Submaximal Endurance Research Articles

Are Ratings of Perceived Exertion during Endurance Tasks of Predictive Value? Findings in Trunk Muscles Require Special Attention.

Background: Subjective rating scales of perceived exertion are often used to quantify effort levels during various endurance exercises, particularly submaximal tasks. The aim of the current study was to determine whether predictive conclusions can be drawn from perceived exertion levels surveyed at the start of defined submaximal endurance tasks. Methods: In this study, healthy participants performed a 10-min endurance task at 50% of their upper body weight, targeting either the back muscles (n = 47, 24 women) or abdominal muscles (n = 32, 17 women). At the end of each minute, participants were asked to rate their perceived exertion (RPE) using the 14-points Borg Scale. Based on their initial and final RPE levels, and for each muscle group separately, participants were divided into subgroups reflecting low (good start/good end) and high (bad start/bad end) strain levels. These values were then compared over the duration of the exercise. Comparisons of RPE levels between subgroups were made using the Mann-Whitney U-test for independent samples, with Bonferroni-Holm correction to account for multiple comparisons. Results: Overall, strain levels increased throughout the duration of the exercise. For the abdominal muscles, the difference between the two RPE groups remained constant over time: participants with good start/end ratings consistently showed different strain levels from those with bad start/end ratings, regardless of whether the grouping was based on initial or final exertion levels. In contrast, for the back muscles, the initial grouping showed a crossover in strain values: by the end of the task, participants in the good start group tended to report higher strain than those in the bad start group. No differences were found in initial RPE values when the grouping was based on final exertion levels. Conclusions: For endurance tasks involving the abdominal muscles, initial strain levels have strong predictive value, whereas this is not the case for the back muscles. Because back muscles are frequently loaded, continuous monitoring of RPE levels is necessary to prevent unexpected task failure, as initial RPE values are not predictive. In contrast, RPE values of 11 or higher on the 14-points Borg scale predict complete exhaustion or even premature task failure with high certainty for abdominal muscle exercises, while lower RPE levels indicate that exercise intensity can be increased.

8-Week Kaempferia parviflora Extract Administration Improves Submaximal Exercise Capacity in Mice by Enhancing Skeletal Muscle Antioxidant Gene Expression and Plasma Antioxidant Capacity.

Black ginger (Kaempferia parviflora) extract (KPE) is extracted from a ginger family plant grown in Thailand. The polyphenolic components have potential antioxidant effects and have been reported to enhance exercise performance. However, the impact of long-term KPE administration combined with long-term training on the endurance exercise performance of healthy individuals has not been fully studied. In this study, a healthy mouse model was used to investigate the effects of 8 weeks KPE administration and voluntary wheel running on the submaximal endurance exercise capacity and its mechanism. The results showed that 8 weeks of KPE administration significantly enhanced the submaximal endurance exercise capacity of mice and extended the daily voluntary wheel running distance. By measuring oxidative stress markers in plasma and the mRNA expression of antioxidant genes in skeletal muscle, we found that KPE significantly increased plasma antioxidant levels and activated the Nrf2 (Nuclear factor erythroid 2-related factor 2)/ARE (Antioxidant Response Element) pathway and its downstream antioxidant genes expression in skeletal muscle. These results suggest that KPE may enhance the antioxidant capacity of plasma and skeletal muscle by activating the Nrf2-ARE-centered antioxidant pathway, thereby increasing the daily running distance and improving the submaximal endurance exercise capacity of mice.

Effects of 4 weeks of device-induced normobaric intermittent hypoxia/hyperoxia training on the performance of elite cyclists: A pilot study

