time]) revealed that both training groups increased chest and thigh circumferences, strength and explosive actions performance tests in comparison to CG following 8 weeks of training (p = 0.01 to 0.04). Group × time interactions were also noted in 1RM bench press (effects size [ES] = 1.07 vs. 0.89) and arm curl (ES = 1.15 vs. 0.89), with greater gains for RT4 than RT2 (p = 0.03).

CONCLUSION

RT improved muscle strength, explosive actions performance and markers of muscle size in recreationally trained men; however, four sessions of resistance training per week produced greater gains in muscular strength for the upper body measures (i.e., 1RM bench press and arm curl) when compared to two sessions per week under volume-equated conditions.

Effect of Moderate- Versus High-Intensity Interval Exercise Training on Heart Rate Variability Parameters in Inactive Latin-American Adults: A Randomized Clinical Trial

Ramírez-Vélez, R, Tordecilla-Sanders, A, Téllez-T, LA, Camelo-Prieto, D, Hernández-Quiñonez, PA, Correa-Bautista, JE, Garcia-Hermoso, A, Ramírez-Campillo, R, and Izquierdo, M. Effect of moderate- versus high-intensity interval exercise training on heart rate variability parameters in inactive Latin-American adults: a randomized clinical trial. J Strength Cond Res 34(12): 3403-3415, 2020-We investigated the effect of moderate versus high-intensity interval exercise training on the heart rate variability (HRV) indices in physically inactive adults. Twenty inactive adults were randomly allocated to receive either moderate-intensity training (MCT group) or high-intensity interval training (HIT group). The MCT group performed aerobic training at an intensity of 55-75%, which consisted of walking on a treadmill at 60-80% of the maximum heart rate (HRmax) until the expenditure of 300 kcal. The HIT group ran on a treadmill for 4 minutes at 85-95% peak HRmax and had a recovery of 4 minutes at 65% peak HRmax until the expenditure of 300 kcal. Supine resting HRV indices (time domain: SDNN = SD of normal-to-normal intervals; rMSSD = root mean square successive difference of R-R intervals and frequency domain: HFLn = high-frequency spectral power; LF = low-frequency spectral power and HF/LF ratio) were measured at baseline and 12 weeks thereafter. The SDNN changes were 3.4 (8.9) milliseconds in the MCT group and 29.1 (7.6) milliseconds in the HIT group {difference between groups 32.6 (95% confidence interval, 24.9 to 40.4 [p = 0.01])}. The LF/HFLn ratio changes were 0.19 (0.03) milliseconds in the MCT group and 0.13 (0.01) milliseconds in the HIT group (p between groups = 0.016). No significant group differences were observed for the rMSSD, HF, and LF parameters. In inactive adults, this study showed that a 12-week HIT training program could increase short-term HRV, mostly in vagally mediated indices such as SDNN and HF/LFLn ratio power. Trial registration. ClinicalTrials.gov NCT02738385 https://clinicaltrials.gov/ct2/show/NCT01796275, registered on March 23, 2016.

Plyometric jump training effects on the physical fitness of individual-sport athletes: a systematic review with meta-analysis

Background

The aim of this study is to conduct a systematic review with meta-analysis to explore the effects of plyometric jump training (PJT) on the physical fitness of individual sport athletes (ISA).

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched through PubMed, Web of Science, and SCOPUS electronic databases. We included controlled studies that incorporated a PJT intervention among ISA (with no restriction for age or sex), that included a pre-to-post intervention assessment of physical fitness (e.g., sprint; jump). From the included studies, relevant data (e.g., PJT and participants characteristics) was extracted. We assessed the methodological quality of the included studies using the PEDro scale. Using a random-effects model, meta-analyses for a given outcome was conducted. Means and standard deviations for a measure of pre-post-intervention physical fitness from the PJT and control groups were converted to Hedges' g effect size (ES). Heterogeneity was assessed using the I ² statistic. The risk of bias was explored using the extended Egger's test. The statistical significance threshold was set at p < 0.05. Moderator analyses were conducted according to the sex, age and sport background of the athletes.

Results

Twenty-six studies of moderate-high methodological quality were included (total participants, n = 667). Compared to controls, PJT improved vertical jump (ES = 0.49; p < 0.001; I = 0.0%), linear sprint (ES = 0.23; p = 0.032; I ² = 10.9%), maximal strength (ES = 0.50; p < 0.001; I² = 0.0%) and endurance performance (ES = 0.30; p = 0.028; I² = 11.1%). No significant effect was noted for sprint with change of direction (ES = 0.34; p = 0.205; I² = 70.9%). Athlete's sex, age and sport background had no modulator role on the effect of PJT on vertical jump, linear sprint, maximal strength and endurance performance. Among the included studies, none reported adverse effects related to the PJT intervention.

Conclusions

PJT induces small improvements on ISA physical fitness, including jumping, sprinting speed, strength and endurance.

The inclusion of wildcard players during small-sided games causes alterations on players’ workload

BACKGROUND: Small-sided games are a popular training method that have shown its effectiveness in improving athletic performance in football players. OBJECTIVE: To compare the acute physiological and neuromuscular responses and time-motion characteristics during small-sided games played with and without wildcard players. METHODS: Sixteen amateur male football players completed two small-sided games protocol: 4-a-side and 4-a-side with wildcard players. Time-motion characteristics during games, muscular performance parameters before and after small-sided games protocols, physiological response in terms of heart rate and muscle oximetry and rate of perceived exertion were collected. RESULTS: Both small-sided games formats induced changes in sprint performance (before-after comparison), in the rate of perceived exertion, heart rate-related variables and time-motion parameters (p< 0.05). In a comparison between small-sided games formats, lower values of oxygen saturation, heart rate, rate of perceived exertion and time-motion parameters (p< 0.05) were reported during small-sided games with wildcard players in both working and recovery periods. CONCLUSIONS: The inclusion of wildcard players during small-sided games cause a reduction in perceptual, physiological demands and time-motion parameters when compared to control condition.

Relationship between anthropometric nutritional status and functional capacity in older adults living in the community

BACKGROUND

The functional fitness of older people may be associated with their nutritional status.

AIM

To assess the association between of anthropometric measures with functional fitness in older people.

MATERIAL AND METHODS

Cross-sectional study conducted in 75 participants aged 65 to 89 years. Body mass index (BMI), waist-to-height ratio (WHtR), fat mass (FM) and skeletal muscle mass index (SMI) were calculated from anthropometric measures. The functional fitness was determined using the Senior Fitness Test battery.

RESULTS

BMI and FM indicated obesity, and WHtR indicated cardiometabolic risk in 49%, 55% and 83% of participants, respectively. SMI indicated a low muscle mass in 91% of females. Performance standards of chair stand, arm curl, 2-min step test and 8-foot up-and-go tests were met in 1%, 8%, 1% and 89% of participants, respectively. Significant negative correlations were found between 2-min step test and BMI, WHtR and FM (r = -0.26, -0.31 and -0.48 respectively). Back scratch had a negative correlation with BMI (r = -0.23) and SMI (rho = -0.28). Significant positive correlations were found between 8-foot up-and-go, WHtR (rho = 0.28) and FM (rho = 0.23), and between 2-min step test and SMI (rho = 0.28). The coefficient of determination (R2) between 2-min step test with BMI, WHtR and FM were 0.05, 0.08 and 0.22, respectively, while the R2 between back scratch and BMI was 0.04. Multiple regression models indicated that FM affected the 2-min step test independently of BMI and WHtR (adjusted R2 = 0.22), however age and sex negatively influenced these associations.