Introduction & Purpose Classic altitude training and other forms of hypoxia are regularly used in endurance training (Mujika et al., 2019). Due to corona exit restrictions in 2019-2020, device-induced normobaric hypoxia/hyperoxia was suggested as an alternative to classic altitude training. Intermittent hypoxia/hyperoxia training (IHHT) has been studied and used in various forms since the 1940s (Serebrovskaya, 2002) with the advantage to be used at the athlete’s training site (Burtscher, 2005). The aim of this pilot study was to test the effects of a IHHT intervention on aerobic performance, hematological parameters and hypoxia-induced factor-1α (HIF-1α). Method A total of 11 athletes (2 women) from the U23 and elite national squads of the Austrian Cycling Federation completed 16 IHHT units in addition to their normal training program over a period of 4 weeks as part of a randomized cross over intervention study (control – IHHT, IHHT – control). The IHHT units were carried out on a Cellgym CellAir® Gecko Plus device at rest without exercise following a predetermined protocol (Sessions 1-8: 5 min of hypoxia (12.0% oxygen) followed by 3 min of hyperoxia (34.0% oxygen) repeated five times. Sessions 9-16): 6 min of hypoxia (11.0% oxygen) followed by 3 min of hyperoxia (34.0% oxygen). During the 4 weeks of control period, participants should maintain their training schedule. Aerobic performance was determined before and after the intervention by spiroergometry. As secondary outcomes, changes in hematological parameters and protein levels of HIF-1α were determined from venous blood which was processed immediately after collection. Serum was stored at -80 °C until HIF-1 α determination by ELISA technique. Results Eleven out of 13 athletes took part in the pre – post IHHT measurements, but only three of them managed to participate in the measurements planned for the control period, making it impossible to compare the two conditions. Replacement was not possible due to the availability of candidates and the ongoing preparation for the season. After 4 weeks of intervention with 16 IHHT training sessions, no significant changes were observed in performance parameters such as VO2peak, relative VO2max, maximum power (watts) or threshold values (p > 0.05). There were also no significant changes in blood enzymes, lipid and iron metabolism (p > 0.05). However, a tendency towards increased values of haemoglobin (z = 1.738; p = 0.082) and a significant increase of erythrocyte counts (z = 2.193; p = 0.028) were detected. Other haematological parameters and HIF-1α did not change significantly (p > 0.05). Discussion & Conclusion In summary, four weeks of device-induced normobaric IHHT had a modest effect on haematological parameters, but with no detectable transfer to maximal or submaximal endurance performance in highly trained athletes. Although various studies have shown that the difference between normobaric and hypobaric hypoxia exposure is not limited to the partial pressure of oxygen, but Mounier and Brugniaux state that the physiological responses are in fact equivalent (Mounier & Brugniaux, 2012). However, due to the limitations of the competitive setting and the low sample size, the final interpretation of the study remains difficult. References Burtscher, M. (2005). Intermittierende Hypoxie: Höhenvorbereitung, Training, Therapie [Intermittent hypoxia: altitude preparation, training, therapy]. Schweizerische Zeitschrift für Sportmedizin und Sporttraumatologie, 53(2), 61-67. Serebrovskaya, T. V. (2002). Intermittent hypoxia research in the former Soviet Union and the commonwealth of independent states: History and review of the concept and selected applications. High Altitude Medicine & Biology, 3(2), 205-221. https://doi.org/10.1089/15270290260131939 Mounier, R., & Brugniaux, J. V. (2012). Counterpoint: Hypobaric hypoxia does not induce different responses from normobaric hypoxia. Journal of Applied Physiology, 112(10), 1784-1786. https://doi.org/10.1152/japplphysiol.00067.2012a Mujika, I., Sharma, A. P., & Stellingwerff, T. (2019). Contemporary periodization of altitude training for elite endurance athletes: A narrative review. Sports Medicine, 49, 1651-1669. https://doi.org/10.1007/s40279-019-01165-y

Impact of probiotic supplementation on exercise endurance among nonelite athletes: a randomized, placebo-controlled, double-blind, clinical trial.

This randomized, placebo-controlled, double-blind, parallel trial investigated whether generally healthy adult, nonelite runners would have a greater time-to-exhaustion during submaximal treadmill running with probiotic versus placebo supplementation. It was hypothesized that the probiotic would impact training progression by reducing gastrointestinal (GI) and cold/flu symptoms. Participants who typically ran ≥24km/week, ran or cross-trained 3-5 days per week, and had a maximal oxygen intake (V̇O2 max) in the 60-85th percentile were enrolled. V̇O2 max was used to establish individualized workload settings (85% of V̇O2 max) for the submaximal endurance tests at baseline and following 6 weeks of supplementation with a probiotic (Lactobacillus helveticus Lafti L10, 5×109 CFU/capsule/day) or placebo. Participants self-reported GI and cold/flu symptoms and physical activity via daily and weekly questionnaires. Outcomes were tested using a linear model to determine if mean response values adjusted for baseline differed between groups. Twenty-eight participants (n=14/group), aged 25±5 years (mean±SD) with a body mass index of 23 ± 3kg/m2, completed the study. At the final visit the probiotic group had a lower time-to-exhaustion versus the placebo group (P=0.01) due to an increase in time-to-exhaustion with the placebo (1344±188 to 1565±219 s, P=0.01) with no change with the probiotic (1655±230 to 1547±215 s, P=0.23). During the intervention, the probiotic group completed fewer aerobic training sessions per week (P=0.02) and trained at a lower intensity (P=0.007) versus the placebo group. Few GI and cold/flu symptoms were reported with no differences between groups. Time-to-exhaustion increased in the placebo group, possibly due to differences in training habits.