CONCLUSIONS

Functional fitness of older adults is influenced by nutritional anthropometric measures, particularly BMI, WHtR and FM for aerobic capacity, and BMI for upper limb flexibility.

Warm-up effect on handgrip strength in sedentary and overweight women

Introduction: The evaluation of handgrip strength has gain special relevance in the area of health. However, a standardized protocol of application is required to measure it, including warm-up procedures.Objective: To compare the acute effects of different warm-up strategies on maximal handgrip strength (MHS) in sedentary and overweight women.Materials and methods: Single-blind, randomized, cross-over study in which MHS was measured in 12 overweight women under the following conditions: i) no warm-up (control condition), ii) static stretching warm-up, iii) strength-based warm-up (i.e., resistance band exercise), and iv) isometric squeezing-ball warm-up for the forearm muscles. A Jamar dynamometer was used for the measurements, which were taken on four different days, at 48-hour rest intervals; three measurement were made per hand.Results: MHS mean values were 23.8 and 24.9 kg without warm-up, 20.3 and 21.4 kg after stretching warm-up, 20.9 and 22.9 kg after strength-based warm-up, and 22.0 and 23.0 kg after squeezing-ball warm-up for non-dominant and dominant hand, respectively. No significant (p>0.05; one-way ANOVA) differences were observed between protocols, nor differences in MHS in relation to nutritional status, lean mass or fat mass.Conclusion: Warm-up is not required to measure MHS in overweight sedentary women when three measurements are made.

Changes in anthropometric parameters and physical fitness in older adults after participating in a 16-week physical activity program

Introduction: Physical activity is important for achieving healthy aging. Objective: To analyze changes in anthropometric parameters and physical fitness among Chilean older adults after participating in a 16-week physical activity program and to evaluate whether there were differences in relation to their baseline nutritional status or not. Materials and methods: Pre-experimental quantitative study. The study population consisted of 176 older adults (155 women and 21 men) distributed in three groups: normal weight (n=56), overweight (n=67) and obese (n=53). The following variables were evaluated: body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHR) and physical fitness. Results: Significant decreases between pre- and post-measurements were found for WC (p<0.001), BMI (p=0.015), and WHR (p<0.001). Improvements were observed in the following tests: chair stand (p<0.001), arm curl (p<0.001), 2-min step (p<0.001), chair sit-&-reach (p=0.018) and back scratch (p=0.014). Regarding BMI, significant changes were observed between normal weight vs. overweight participants (p=0.001) and between normal weight vs. obese participants (p=0.001). Conclusion: Older adult participants that regularly attended the physical activity program were able to reduce their WC, BMI and WHR, and also improved their physical-functional performance on the chair stand, arm curl, 2-min step, chair sit-&-reach and back scratch tests. In addition, anthropometric parameters and physical fitness also improved regardless of their baseline nutritional status.  

Association of Physical Education With Improvement of Health-Related Physical Fitness Outcomes and Fundamental Motor Skills Among Youths: A Systematic Review and Meta-analysis

IMPORTANCE

Whether quality- or quantity-based physical education (PE) interventions are associated with improvement of health-related physical fitness outcomes and fundamental motor skills (FMSs) in children and adolescents is unknown.

OBJECTIVE

To examine the association of interventions aimed at optimizing PE in terms of quality (teaching strategies or fitness infusion) or quantity (lessons per week) with health-related physical fitness and FMSs in children and adolescents.

DATA SOURCES

For this systematic review and meta-analysis, studies were identified through a systematic search of Ovid MEDLINE, Embase, Cochrane Controlled Trials Registry, and SPORTDiscus databases (from inception to October 10, 2019) with the keywords physical education OR PE OR P.E. AND fitness AND motor ability OR skills. Manual examination of references in selected articles was also performed.

STUDY SELECTION

Studies that assessed the association of quality- or quantity-based PE interventions with improvement in physical fitness and/or FMSs in youths (aged 3-18 years) were included.

DATA EXTRACTION AND SYNTHESIS

Data were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Random-effects models were used to estimate the pooled effect size (Hedges g).

MAIN OUTCOMES AND MEASURES

Health-related physical fitness outcomes and FMSs.

RESULTS

Fifty-six trials composed of 48 185 youths (48% girls) were included in the meta-analysis. Quality-based PE interventions were associated with small increases in health-related physical fitness (cardiorespiratory fitness [Hedges g = 0.24; 95% CI, 0.16-0.32] and muscular strength [Hedges g = 0.19; 95% CI, 0.09-0.29]) and FMSs (Hedges g = 0.38; 95% CI, 0.27-0.49). Subgroup analyses found stronger associations for quality-based PE interventions on body mass index (Hedges g = -0.18; 95% CI, -0.26 to -0.09), body fat (Hedges g = -0.28; 95% CI, -0.37 to -0.18), cardiorespiratory fitness (Hedges g = 0.31; 95% CI, 0.23-0.39), and muscular strength (Hedges g = 0.29; 95% CI, 0.18-0.39). Quantity-based PE interventions were associated with small increases in only cardiorespiratory fitness (Hedges g = 0.42; 95% CI, 0.30-0.55), muscular strength (Hedges g = 0.20; 95% CI, 0.08-0.31), and speed agility (Hedges g = 0.29; 95% CI, 0.07-0.51).

CONCLUSIONS AND RELEVANCE

The findings suggest that quality-based PE interventions are associated with small increases in both student health-related physical fitness components and FMSs regardless of frequency or duration of PE lessons. Because PE aims to improve more than health, high levels of active learning time may need to be balanced with opportunities for instruction, feedback, and reflection.

Is Muscular Fitness Associated with Future Health Benefits in Children and Adolescents? A Systematic Review and Meta-Analysis of Longitudinal Studies

BACKGROUND

No previous systematic review has quantitatively examined the association between muscular fitness during childhood and adolescence and health parameters later in life.

OBJECTIVE

The aim was to systematically review and meta-analyze the current evidence for a prospective association between muscular fitness in childhood and adolescence and future health status.

METHODS

Two authors systematically searched MEDLINE, EMBASE and SPORTDiscus electronic databases and conducted manual searching of reference lists of selected articles. Relevant articles were identified by the following criteria: apparently healthy children and adolescents aged 3-18 years with muscular fitness assessed at baseline (e.g., handgrip, standing long jump, sit-ups, among others), and a follow-up period of ≥ 1 year. The outcome measures were anthropometric and adiposity measurements and cardiometabolic, bone and musculoskeletal health parameters. Two authors independently extracted data.

RESULTS

Thirty studies were included in the meta-analysis, yielding a total of 21,686 participants. The meta-analysis found a significant, moderate-large (p < 0.05) effect size between muscular fitness at baseline and body mass index (r = - 0.14; 95% confidence interval (CI) - 0.21 to - 0.07), skinfold thickness (r = - 0.32; 95% CI - 0.40 to - 0.23), homeostasis model assessment estimated insulin resistance (r = - 0.10; 95% CI - 0.16 to - 0.05), triglycerides (r = - 0.22; 95% CI - 0.30 to - 0.13), cardiovascular disease risk score (r = - 0.29; 95% CI - 0.39 to - 0.18), and bone mineral density (r = 0.166; 95% CI 0.086 to 0.243) at follow-up.

CONCLUSION

A prospective negative association was observed between muscular fitness in childhood/adolescence and adiposity and cardiometabolic parameters in later life, together with a positive association for bone health. There is inconclusive evidence for low back pain benefits.

Analysis of jump load during a volleyball season in terms of player role

OBJECTIVES

The aim of this study was to analyze the jump load performed by top-level volleyball players during an entire training season in terms of the player role, training period, type of daily training, and quality of opposition in the subsequent match.

DESIGN

Longitudinal panel observational study.

METHODS

The total number of jumps performed by players was recorded through 174 training days distributed in 32 weeks during the 2016/2017 season (pre-season, 5 weeks; in-season, 27 weeks). The players role were classified as middle-blocker, outside-hitter, opposite and setter (the libero was omitted). A generalized mixed linear model was performed (with Bonferroni post hoc test at p<0.05) to assess the effect of training variables and the repeated-measures data of players' jumps along various training days. Additionally, the effect sizes at 95% confidence intervals were calculated to compare the jump load between players' role and training variables.

RESULTS

The results showed a significant and moderate higher amount of jumps performed by middle-blockers regardless the type of macro- or micro-cycle, the micro-cycle phase, the type of training and the quality of match opposition. Contrarily, the setter performs the least jump load in all variables analyzed. Only the players' role, macro-cycle and micro-cycle phase had significant effects on the player's jump load variation along the season.

CONCLUSIONS

This information could be useful to guide the monitoring and preparation process for coaches and physical trainers. These values allow differentiating between players' role and could be used as references values in order to avoid injuries whereas performance increase along the season.

Acute responses to 4 vs. 4 small-sided games in football players

The aim of this study was to examine acute physiological responses, physical fitness parameters and time-motion characteristics associated with a 4-a-side small-sided game in amateur level players. Sixteen male football players (age 23.9±4.2 years) completed one 4-a-side small-sided game with the aim of maintaining ball possession as long as possible. The participants were monitored for external load and physiological parameters, and tested before and after for physical fitness assessment. A Student’s paired t-test was conducted to determine the differences in physical fitness assessment. A repeated measures analysis of variance (ANOVA), with Bonferroni post-hoc test, was used to determine the dynamics of physiological parameters in players, their RPE and time-motion characteristics of SSG. A significant difference was found in 20 m sprint time between before and after the SSG (Δ=+1.3%) . No significant differences were found between bouts or recovery periods for THb and SmO2, nor between HR-related variables (ES=.005-.383). Compared to RPE in bout 1, greater values were observed in bouts 2, 3, and 4 (Δ=+5.3%, p=.008, ES=.40; Δ=+9.6%, p=.002, ES=.98; Δ=+15.1%, p=.000, ES=1.29; respectively). No significant differences were found between bouts for time-motion characteristics. The results demonstrated that RPE responses increased throughout bout periods, whereas the rest of physiological parameters were maintained over the entire protocol. Due to possible fatigue accumulation, physical fitness performance was impaired (sprint) and the external load was reduced over the course of the protocol.

How Do Spatiotemporal Parameters and Lower-Body Stiffness Change with Increased Running Velocity? A Comparison Between Novice and Elite Level Runners

This study aimed to examine the effect of running velocity on spatiotemporal parameters and lower-body stiffness of endurance runners, and the influence of the performance level on those adaptations. Twenty-two male runners (novice [NR], n = 12, and elite runners [ER], n = 10) performed an incremental running test with a total of 5 different running velocities (10, 12, 14, 16, 18 km/h). Each condition lasted 1 min (30 s acclimatization period, and 30 s recording period). Spatiotemporal parameters were measured using the OptoGait system. Vertical (Kvert) and leg (Kleg) stiffness were calculated according to the sine-wave method. A repeated measures ANOVA (2 x 5, group x velocities) revealed significant adaptations (p < 0.05) to increased velocity in all spatiotemporal parameters and Kvert in both NR and ER. ER showed a greater flight time (FT) and step angle (at 18 km/h) (p < 0.05), longer step length (SL) and lower step frequency (SF) (p < 0.05), whereas no between-group differences were found in contact time (CT) nor in the sub-phases during CT at any speed (p ≥ 0.05). ER also showed lower Kvert values at every running velocity (p < 0.05), and no differences in Kleg (p ≥ 0.05). In conclusion, lower SF and Kvert and, thereby, longer FT and SL, seem to be the main spatiotemporal characteristics of high-level runners compared to their low-level counterparts.

Agreement between the spatiotemporal gait parameters from two different wearable devices and high-speed video analysis

This study aimed to evaluate the concurrent validity of two different inertial measurement units for measuring spatiotemporal parameters during running on a treadmill, by comparing data with a high-speed video analysis (VA) at 1,000 Hz. Forty-nine endurance runners performed a running protocol on a treadmill at comfortable velocity (i.e., 3.25 ± 0.36 m.s^-1). Those wearable devices (i.e., Stryd™ and RunScribe™ systems) were compared to a high-speed VA, as a reference system for measuring spatiotemporal parameters (i.e. contact time [CT], flight time [FT], step frequency [SF] and step length [SL]) during running at comfortable velocity. The pairwise comparison revealed that the Stryd™ system underestimated CT (5.2%, p < 0.001) and overestimated FT (15.1%, p < 0.001) compared to the VA; whereas the RunScribe™ system underestimated CT (2.3%, p = 0.009). No significant differences were observed in SF and SL between the wearable devices and VA. The intra class correlation coefficient (ICC) revealed an almost perfect association between both systems and high-speed VA (ICC > 0.81). The Bland-Altman plots revealed heteroscedasticity of error (r² = 0.166) for the CT from the Stryd™ system, whereas no heteroscedasticity of error (r² < 0.1) was revealed in the rest of parameters. In conclusion, the results obtained suggest that both foot pods are valid tools for measuring spatiotemporal parameters during running on a treadmill at comfortable velocity. If the limits of agreement of both systems are considered in respect to high-speed VA, the RunScribe™ seems to be a more accurate system for measuring temporal parameters and SL than the Stryd™ system.

[Lifestyles of Chilean housewives. Analysis of the 2009-2010 Chilean Health Survey]

BACKGROUND

Housewives represent a important proportion of the Chilean population. However, there is limited evidence about their lifestyles.

AIM

To characterize lifestyles and determine the level of compliance with healthy lifestyles guidelines of housewives in Chile.