Carotid Arterial Compliance during Different Intensities of Submaximal Endurance Exercise.

Background: The purpose of this investigation was to determine the elastic characteristics of the common carotid artery (CCA) during endurance exercise at 3 different intensities. Methods: Twenty young healthy participants (10 males and 10 females) participated in this quasi-experimental cross-sectional study. Participants were tested in two sessions: (1) we took resting measurements of the elastic characteristics of the CCA and performed a cardiopulmonary exercise test (CPET) on a cycle ergometer to determine submaximal exercise intensities, and we conducted (2) measurements of the elastic characteristics of the CCA while exercising in a cycle ergometer at 3 intensities based on blood lactate levels of low (<2 mmol/L), moderate (2-4 mmol/L), and high (>4 mmol/L). Beta stiffness was calculated using CCA diameters during systole and diastole, measured with high-definition ultrasound imaging, and CCA systolic and diastolic pressures were measured via applanation tonometry. Results: Overall, there were no differences between males and females in terms of any of the studied variables (p > 0.05). In addition, no significant changes were found in the CCA beta stiffness and vessel diameter (p > 0.05) between exercise intensities. There was a significant exercise intensity effect on CCA systolic pressure (p < 0.05), but not on CCA diastolic pressure (p > 0.05). Conclusions: The biomechanical characteristics of the CCA, determined via compliance and beta-stiffness, do not change during cyclical aerobic exercise, regardless of exercise intensity.

The oral contraceptive cycle and its influences on maximal and submaximal endurance parameters in elite handball players.

The usage of the oral contraceptive pill is widespread among athletes of various levels. However, there is limited knowledge on how the intake of the pill alters the submaximal and maximal endurance parameters between the oral contraceptive phases. Therefore, the aim of this study was to examine potential differences between the pill intake and withdrawal phase on endurance-related parameters in first-division handball players. In total, 15 female team handball players performed two graded exercise tests until volitional exhaustion on a motorized treadmill. Tests were performed during the pill intake (days 16-17) and withdrawal phase (day 2-3). Throughout the test, respiratory gases were measured breath-by-breath, and the heart rate was measured continuously. Before and after the graded exercise test, blood samples were obtained in order to assess the blood lactate concentration. Before each test, venous blood samples were taken to determine endogenous sex hormone levels. Ventilatory parameters (O2, CO2, and E, and respiratory equivalents for O2 and CO2) were measured, and the oxidation of fat and carbohydrates was calculated. A paired-sample t-test was used to assess differences between the two time points, and the significance was accepted as p < 0.050. Significant differences with lower values during the consumption phase were found for absolute (mean difference ± SD: 88 ± 131mL∙min-1; p = 0.021) and relative O2peak (mean difference ± SD: 1 ± 2mL∙min-1∙kg-1; p = 0.012). Higher values during the consumption phase were found for submaximal respiratory equivalents for O2 (mean difference ± SD: -1.1 ± 1.7; p = 0.028) and CO2 (mean difference ± SD: -0.9 ± 1.5; p = 0.032). No differences were found for all other parameters, including differences for endogenous sex hormones (p > 0.050). The results of the current study suggest only marginal and physiologically insignificant differences in endurance-related parameters between oral contraceptive phases.

Ostarine blunts the effect of endurance training on submaximal endurance in rats

The purpose of this study is to study the effects of ostarine alone and in combination with endurance training in sexually mature, male Wistar rats. The rats were divided into a treadmill-trained group and a sedentary group. Half of each group received either ostarine or vehicle for 8 weeks (n = 10 each, in total n = 40). We examined some functional, hormonal, and anthropometric parameters and the myogenic gene expression of myostatin, insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor-A (VEGF-A) in m. gastrocnemius. Ostarine decreased submaximal endurance and increased myogenic gene expression of myostatin but had no effect on maximal time to exhaustion and grip strength. Training increased submaximal endurance, maximal time to exhaustion, and grip strength. Our results indicate that both exercise and ostarine treatment had no significant effects on serum levels of luteinizing hormone, follicle-stimulating hormone, and testosterone, or on the myogenic gene expression of IGF-1 and VEGF-A. Neither ostarine nor the training had a significant effect on the testis, liver, and heart weights. In conclusion, ostarine had no effect on anthropometric and hormonal parameters but increased the myostatin gene expression in muscle. The SARM treatment decreased submaximal endurance without affecting maximal time to exhaustion, and training increased both metrics.

Performance-Determining Variables of a Simulated Skimo Sprint Competition in Elite Junior Skimo Athletes

This study aimed to investigate the variables determining performance in a simulated on-snow Skimo sprint competition, and how their relationship with performance evolves from the individual time trial to the final. Fifteen national-level junior Skimo athletes (mean ± SD: age, 17.8 ± 2.5 years; maximal oxygen uptake, 66.8 mL·kg−1·min−1) underwent a comprehensive assessment, involving submaximal and maximal endurance tests, maximal strength assessments, and a maximal sprint to determine maximal glycolytic capacity. Subsequently, a simulated sprint competition, comprising an individual time-trial and three heats (quarterfinal, semifinal, final), was conducted. Whole-body and upper body aerobic power (r = 0.69–0.93), maximal speed and power (r = 0.82–0.85) during the maximal performance test, as well as fat-free mass (r = 0.62–0.77) and body fat (r = −0.67–−0.77), exhibited significant correlations with performance in the time-trial, quarterfinal and semifinal. Moreover, maximal strength (r = 0.39–0.95) and transition duration (r = 0.52–0.85) showed moderate to large correlations with sprint performance. Overall, aerobic power, maximal speed and power, as well as fat-free mass, and body fat emerged as crucial determinants of Skimo sprint performance, while dynamic strength and the ability to transition quickly between sections also proved to be relevant factors.

The Effect of Four Weeks of Swimming Training on Insulin Resistance and Hepatokines in Rats with PCOS

Background: Polycystic Ovary Syndrome (PCOS) is a common endocrine and metabolic disorder in women. Several factors are thought to be affected by exercise, including insulin resistance (IR), FGF-21, and PNPLA3. Objectives: This study aimed to determine the effect of swimming training on IR, FGF-21, and PNPLA-3 gene expression in the liver of rats with PCOS. Methods: A total of 24 adult female Wistar rats were divided into four groups: Healthy control group, PCOS control group, healthy exercise group, and PCOS exercise group. Submaximal endurance swimming training was performed using different water flow rates from seven to 15 liters/minute for four weeks, five days per week for 60 minutes. The IR level and expression of FGF-21 and PNPLA3 genes were measured from the liver tissue. Data was analyzed using SPSS software (version 25) and one-way ANOVA (P &lt; 0.05). Results: Based on the results, a significant difference in the amount of IR (P = 0.001), gene expression of FGF-21 (P = 0.001), and PNPLA-3 (P = 0.001) after four weeks of swimming training was decreased. Conclusions: Four weeks of swimming training improves the metabolic pathway and positively affects patients with PCOS.

Differences in Cardiorespiratory Responses with Three Set-Paced Submaximal Endurance Tests in Community-Dwelling Older Adults

Differences in Cardiorespiratory Responses with Three Set-Paced Submaximal Endurance Tests in Community-Dwelling Older Adults

Progressive submaximal effort hamstring muscle endurance is reduced after reconstruction of the anterior cruciate ligament