MATERIAL AND METHODS

Housewives from the 2009-2010 National Health Survey were included. The variables studied included levels of physical activity (PA), sedentary behavior, diet, hours of sleep and smoking. Compliance with healthy lifestyle behaviors was evaluated through logistic regression, granting a value of 1 for compliance and 0 for non-compliance. A healthy lifestyle was defined as meeting at least four healthy behaviors.

RESULTS

Housewives aged > 55 years had a higher BMI and waist circumference compared to those aged < 40 years. Housewives were also more likely to report moderate alcohol consumption and were more likely to meet a healthier lifestyle score (Odds ratio = 1.52 [95% confidence intervals: 1.09 to 2.11], p = 0.013). No significant age trends were observed for other lifestyle behaviors.

CONCLUSIONS

Housewives had high levels of central obesity, excess body weight and high levels of salt intake but low alcohol intake. Their healthy lifestyles behaviors increased along with increasing age.

Low sleep time is associated with higher levels of blood pressure and fat mass in Amerindian schoolchildren

OBJECTIVES

While altered sleep patterns (ie, low sleep time) have been studied and reported in adults as a new cardiometabolic risk factor, less information is available on how sleep patterns impact children of different ethnicities. The aim of this study was to compare the levels of blood pressure and other cardiometabolic risk factors in relation to different levels of sleep time in schoolchildren of Amerindian Mapuche or European-ancestry of Southern Chile.

METHODS

In a cross-sectional study, 540 Chilean schoolchildren (6-13 years) were divided into two ethnic groups (n = 119 Mapuche Amerindians and n = 421 European-ancestry). Groups were analyzed according to sleep time per day as registered by parents' report and distributed into quartile categories of sleep time: Mapuche (quartile 1 [Q1] ≥10.0 h, n = 34; Q2 9.5-10.0 h, n = 29; Q3 8.5-9.0 h, n = 31; and Q4 ≤ 8.5 h, n = 25), and European (Q1, n = 99; Q2, n = 77; Q3, n = 144; Q4, n = 101). The main cardiovascular parameters (systolic [SBP] and diastolic blood pressure) were complemented with anthropometric/body composition (body mass, body mass index [BMI], waist circumference, fat mass, muscle mass, lean mass), cardiorespiratory (heart rate rest, oxygen saturation), and muscle strength (handgrip of dominant and non-dominant arm) outcomes.

RESULTS

From Q1 and across Q2, Q3, and Q4, there was an increase in delta mean SBP in both Mapuche (Δ +17.6 mm Hg) and European (Δ +7.3 mm Hg) schoolchildren with 30-90 min of decreased sleep time (using ≥10 h as reference in Q1). The tendency for worsening of other cardiometabolic risk factors was maintained for delta mean BMI (Δ +2.6 kg/m² ), waist circumference (Δ +12 cm), and fat mass (Δ +8.3%) in Mapuches, whereas European peers showed only worsened waist circumference (Δ +6 cm) across Q2, Q3, and Q4 in comparison with reference Q1. There was also a higher prevalence of hypertension in Mapuche (31.1%) compared to in European schoolchildren (17.6%).

CONCLUSIONS

Mapuche and European schoolchildren show higher levels of SBP with a decrease in sleep time of 30 min; however, there is a higher prevalence of hypertension and obesity in ethnic Mapuches than in European schoolchildren. These findings indicate that more studies should be applied at early school ages for preventing low sleep time and their related cardiometabolic risk factors for hypertension development in different ethnic groups.

Influence of adiposity and fatigue on the scapular muscle recruitment order

Background

Several authors have indicated that excess body weight can modify the electromyographic (EMG) amplitude due to the accumulation of subcutaneous fat. This accumulation of adipose tissue around the muscle would affect the metabolic capacity during functional activities. On the other hand, some authors have not observed differences in the myoelectric manifestations of fatigue between normal weight and obese people. Furthermore, these manifestations have not been investigated regarding EMG onset latency, which indicates a pattern of muscle activation between different muscles. The objective of this study was to determine whether an increase in body weight, skinfolds, and muscle fatigue modify the trapezius and serratus anterior (SA) onset latencies and to determine the scapular muscle recruitment order in fatigue and excess body weight conditions.

Methods

This cross-sectional study was carried out in a university laboratory. The participants were randomly assigned to the no-fatigue group (17 participants) or the fatigue (17 participants) group. The body mass index, skinfold thickness (axillary, pectoral, and subscapular), and percentage of body fat were measured. In addition, the onset latency of the scapular muscles [lower trapezius (LT), middle trapezius (MT), upper trapezius (UT), and SA] was assessed by surface EMG during the performance of a voluntary arm raise task. A multiple linear regression model was adjusted and analyzed for the additive combination of the variables, percentage body fat, skinfold thickness, and fatigue. The differences in onset latency between the scapular muscles were analyzed using a three-way repeated measure analysis of variance. In all the tests, an alpha level <0.05 was considered statistically significant.

Results

For the MT, LT, and SA onset latencies, the body mass index was associated with a delayed onset latency when it was adjusted for the additive combination of percentage of body fat, skinfold thickness, and fatigue. Of these adjustment factors, the subscapular skinfold thickness (R ² = 0.51; β = 10.7; p = 0.001) and fatigue (R ² = 0.86; β = 95.4; p = 0.001) primarily contributed to the increase in SA onset latency. A significant muscle ×body mass index ×fatigue interaction (F = 4.182; p = 0.008) was observed. In the fatigue/excess body weight condition, the UT was activated significantly earlier than the other three scapular muscles (p < 0.001) and SA activation was significantly delayed compared to LT (p < 0.001).

Discussion

Excess body weight, adjusted for skinfold thickness (axillary and subscapular) and fatigue, increases the onset latency of the MT, LT, and SA muscles and modifies the recruitment order of scapular muscles. In fact, the scapular stabilizing muscles (MT, LT, and SA) increase their onset latency in comparison to the UT muscle. These results were not observed when excess body weight was considered as an individual variable or when adjusted by the percentage body fat.

Is Muscular Fitness Associated with Future Health Benefits in Children and Adolescents? A Systematic Review and Meta-Analysis of Longitudinal Studies

BACKGROUND

No previous systematic review has quantitatively examined the association between muscular fitness during childhood and adolescence and health parameters later in life.

OBJECTIVE

The aim was to systematically review and meta-analyze the current evidence for a prospective association between muscular fitness in childhood and adolescence and future health status.

METHODS

Two authors systematically searched MEDLINE, EMBASE and SPORTDiscus electronic databases and conducted manual searching of reference lists of selected articles. Relevant articles were identified by the following criteria: apparently healthy children and adolescents aged 3-18 years with muscular fitness assessed at baseline (e.g., handgrip, standing long jump, sit-ups, among others), and a follow-up period of ≥ 1 year. The outcome measures were anthropometric and adiposity measurements and cardiometabolic, bone and musculoskeletal health parameters. Two authors independently extracted data.