BackgroundEndurance capability in the muscles controlling the knee is poorly understood post anterior cruciate ligament (ACL) reconstruction, despite many sporting activities requiring notable muscle endurance. The hamstring muscles, when active, provide important anatomical support to protect the reconstructed graft. In the absence of good hamstring endurance, fatigue may predispose individuals to re-injury. ObjectiveTo assess whether ACL reconstruction (ACLR) with a hamstring graft leads to reduced hamstring endurance 9–13 months post-surgery. Study designA cross-sectional inter-limb comparison study was undertaken with participants 9–13 months after an ACLR with a hamstring graft, and a group of age, sex, and activity-matched controls. There were 22 participants in each group. MethodSubmaximal hamstring endurance was measured using a progressive fatigue test on an isokinetic dynamometer at a joint angular velocity of 120°/second. The dependant variable was the maximum number of repetitions performed. Statistical comparisons were made across injured, uninjured and control group limbs. ResultsThere was a significant (p < 0.05) deficit in hamstring endurance observed between the injured leg (mean: 111 repetitions, SD 49) and uninjured leg (mean: 136 repetitions, SD 67) of the ACL group, but not between the uninjured and control group legs (mean: 124 repetitions, SD 50). ConclusionThe 18% deficit in submaximal hamstring endurance across the ACL-reconstructed individual's limbs is indicative of a notable loss in muscle performance at 9–13 months post-surgery. These results provide initial evidence for supporting further research examining the inclusion of hamstring endurance training in ACL rehabilitation programmes post-surgery.

Independent, additive and interactive effects of acute normobaric hypoxia and cold on submaximal and maximal endurance exercise.

To evaluate the independent and combined effects of hypoxia (FiO2 = 13.5%) and cold (-20°C) on physiological and perceptual responses to endurance exercise. 14 trained male subjects ( O2max: 64 ± 5mL/kg/min) randomly performed a discontinuous maximal incremental test to exhaustion on a motorized treadmill under four environmental conditions: Normothermic-Normoxia (N), Normothermic-Hypoxia (H), Cold-Normoxia (C) and Cold-Hypoxia (CH). Performance and physiological and perceptual responses throughout exercise were evaluated. Maximal WorkLoad (WL) and WL at lactate threshold (LT) were reduced in C (-2.3% and -3.5%) and H (-18.0% and -21.7%) compared to N, with no interactive (p = 0.25 and 0.81) but additive effect in CH (-21.5% and -24.6%). Similarly, HRmax and Vemax were reduced in C (-3.2% and -14.6%) and H (-5.0% and -7%), showing additive effects in CH (-7.7% and -16.6%). At LT, additive effect of C (-2.8%) and H (-3.8%) on HR reduction in CH (-5.7%) was maintained, whereas an interactive effect (p = 0.007) of the two stressors combined was noted on Ve (C: -3.1%, H: + 5.5%, CH: -10.9%). [La] curve shifted on the left in CH, displaying an interaction effect between the 2 stressors on this parameter. Finally, RPE at LT was exclusively reduced by hypoxia (p < 0.001), whereas TSmax is synergistically reduced by cold and hypoxia (interaction p = 0.047). If compared to single stress exposure, exercise performance and physiological and perceptual variables undergo additive or synergistic effects when cold and hypoxia are combined. These results provide new insight into human physiological responses to extreme environments.

Whole Body Vibration Training Improves Maximal Strength of the Knee Extensors, Time-to-Exhaustion and Attenuates Neuromuscular Fatigue

Whole-body vibration (WBV) training programs were reported to improve knee extensor muscle (KE) strength in healthy participants. Unfortunately, the underlying mechanisms of these strength gains remain unresolved. In addition, WBV training was shown to increase the time-to-exhaustion of a static submaximal endurance task. However, the effects of WBV training on neuromuscular fatigue (i.e., a decrease of the maximal voluntary isometric contraction; MVIC) induced by an endurance task is unknown. We, therefore, investigated the influence of WBV training on (i) KE MVIC and neuromuscular function, (ii) the time-to-exhaustion of the KE associated with a submaximal isometric fatiguing exercise, and (iii) KE neuromuscular fatigue and its etiology. Eighteen physically active males were assigned to a WBV group (n = 10) or a sham training group (SHAM; n = 8). The MVIC of the KE, voluntary activation, and electrically evoked responses of the KE were assessed (i) before and after a fatiguing exercise (i.e., submaximal isometric contraction) performed until failure, and (ii) before (PRE) and after a 6-week training (POST) period. At POST, the WBV training increased the KE MVIC (+12%, p = 0.001) and voluntary activation (+6%, p &lt; 0.05) regardless of the fatiguing exercise. The time-to-exhaustion was also lengthened at POST in the WBV group (+34%, p &lt; 0.001). Finally, the relative percentage of MVIC decrease after fatiguing exercises diminished in the WBV group between PRE and POST (−14% vs. −6%, respectively, p &lt; 0.001). Significant neural adaptation enhancements account for the trend in KE strength improvements observed after the WBV training program. In addition, the WBV training was effective at increasing the time-to-exhaustion and attenuating neuromuscular fatigue.