RESULTS

Thirty studies were included in the meta-analysis, yielding a total of 21,686 participants. The meta-analysis found a significant, moderate-large (p < 0.05) effect size between muscular fitness at baseline and body mass index (r = - 0.14; 95% confidence interval (CI) - 0.21 to - 0.07), skinfold thickness (r = - 0.32; 95% CI - 0.40 to - 0.23), homeostasis model assessment estimated insulin resistance (r = - 0.10; 95% CI - 0.16 to - 0.05), triglycerides (r = - 0.22; 95% CI - 0.30 to - 0.13), cardiovascular disease risk score (r = - 0.29; 95% CI - 0.39 to - 0.18), and bone mineral density (r = 0.166; 95% CI 0.086 to 0.243) at follow-up.

CONCLUSION

A prospective negative association was observed between muscular fitness in childhood/adolescence and adiposity and cardiometabolic parameters in later life, together with a positive association for bone health. There is inconclusive evidence for low back pain benefits.

Association of physical inactivity with blood pressure and cardiovascular risk factors in Amerindian schoolchildren

OBJECTIVES

There is a wealth of published data on blood pressure (BP) and physical activity in adults of European descent, but less information is available for Amerindian schoolchildren. The aim of this study was to investigate whether BP and other cardiometabolic risk factors differ by physical activity levels in schoolchildren from different ethnic backgrounds.

METHODS

This was a cross-sectional study of 540 schoolchildren (6-13 years) from two ethnic backgrounds (n = 119 Mapuche Amerindians and n = 421 of European descent). Physical activity was measured using international physical activity recommendations and a standard questionnaire, and ethnicity was classified according to previous methods using surnames. The population was divided into the following four groups: (a) physically active Mapuches (n = 45) and of European descent (n = 101); and (b) physically inactive Mapuches (n = 74) and of European descent (n = 320).

RESULTS

In physically inactive schoolchildren, significant differences were found between schoolchildren of Mapuche and European descent in systolic (134 ± 3 mmHg vs 130 ± 5 mmHg, respectively, P = .034) and diastolic BP (85 ± 13 mmHg vs 81 ± 3 mmHg, P = .029). For other cardiometabolic risk factors, schoolchildren with Mapuche surnames were significantly less likely to be classified with normal weight (5 [6.8%] vs 85 [26.6%]), and more likely to be obese (30 [40.5%] vs 76 [26.6%]) at P < .0001 than European peers. Additionally, significant differences were found between Mapuche schoolchildren vs European peers in the outcomes body mass (51.2 ± 18 kg vs 47.0 ± 15), z score of body mass index (2.16 vs 1.70), fat-to-muscle mass ratio (1.68 vs 0.96), resting heart rate (81.7 ± 10 vs 86.8 ± 16), waist circumference (89.3 ± 5 cm vs 76.3 ± 2 cm), muscle mass (18.2 ± 3 kg vs 16.2 ± 2 kg), and handgrip strength normalized by body mass (0.68 vs 0.57 kg).

CONCLUSION

Under conditions of similar physical inactivity, Mapuche schoolchildren have a more adverse cardiovascular and adiposity profile than their counterparts of European descent.

Concurrent exercise training on hyperglycemia and comorbidities associated: Non-responders using clinical cutoff points

This study examined the effects of a 20-week concurrent training (CT, ie, resistance plus endurance training) intervention on cardiovascular risk factors, such as body composition, blood pressure, and lipid profile among adult women with hyperglycemia. A secondary aim was to report prevalence of non-responders for the different study outcomes. Physically inactive overweight/obese and hyperglycemic adult women (42 ± 6 years; BMI = 30.9 ± 4.8 kg/m² ) were randomly assigned to a 20-week CT intervention group or a control (non-exercise) group (CG) (n = 14/group). Cardiovascular risk factors for body composition (body mass, waist circumference [WC], fat mass, and lean mass), blood pressure, and lipid profile (total, LDL cholesterol and HDL cholesterol, triglycerides, and fasting glucose) were assessed before and after the 20-week intervention. Our results show that a CT intervention results in a reduction of comorbidities in terms of abdominal obesity and cardiovascular risk in adult women with hyperglycemia by decreasing WC and improving lipid profile in "mean" terms. At the individual level, after CT, some subjects changed their status from a "high" to a "low" cardiovascular risk in terms of WC, while others changed from hypertension to either high blood pressure or normotension, or from high blood pressure to normotension, and others changed from hypercholesterolemia/dyslipidemia to normocholesterolemia. Overall, there were ~30%, 50%, and 20% of individuals in the CT exercise group who showed no change/adverse response for body composition, blood pressure, and lipid profile, respectively, after the 20-week CT intervention.

Improvements cardiometabolic risk factors in Latin American Amerindians (the Mapuche) with concurrent training

Our aim was to investigate the effects of 12 weeks of CT (ie, high-intensity interval and resistance training) in Mapuche adults from Chile and in their peers of European descent. In total, 96 hyperglycemic adult women (mean age 46 years [95% confidence interval; 38, 53]) were divided in four groups: Mapuche CT (Map-CT, n = 14) or control group (Map-CG, n = 44), and European CT (Eur-CT, n = 14) or control group (Eur-CG, n = 23). The following endpoints were analyzed at baseline and after 12 weeks: anthropometric (body mass, body mass index, waist circumference), body composition (fat mass, muscle mass, lean mass), cardiovascular (systolic [SBP]/diastolic [DBP] blood pressure), metabolic (blood fasting glucose and total cholesterol), and muscle strength (handgrip of dominant/non-dominant arm). There were significant positive changes in body mass, body fat, and muscle mass (P < 0.0001) in both Map-CT and Eur-CT groups, whereas waist circumference was decreased significantly only in the Eur-CT group (P < 0.0001). Both Map-CT and Eur-CT groups showed decreased levels of fasting glucose (P < 0.05) and total cholesterol after the intervention (P < 0.0001). Also, both Map-CT (P < 0.05) and Eur-CT (P = 0.01) groups showed a lowered SBP. Finally, significant increases were observed after training in handgrip strength (dominant arm) in Map-CT and Eur-CT groups (both P < 0.0001). CT led to similar improvements in cardiometabolic risk factors for metabolic syndrome development in Mapuche and European participants, with additional improvements in other anthropometric, body composition, cardiovascular, metabolic, and muscle strength parameters related to the prevention of metabolic syndrome. These results suggest future more complex studies.

Association of maximal voluntary isometric handgrip strength with age, gender and handedness in older people

BACKGROUND

Maximal voluntary isometric handgrip strength (MVIHS) is influenced by age, sex, and handedness.

AIM

To assess the association of MVIHS with age, sex, and handedness in older adults.

MATERIAL AND METHODS

MVIHS was measured using a digital dynamometer in 60 men and 60 women aged 73 ± 6 years. Weight, height and handedness were also recorded. For analysis purposes, participants were divided into two age groups (65 to 70.9 years of age and ≥ 71 years).

RESULTS

A negative correlation was observed between age and MVIHS in the non-dominant (r = -0.65 and -0.59 in men and women, respectively) and dominant hands (r = -0.71 and -0.64 in men and women, respectively). When age and MVIHS were correlated in the group aged 65-70 years, a significant correlation was observed in the non-dominant (r = -045 and -0.61 in men and women, respectively) and dominant hands (r = -0.47 and -0.64 in men and women, respectively). In the group aged ≥ 71 years, a stronger correlation with age was also observed in the non-dominant (r = -0.92 and -0.90 in men and women, respectively) and dominant hands (r = -0.95 and -0.90 in men and women, respectively). MVIHS was 2.8 to 8.9% lower in the non-dominant than in the dominant hand in all age groups. MVIHS was lower in women than in men in both age groups.

CONCLUSIONS

MVIHS declines with age (especially after 71 years of age), is higher in men than women, and higher in the dominant than the non-dominant hand.

Effectiveness of HIIT compared to moderate continuous training in improving vascular parameters in inactive adults

Background

Strong evidence shows that physical inactivity increases the risk of many adverse health conditions, including major non-communicable diseases, such as cardiovascular disease (CVD), metabolic syndrome, and breast and colon cancers, and shortens life expectancy. We aimed to determine the effects of moderate (MCT)- versus high-intensity interval training (HIT) on vascular function parameters in physically inactive adults. We hypothesized that individualized HIT prescription would improve the vascular function parameters more than the MCT in a greater proportion of individuals.

Methods

Twenty-one inactive adults were randomly allocated to receive either MCT group (60–75% of their heart rate reserve, [HRR] or HIT group (4 min at 85–95% of peak HRR), 3 days a week for 12 weeks. Vascular function (brachial artery flow-mediated dilation, FMD [%], normalized brachial artery flow-mediated dilation, FMDn [%], aortic pulse wave velocity, PWV [m·s^− 1], AIx, augmentation index: aortic and brachial [%]), were measured at baseline and over 12 weeks of training. In order for a participant to be considered a responder to improvements in vascular function parameters (FMDn and PWV), the typical error was calculated in a favorable direction.

Results

FMD changed by − 1.0% (SE 2.1, d = 0.388) in the MCT group, and + 1.8% (SE 1.8, d = 0.699) in the HIT group (no significant difference between groups: 2.9% [95% CI, − 3.0 to 8.8]. PWV changed by + 0.1 m·s^− 1 (SE 0.2, d = 0.087) in the MCT group but decreased by − 0.4 m·s^− 1 in the HIT group (SE 0.2, d = 0.497), with significant difference between groups: − 0.4 [95% CI, − 0.2 to − 0.7]. There was not a significant difference in the prevalence of no-responder for FMD (%) between the MCT and HIT groups (66% versus 36%, P = 0.157). Regarding PWV (m·s^− 1), an analysis showed that the prevalence of no-responder was 77% (7 cases) in the MCT group and 45% (5 cases) in the HIT group (P = 0.114).

Conclusions

Under the conditions of the present study, both groups experienced changed in vascular function parameters. Compared to MCT group, HIT is more efficacious for improving FMD and decreasing PWV, in physically inactive adults.

Trial registration

ClinicalTrials.gov NCT02738385 registered on 23 March 2016.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-0981-z) contains supplementary material, which is available to authorized users.

How does the slope gradient affect spatiotemporal parameters during running? Influence of athletic level and vertical and leg stiffness

BACKGROUND

The current evidence leaves certain questions unanswered, including whether well-trained athletes adapt to different slope gradients in the same way as amateurs, and whether stiffness influences spatiotemporal adaptations during uphill running.

RESEARCH QUESTION

This study aimed to determine the effect of different slope gradients (0%-11%) on spatiotemporal gait characteristics during running, taking into account the influence of athletic level, vertical and leg stiffness.

METHODS

Male endurance runners (12 amateurs, 10 highly-trained) performed a running test on a motorized treadmill. The running velocity was set at 12 km/h, and participants completed six different running conditions (0, 3, 5, 7, 9 and 11% gradients). Spatiotemporal parameters were measured using the OptoGait system. Vertical (Kvert) and leg (Kleg) stiffness were calculated according to the sine-wave method.

RESULTS

A 2 (amateur; highly-trained) × 6 (running conditions) ANOVA found no significant between-group differences in spatiotemporal parameters at any gradient (P ≥ 0.05); however, significant Kvert and Kleg differences (P < 0.05) were found within both groups with increasing gradients. Stepwise linear regression analysis showed that Kleg was strongly associated with contact time (R²  = 0.797, P < 0.001), whereas Kvert was associated with spatiotemporal adaptations to different slope gradients (R²  = 0.547, P = 0.002).

SIGNIFICANCE

An increased slope gradient (0-11%) at a given running velocity (12 km.h^-1) caused spatiotemporal adaptations (i.e., increased CT and SF and decreased FT, SL and SA) regardless of the athletic level of the runner, although a non-significant trend differentiated the adaptations between the amateur and highly-trained groups. The results also indicated that leg stiffness plays a key role in the characteristics of spatiotemporal gait during level running, whereas vertical stiffness is strongly associated with spatiotemporal adaptations when running uphill.

[An equation to predict maximum oxygen consumption from the six-minute walk test in healthy young adults]

BACKGROUND

The six-minute walk test (SMWT) is an easy-to-use test that measures walking distance.

AIM

To elaborate an equation to estimate the maximum oxygen consumption (VO2 max) using the results of the SMWT.

MATERIAL AND METHODS

Forty men and 40 women aged 22.5 ± 2 years, underwent a SMWT to measure the total walked distance and the recovery heart rate (RhR) Also, VO2 max was estimated from the maximal workload achieved in a cyclo-ergometer using the Storer test. A multivariate regression analysis resulted in a prediction equation that was validated with distributional assumptions of normality, independence and homoscedasticity. The limits of concordance of the predictive model were checked with the Bland-Altman diagram.

RESULTS

Body mass index (BMI), sex, RhR and total walked distance explained VO2 max variance by 3.4, 73.1, 17.9 and 32.8%, respectively. The prediction equation achieved was VO2 max (ml.min-1) = -3672.585 + (966.472 × Sex [1: female, 2: male]) + (-18.492 X RhR [beats.minute-1]) + (9.191 X Distance [m]) + (87.707 × BMI). The R2 of the equation was 0.91 (p < 0.01).

CONCLUSIONS

This equation predicts VO2 max in Chilean university students according to sex, BMI, cardiovascular response and performance in the SMWT.

[Risk of cognitive impairment among older people with diabetes or family history of the disease]

BACKGROUND

Although cardiovascular risk factors are associated with an impaired cognitive function, the impact of diabetes on cognitive function in Chilean adults is unknown.

AIM

To investigate the association of diabetes or family history of the disease with cognitive impairment in older adults.

MATERIALS AND METHODS

Data from the 2009-2010 Chilean National Health Survey including 1,384 participants aged ≥ 60 years were included in this study. A score below 13 points for the Mini Mental State Examination (MMSE) was considered an indication of cognitive impairment. Logistic regression analyses were performed to assess the association between MMSE, diabetes and family history of the disease.