The Efficacy of Chlorella Supplementation on Multiple Indices of Cycling Performance

This study investigated the effects of chlorella supplementation on submaximal endurance, time trial performance, lactate threshold, and power indices during a repeated sprint performance test by fourteen male trained cyclists. Participants ingested 6 g/day of chlorella or placebo for 21-days in a double-blinded randomized counter-balanced cross-over design, with a fourteen-day washout period between trials. Each completed a 2-day testing period comprising a 1-hour submaximal endurance test at 55% external power output max and a 16.1 km time trial (Day-1), followed by a lactate threshold (Dmax) and repeated sprint performance tests (3 X 20 s sprints interspersed by 4-mins) (Day-2). Heart rate (b.min−1), RER, V̇O2 (ml·kg−1·min−1), lactate and glucose (mmol/L), time (secs), power output (W/kg), and hemoglobin (g/L) were compared across conditions. Following chlorella supplementation (chlorella vs. placebo for each measurement) average lactate and heart rate were significantly lower (p < 0.05) during submaximal endurance tests (1.68 ± 0.50 mmol/L vs. 1.91 ± 0.65 mmol/L & 138 ± 11b.min−1 vs. 144 ± 10b.min−1), average power and peak power (W/kg) were significantly higher during repeated sprint bouts (9.5 ± 0.7 W/kg vs. 9.0 ± 0.7 W/kg & 12.0 ± 1.2 W/kg vs. 11.4 ± 1.4 W/kg), hemoglobin significantly increased (149.1 ± 10.3 g/L) in comparison to placebo (143.4 ± 8.7 g/L) (p = 0.05). No differences existed between conditions for all oxygen consumption values, 16.1 km time trial measures and lactate threshold tests (p > 0.05). In conclusion, chlorella may pose as an additional supplement for cyclists to consider, particularly for those cyclists who want to improve their sprinting.

Dietary Nitrate Supplementation Enhances Performance and Speeds Muscle Deoxyhaemoglobin Kinetics during an End-Sprint after Prolonged Moderate-Intensity Exercise.

Short-term dietary nitrate (NO3-) supplementation has the potential to enhance performance during submaximal endurance, and short-duration, maximal-intensity exercise. However, it has yet to be determined whether NO3- supplementation before and during submaximal endurance exercise can improve performance during a short-duration, maximal-intensity end-sprint. In a randomised, double-blind, crossover study, 9 recreationally active men ingested NO3--rich (BR: 8 mmol NO3-/day) and NO3--depleted (PL: 0.75 mmol NO3-/day) beetroot powder for 7 days. On day 7, participants completed 2 h of moderate-intensity cycling, which immediately transitioned into a 60 s maximal-intensity end-sprint, with supplements ingested 2 h before and 1 h into the moderate-intensity exercise bout. Plasma [NO3-] and [NO2-] were higher in BR compared to PL pre- and post-exercise (p &lt; 0.05). Post-exercise plasma [NO3-] was higher than pre-exercise (562 ± 89 µM vs. 300 ± 73 µM; p &lt; 0.05) and plasma [NO2-] was not significantly different pre- (280 ± 58 nM) and post-exercise (228 ± 63 nM) in the BR condition (p &gt; 0.05). Mean power output during the final 30 s of the end-sprint was greater after BR (390 ± 38 W) compared to PL (365 ± 41 W; p &lt; 0.05). There were no differences between BR and PL in any muscle oxygenation variables during moderate-intensity cycling (p &gt; 0.05), but muscle [deoxyhaemoglobin] kinetics was faster during the end-sprint in BR (6.5 ± 1.4 s) compared to PL (7.3 ± 1.4 s; p &lt; 0.05). These findings suggest that NO3- supplementation has the potential to improve end-sprint performance in endurance events when ingested prior to and during exercise.

The Relationship Between Fear-Avoidance Beliefs, Disability, and Physical Capacity in Patients with Chronic Low Back Pain.