RESULTS

Cognitive impairment increased with age (Odds ratio (OR): 1.83 [95% confidence intervals (CI): 1.53; 2.19], p < 0.01, per 5 years increment in age). This trend was greater in individuals with diabetes (OR: 2.37 [95% CI: 1.68; 3.35], p < 0.01) compared to those without the disease. A similar trend was identified among individuals with a family history of diabetes compared to those without.

CONCLUSIONS

Older adults with diabetes are more susceptible to develop cognitive impairment.

Exercise and glucose control in children with insulin resistance: prevalence of non-responders

BACKGROUND

Exercise training improves cardiometabolic outcomes in 'mean terms', but little information is available in children about the impact of the frequency/week and the wide inter-individual variability to exercise training reported in adults.

OBJECTIVES

We compared the effects of resistance training (RT) and high-intensity interval training (HIT), and 'high' and 'low' frequency of training/week, for their effectiveness in decreasing insulin resistance (IR) levels in schoolchildren. A second aim was to decscribe and compare the prevalence of non-responders (NRs) between the different frequencies of training protocol.

METHODS

Fifty-three schoolchildren with IR were randomly assigned into four groups: RT at high frequency (three times/week), HIT at high frequency, RT at a low frequency (two times/week) and HIT at low frequency. The intervention lasted 6 weeks. Blood samples and body composition, blood pressure and performance measurements were taken before and after the intervention.

RESULTS

The prevalence of NRs was similar between the RTHF and HITHF (25.0% vs. 25.0%, P > 0.05) and RTLF and HITLF groups (20.0% vs. 46.6%, P = 0.174) for decreasing homeostasis model assessment of IR. However, significant differences in the prevalence of NRs were detected between RTHF and HITHF groups in fasting glucose (FGL) (18.7% vs. 58.3%, P < 0.031).

CONCLUSIONS

Both RT and HIT improves the glucose control parameters in schoolchildren over 6 weeks, but only HIT is independent of a high or low frequency of training/week. The prevalence of NRs is similar for decreasing homeostasis model assessment of IR comparing each exercise mode in high vs. low frequency/week. However, both high- and low-frequency RT and HIT results in differences in the prevalence of NRs for FGL and other cardiometabolic and performance outcomes.

Prevalence of Non-responders for Blood Pressure and Cardiometabolic Risk Factors Among Prehypertensive Women After Long-Term High-Intensity Interval Training

Background: Exercise is known to improve cardiometabolic outcomes; however, results are typically reported as mean values, and there is wide interindividual variability in terms of response that has not been explored in populations at risk for hypertension. Our aim was to investigate both the effects on and the prevalence of non-responders (NRs) for decreasing blood pressure (BP) and other risk factors among prehypertensive women after long-term high-intensity interval training (HIIT). A secondary aim was to report potential variables that can predict decreases in BP after HIIT. Methods: Sedentary overweight/obese women (age 35.9 ± 5.4 year; body mass index [BMI] 30.9 ± 6.2 kg/m2) were assigned to a prehypertensive (PreHTN; N = 44) or normotensive (NT; N = 40) group according to their ambulatory BP at baseline. Subjects underwent a thrice-weekly 16-week HIIT program (7-10 × 1 min exercise with 2 min of rest). Training-induced changes in body composition and cardiovascular, metabolic, strength, and endurance performance markers were measured, and the prevalence of NRs was reported as a percentage. All outcomes were analyzed by multivariable regression. Results: Statistically significant (P < 0.05) decreases in systolic BP (SBP) were detected in the PreHTN group (Δ -8 mmHg) compared with baseline, whereas the NT group (Δ + 3 mmHg) showed a non-significant increase in SBP. Diastolic BP (DBP) was significantly decreased in the PreHTN group (Δ -5.8 mmHg) and non-significantly decreased (Δ -2 mmHg) in the NT group. Also, there were significant differences (P < 0.0001) in the prevalence of NRs based on SBP between the PreHTN and NT groups (11.4 vs. 68.8%), but similar prevalence of NRs based on DBP. SBP alone was a powerful predictive factor for a beneficial SBP reduction, explaining 51.2% of the results, which was similar to other more complex models tested. Conclusion: The prevalence of NRs based on SBP and DBP was different between prehypertensive and normotensive subjects after 16 weeks of HIIT. Other comorbidities such as body composition and metabolic outcomes showed almost similar modifications between prehypertensive and normotensive subjects, being the most basic predictive factor for BP reduction baseline SBP, which we refer to as 'BP health status' (51.2%). This improvement in BP was accompanied by other known improvements of HIIT on body composition, metabolic and endurance performance in both study cohorts. Trial Registration: ClinicalTrials.gov ID: NCT03000140 (Register 20 December, 2016).

Effects of Plyometric Training on Explosive and Endurance Performance at Sea Level and at High Altitude

Plyometric training performed at sea level enhance explosive and endurance performance at sea level. However, its effects on explosive and endurance performance at high altitude had not been studied. Therefore, the aim of this study was to determine the effects of a sea level short-term (i.e., 4-week) plyometric training program on explosive and endurance performance at sea level and at high altitude (i.e., 3,270 m above sea level). Participants were randomly assigned to a control group (n = 12) and a plyometric training group (n = 11). Neuromuscular (reactive strength index – RSI) and endurance (2-km time-trial; running economy [RE]; maximal oxygen uptake - VO₂max) measurements were performed at sea level before, at sea level after intervention (SL +4 week), and at high altitude 24-h post SL +4 week. The ANOVA revealed that at SL +4 week the VO₂max was not significantly changed in any group, although RE, RSI and 2-km time trial were significantly (p < 0.05) improved in the plyometric training group. After training, when both groups were exposed to high altitude, participants from the plyometric training group showed a greater RSI (p < 0.05) and were able to maintain their 2-km time trial (11.3 ± 0.5 min vs. 10.7 ± 0.6 min) compared to their pre-training sea level performance. In contrast, the control group showed no improvement in RSI, with a worse 2-km time trial performance (10.3 ± 0.8 min vs. 9.02 ± 0.64 min; p < 0.05; ES = 0.13). Moreover, after training, both at sea level and at high altitude the plyometric training group demonstrated a greater (p < 0.05) RSI and 2-km time trial performance compared to the control group. The oxygen saturation was significantly decreased after acute exposure to high altitude in the two groups (p < 0.05). These results confirm the beneficial effects of sea level short-term plyometric training on explosive and endurance performance at sea level. Moreover, current results indicates that plyometric training may also be of value for endurance athletes performing after an acute exposure to high altitude.