The objective of this study was to document the multi-dimensional profile of patients referring with chronic low back pain (CLBP) and determine the relationship among fear-avoidance belief and disability and physical capacity in the Pakistani population. A cross-sectional survey was conducted at the Physiotherapy Department of the Institute of Physical Medicine and Rehabilitation, Dow University of Health Sciences. Consecutive sampling was used among the population of CLBP, and objective measures were fear-avoidance beliefs (FABQ-total) and Roland Morris questionnaire (RMDQ) and pain. Each participant performed a physical capacity test, which included a 6-minute walk test (6MWT), abdominal muscular endurance (AME), hand grip strength (HGS), and Functional reach test (FRT). Of the 136 participants, 70(51.5%) were males. The mean and SD of the tests performed were: 6MWT (487.97±51.46), AME (9.31±4.68), FRT (35.14±2.79), HGS (33.31±14.55), VAS (5.51±1.27), RMDQ (18.25±2.17), FABQ-total (48.18±5.31). Multivariate regression revealed that symptom duration, FRT, AME, HGS, VAS, RMDQ were all found to be associated with fear-avoidance belief, accounting for 60% (adjusted R2 = 0.60) of variability. Likewise, only 6-MWT, FRT, FABQ-total were the significant predictors of disability (adjusted R2=0.282). It has been demonstrated that sub-maximal exercise capacity, strength, endurance, pain and flexibility are the contributing factors for the change in disability and fear-avoidance beliefs among the individuals with CLBP. The findings of this study could have inference for increasing productivity both at individual and organizational levels by formulating effective strategies to manage CLBP.

The impact of postexercise blood flow restriction on local muscle endurance of a remote limb.

Studies have examined the influence of postexercise blood flow restriction as a mechanism to activate muscle afferents and assess nonlocal muscle fatigue. Althoughthese studies have assessed fatigue during maximal contractions, less is known about how these afferents may impact submaximal local muscle endurance, which was the purpose of the present study. Individuals completed two testing visits which involved completing a set of elbow flexion exercises to volitional failure on the nondominant followed by the dominant arm. During both trials, a pneumatic cuff was placed at the top of the nondominant arm before exercise. This cuff was inflated to either 0% (control) or 70% (experimental) of the individual's arterial occlusion pressure immediately after the set was completed. We then evaluated how this impacted local muscle endurance of the dominant arm using a Bayesian paired samples t-test with an uninformed prior width of 0.707 centred on 0. A total of 36 individuals completed the study (18 females). There was a greater discomfort present in the experimental trial when compared to the control trial (control: 4.5 standard deviation [SD]: 2.4); experimental: 5.8 [SD: 1.9]; BF10 = 61.46), but there were no differences in repetitions completed on the dominant arm (control: 43 [SD: 9], experimental: 43 [SD: 10]; BF10 = 0.179). Applying blood flow restriction postexercise induced sensations of discomfort but did not alter the local muscle endurance of the contralateral limb. These results suggest that increasing the activation of muscle afferents does not appear to alter the submaximal muscle endurance of a remote limb.

Association of Cardiovascular Risk Markers and Fitness with Task-Related Neural Activity during Animacy Perception.

ABSTRACTPurposeNumerous studies have demonstrated the association between cardiovascular risk markers and fitness, and broad aspects of cognition; however, the possible association of cardiovascular risk markers and fitness with social cognition, which plays a significant role in the development and maintenance of social relationships, has largely been ignored. Herein, we investigated the relationship of cardiovascular risk markers and fitness with task-related neural activity during animacy perception.MethodsWe analyzed data from the Human Connectome Project derived from 1027 adults age 22–37 yr. Canonical correlation analysis (CCA) was conducted to evaluate the association between participants’ body mass index, systolic and diastolic blood pressure, submaximal endurance, gait speed, hand dexterity, and muscular strength with task-related neural activity during animacy perception.ResultsWe observed a single significant CCA mode. Body mass index and blood pressure demonstrated negative cross-loadings with task-related neural activity in the temporoparietal, superior and anterior temporal, posterior cingulate, and inferior frontal regions, whereas submaximal endurance, hand dexterity, and muscular strength demonstrated positive cross-loadings. The observed CCA variates did not seem highly heritable, as the absolute differences in CCA variates in monozygotic twins, dizygotic twins, and nontwin siblings were not statistically different. Furthermore, the cardiovascular risk markers and fitness CCA variates were positively associated with animacy perception and emotion recognition accuracy, which was mediated by the task-related neural activity.ConclusionsThe present findings can provide new insights into the role of markers for cardiovascular health and fitness, specifically their association with social cognition and the underlying neural basis. The intervention for cardiovascular risk and fitness could be a potentially cost-effective method of targeting social cognition.

Resistance training during cardiac rehabilitation improves physical performance in patients with coronary artery disease: a randomised controlled trial

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Slovenian Research Agency Background Resistance training (RT) is an adjunct exercise therapy to aerobic training (AT) in cardiac rehabilitation, but it remains unknown whether the dose-dependent relationship between RT load (high load [HL] vs. low load [LL]) and improvement in anthropometry, body composition and physical performance exists in patients with coronary artery disease (CAD). Purpose The aim of our study was to investigate the effects of HL-RT and LL-RT on top of AT in comparison to AT on anthropometry, body composition and physical performance in patients with CAD. Methods A total of 79 patients with a stable CAD were randomised to HL-RT+AT (n = 21), LL-RT+AT (n = 19) or AT (n = 19) and performed 36 training sessions. Fifty-nine patients with mean (SD) age 61 (8) years and left ventricular ejection fraction 53 (9) % completed the study. AT progressed from 50 % to 80% of peak power output achieved at baseline cardiopulmonary exercise test, and RT progressed from 70% of one repetition maximum (1-RM) to 80% of 1-RM in HL-RT group, and from 35% of 1-RM to 40% of 1-RM in LL-RT group. We measured anthropometry (body mass, waist and hip circumference, and waist to hip circumference ratio), body composition (lean body mass and %, body fat mass and %, and phase angle) and physical performance evaluating upper muscle strength (arm curl and hand grip test) and lower muscle strength (five sit-to stand test, up-and-go test, heel raise test), mobility (gait speed test), flexibility (back scratch test, sit-and-reach test), balance (stork balance test) and submaximal endurance (6 min walk test distance) at baseline and post-training. Results Waist circumference and waist-to-hip circumference ratio decreased significantly following LL-RT (both p &amp;lt; 0.01), without post-training differences between training interventions in other anthropometry measures and body composition measures (all p &amp;gt; 0.079). HL-RT and LL-RT induced improvements in all physical performance measures, while AT alone did not improve gait speed, upper limb flexibility and performance of up-and-go test. HL-RT was associated with greater improvement in gait speed (+12 %, p =0.044), arm curl test (+13 %, p = 0.037) and time of Up-and-go test (+9 %, p &amp;lt;0.001) compared to AT group, while LL-RT improved more time of Up-and-Go test (+18 %, p &amp;lt; 0.001) and time of five sit-to-stands (+14 %, p = 0.016) compared to AT. There was no difference between HL-RT and LL-RT in post-training change of physical performance measures. Conclusions The addition of RT to AT is associated with greater improvements in submaximal muscle strength and mobility compared to AT and should be encouraged in future multimodal exercise-based cardiac rehabilitation.

Inspiratory Muscle Training and Physical Fitness in Children With Down Syndrome: A Randomized Controlled Trial

ObjectiveTo investigate the effect of inspiratory muscle training (IMT) on physical fitness in children with Down syndrome (DS). DesignRandomized control trial. SettingThe study was conducted in a private physical therapy center. ParticipantsForty boys and girls with DS aged between 7 and 10 years were enrolled in this study (N=40). They were randomly and equally divided into 2 groups (A and B). InterventionsAll participants received 30 minutes of aerobic exercise training 3 times per week for 12 weeks, whereas group B received an additional 30 minutes of IMT before each aerobic exercise session. Main Outcomes MeasuresMaximal inspiratory pressure (MIP); maximal expiratory pressure (MEP); submaximal aerobic endurance; muscular strength; endurance. ResultsAmong the group undergoing IMT, there were significant improvements in MIP, MEP, and submaximal aerobic endurance using the six-minute walk test (6MWT); strength and endurance using the curl-up, dumbbell press, trunk lift, standing long jump, seated push-up, pull-up, and flexed-arm hang; and back saver sit and reach tests (P > 0.05). ConclusionsInspiratory muscle training and aerobic exercise training demonstrated more significant improvements in physical fitness than in those children who received only aerobic exercise training.