Minimum time required for assessing step variability during running at submaximal velocities

This study aimed to determine the minimum time required for assessing spatiotemporal variability during continuous running at different submaximal velocities and, thereby, the number of steps required. Nineteen trained endurance runners performed an incremental running protocol, with a 3-min recording period at 10, 12, 14 and 16 km/h. Spatiotemporal parameters (contact and flight times, step length and step frequency) were measured using the OptoGait system and step variability was considered for each parameter, in terms of within-participants standard deviation (SD) and coefficient of variation (CV%). Step variability was considered over six different durations at every velocity tested: 0-10 s, 0-20 s, 0-30 s, 0-60 s, 0-120 s and 0-180 s. The repeated measures ANOVA revealed no significant differences in the magnitude of the four spatiotemporal parameters between the recording intervals at each running velocity tested (p ≥ 0.05, ICC > 0.90). The post-hoc analysis confirmed no significant differences in step variability (SD and CV% of each spatiotemporal parameter at any velocity tested) between measurements. The Bland-Altman limits of agreement method showed that longer recording intervals yield smaller systematic bias, random errors, and narrower limits of agreement, regardless of running velocity. The results suggest that the duration of the recording period required to estimate spatiotemporal variability plays an important role in the accuracy of the measurement, regardless of running velocity (10-16 km/h).

[Effects of a six weeks exercise training program for type 2 diabetes mellitus and hypertensive patients]

BACKGROUND

There is a wide interindividual variability in the response to a period of exercise training. The science have reported that a minimum of participants could be non-responders for improving different health-related outcomes after training.

AIM

To compare the effects of a 6-weeks exercise program on body composition, cardiovascular and metabolic outcomes patients with type 2 diabetes and hypertension.

MATERIAL AND METHODS

Data from 23 trained subjects were used in a secondary analysis of the response to exercise. Of these, 14 were considered adherent to training and nine as non-adherent. Body mass, height, waist circumference, four skinfolds and their sum, blood pressure and plasma triglyceride levels were assessed before and after the training period.

RESULTS

Among adherent participants, significant reductions were observed in the sum of four skinfolds (30 ± 7 to 27 ± 6 mm, p ≤ 0.05), systolic blood pressure (133 ± 18 to 127 ± 20 mmHg; p ≤ 0.05) and plasma triglycerides (125 ± 58 to 102 ± 34 mg/dL; p ≤ 0.05). No changes were observed in weight or diastolic blood pressure. Among non-adherent participants, no changes of measured parameters were observed. Among adherent participants, 57% were considered as non-responders for waist circumference, 7% for the sum of skinfold thickness, 50% for systolic blood pressure, 64% for diastolic blood pressure and 57% for plasma triglycerides.

CONCLUSIONS

Participants with a good adherence to a 6-weeks exercise training program experienced overall improvement in body composition, blood pressure and plasma triglycerides. The prevalence of non-responders varied considerably among measured outcomes.

Validity of the RSA-RANDOM Test for Young Soccer Players

The present study aimed to examine the reliability, usefulness, responsiveness, age-related differences and construct validity of a novel decision-making RSA test (RSA-RANDOM test) in young soccer players. Twenty-five young male soccer players performed the RSA-RANDOM test on 2 occasions separated by 5–7 days to assess test-retest reliability and determine a priori usefulness. Furthermore, the same players executed the RSA-RANDOM test 4 times throughout the season to analyse responsiveness. Forty-five players (U–13 to U–17) were evaluated in such test to examine age-related differences. Finally, 9 players were used to determine the construct validity of the test. Reliability scores showed a high intraclass correlation coefficient (ICC=0.88 to 0.90) and low coefficient of variation (CV=1.0–1.2%). The responsiveness of the RSA-RANDOM test was good, as the typical short- (1.2–1.9%), mid- (1.4–2.4%) and long-term (2.3–3.2%) changes in RSA-RANDOM performance were higher than the CV. Age-related differences analysis showed better RSA-RANDOM performance as age increased in young soccer players. Low (r=−0.50) to moderate (r=−0.75) relationships were found between the RSA-RANDOM test variables (RSA best and mean times) with high-intensity and total distance covered, respectively. A novel decision-making RSA test (RSA-RANDOM) has shown to be reliable and valid in young soccer players.

Maturation-Related Differences in Adaptations to Resistance Training in Young Male Swimmers

Moran, J, Sandercock, GRH, Ramírez-Campillo, R, Wooller, J-J, Logothetis, S, Schoenmakers, PPJM, and Parry, DA. Maturation-related differences in adaptations to resistance training in young male swimmers. J Strength Cond Res 32(1): 139-149, 2018-This study examined the effects of resistance training on muscular strength and jump performances in young male swimmers. It was hypothesized that adaptations would be of a lower magnitude in less mature (prepeak height velocity [PHV]) than in more mature (post-PHV) subjects. Fourteen pre-PHV (-1.8 ± 1.0 years) and 8 post-PHV (1.6 ± 0.5 years) swimmers undertook a 30 minutes, twice-weekly resistance training program for 8 weeks. They were compared with matched control groups (pre-PHV: -2.0 ± 1.1, n = 15; post-PHV: 1.2 ± 1.0, n = 7). The effects on lower-body isometric strength (LBS), measured with midthigh pull, and vertical jump (VJ) height in the post-PHV group were large (effect size: 1.3 [0.4 to 2.2]) and small (0.4 [-0.4 to 1.2]), respectively. Effects on LBS and VJ height in the pre-PHV group were moderate (0.8 [0.1 to 1.4]) and trivial (0.2 [-0.5 to 0.8]), respectively. Estimates in the post-PHV control group (LBS: 0.7 [-0.2 to 1.6]; VJ: 0.2 [-0.7 to 1.0]) and the pre-PHV control group (LBS: 0.1 [-0.5 to 0.7]; VJ: -0.3 [-0.9 to 0.3]) may indicate the extent to which maturation could contribute to the performance changes seen in the respective training groups. Lower-body isometric strength and VJ are trainable, but to different magnitudes, in pre- and post-PHV swimmers. After appropriate foundational training to establish technical competency, twice-weekly resistance training sessions of 30 minutes duration, comprising 3 sets of 4 exercises can be effective in pre- and post-PHV youth.

[Oxygen peak consumption is a better predictor of cardiovascular risk than handgrip strength in older Chilean women]

BACKGROUND

Handgrip strength (HS) and peak oxygen consumption (Vo2peak) are powerful predictors of cardiovascular risk, although it is unknown which of the two variables is the better predictor.

AIM

The objective of the following study was to relate HS and Vo2peak to cardiovascular risk markers in older Chilean women.

METHODS

Physically active adult women (n=51; age, 69±4.7years) participated in this study. The HS and Vo2peak were evaluated and related to the anthropometric variables of body mass, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist ratio (WR), and waist height ratio (WHR), as well as with the cardiovascular variables systolic (SBP) and diastolic (DBP) and cardiac recovery in one minute (RHR1). A multilinear regression model was used for the analysis of the associated variables (P<.05).

RESULTS

The cardiovascular risk markers associated (P<.05) with the handgrip strength of the dominant limb (HS_DL) were body mass, BMI, WR, and WHR. The handgrip strength of the non-dominant limb (HS_NDL) was associated with body mass. Vo2peak was associated with body mass, BMI, HC and RHR1. The multilinear regression model showed a value of r=0.43 in HS_DL, r=0.39 in HS_NDL and r=0.69 in peak Vo2.

CONCLUSION

Although HS and Vo2peak were related to cardiovascular risk markers, Vo2peak offers greater associative power with these cardiovascular risk factors.