Incremental Treadmill Test Research Articles

Association between periodontitis and physical fitness in law enforcement workers.

Oral and periodontal health have been linked to systemic health, cardiovascular disease and inflammation markers. Physical fitness has been linked to increased inflammatory response, but only few studies have investigated the association between oral health with physical activity. The aim of this study was to evaluate the association between oral and periodontal health status and physical fitness in British law enforcement workers. 89 subjects were recruited between November and December 2019. Cardiopulmonary fitness was measured by Maximal Oxygen Uptake (VO2max) (ml/kg/min) and Maximum Load (Loadmax) (W) generated at the end of the Bruce incremental treadmill test; physical activity levels through accelerometers; functional strength tests by Countermovement Jump (CMJ) Power (W) and Height (cm) average. Oral variables included percentage of sites with PPD > 4mm (% PPD > 4), full-mouth bleeding score (FMBS) and Decayed, Missing, and Filled Teeth (DMFT) index. Linear regression models were adjusted for age, gender and fat %. Mean age was 41.5 years (range 23-61; 71.9% male). Higher % PPD > 4 was consistently correlated with lower Loadmax (-4.96; p = 0.092), CMJ Height average (-0.39; p = 0.064), and press-ups in 60s (-0.85; p = 0.052) though the associations were not statistically significant. FMBS was associated with the % of a day spent in sedentary (0.78; p = 0.030) and light activities (-0.75; p = 0.022). Periodontitis may be negatively associated with certain components of physical performance. Oral health status may be associated with physical fitness and functional strength.

Effects of Short-Term Low Energy Availability on Metabolism and Performance-Related Parameters in Physically Active Adults.

Low energy availability (LEA) can cause impaired reproductive function, bone health issues, and suppressed immune function, and may result in decreased performance and overall health status. The purpose of this study was to investigate adaptions of body composition, blood status, resting metabolic rate, and endurance performance to gain more comprehensive insights into the symptoms of LEA and the adaptive effects in the athlete population (active women (n = 11) and men (n = 11)). Three treatments were defined as 45 (EA45, control), 30 (EA30), and 10 (EA10) kcal/kg FFM/day and randomly assigned. Pre- and post-intervention measurements were performed through blood sampling, bioelectrical impedance analysis, resting metabolic rate measurement, the oral glucose tolerance test (OGTT), and the incremental endurance test to exhaustion. There was a significant reduction in body weight and fat mass in EA10 compared to EA45 (p ≤ 0.05). Blood serum levels were altered in triglyceride, uric acid, and creatinine concentrations in EA10 compared to EA45 (p ≤ 0.05). Furthermore, blood glucose was still accumulated after 120 min during OGTT in EA10 compared to EA45 (p ≤ 0.05). The respiratory exchange ratio was reduced during submaximal stages of the incremental treadmill test to exhaustion without influencing performance output after treatment EA10 (p ≤ 0.05). However, the resting metabolic rate did not change (p > 0.05). In conclusion, this short-term study indicates that energy restriction can lead to several metabolic-related adaptations, which suggests that the availability and regulation of glucose and fats are significantly influenced after only five days of LEA in physically active women and men. Future research should focus on longer exposures of LEA and sex-specific comparisons (including the menstrual cycle) on LEA symptoms.

Sex differences in exercise-induced arterial hypoxemia and pulmonary edema following high-intensity exercise in highly trained endurance athletes.

This study investigated sex differences in the development of pulmonary edema and exercise-induced arterial hypoxemia (EIAH) in well-trained endurance athletes during near-maximal exercise in a real-world setting. Twenty participants (10M vs. 10F; V̇O2peak: 69.3 (8.8) vs. 50.7 (4.1) ml∙kg-1∙min-1) underwent a maximal incremental treadmill test (visit 1) and a time trial on a steep trail (~2.5 km, ~800 m elevation gain) in North Vancouver (visit 2). Pulmonary edema was evaluated using handheld lung ultrasound ~10-15 min post-exercise and oxygen saturation (SpO2) was monitored using finger pulse oximetry. Males completed the time trial significantly faster than females (M: 31.5 (6.5) vs. F: 40.4 (7.5) min, p = 0.006), while females sustained a higher percentage of their visit 1 heart rate (M: 94 (1) vs. F: 96 (1) %max, p = 0.02). All participants developed EIAH, with no sex differences in end-exercise SpO2 (M: 89 (4) % vs. F: 90 (3) %, respectively, p = 0.35). There was no evidence of pulmonary edema, assessed through ultrasound b-line scores, with no differences between sexes (M: 0.3 (1.0) vs. F: 0.5 (1.5), respectively, p = 0.60). Pulmonary edema is an unlikely contributor to EIAH in endurance athletes performing near-maximal time trial exercise in a real-world setting.

One Shoe to Fit Them All? Effect of Various Carbon Plate Running Shoes on Running Economy in Male and Female Amateur Triathletes and Runners at Individual Training and Race Paces

Carbon plate running shoes (CPRSs) have gained widespread popularity among elite and amateur runners, representing one of the most substantial changes in running gear over the past decade. Compared to elite runners, however, amateurs run at lower speeds and show more diverse running styles. This is a meaningful difference as many previous studies on CPRSs focus either on highly trained male runners and higher speeds or only on a single CPRSs manufacturer. The present study aims at bridging this gap by investigating how CPRSs from four different manufacturers affect running economy in amateurs of both sexes at their individual running speeds. For this purpose, 21 trained amateur triathletes (12 men; 9 women) completed an incremental treadmill test until volitional exhaustion, yielding running speeds at ventilatory thresholds 1 (vVT1) and 2 (vVT2). In a second session, subjects ran five trials of 3 × 3 min (speeds of 90% vVT1, ½ (vVT1 + vVT2), and 100% vVT2), wearing one out of four different pairs of CPRSs or their own preferred non-CPRS shoes in each trial. Our results show that tested CPRS models resulted in a significant reduction in the mean energy cost of transport, compared to the non-CPRS control condition, with Cohen’s d amounting to −1.52 (p = 0.016), 2.31 (p < 0.001), 2.57 (p < 0.001), and 2.80 (p < 0.001), respectively, although effect sizes varied substantially between subjects and running speeds. In conclusion, this study provides evidence that amateur athletes may benefit from various manufacturers’ CPRS models at their typical running speeds to a similar degree as highly trained runners. It is recommended that amateur athletes evaluate a range of CPRSs and select the shoe that elicits the least subjective sensation of fatigue over a testing distance of at least 400–1000 m.

Durability in recreational runners: effects of 90-min low-intensity exercise on the running speed at the lactate threshold.

Recent studies have suggested that the capability to resist deterioration of physiological characteristics could be an independent factor contributing to endurance performance. This study aimed at investigating whether prolonged low-intensity exercise induces shifts in the lactate threshold, and whether fatigue-induced changes differ between the sexes. A total of 31 (15 females) recreational runners performed an incremental treadmill test and a 90-min low-intensity exercise (LIT90) on two separate occasions. The LIT90 was performed at 90% of the first lactate threshold speed (LT1v), derived from the incremental treadmill test. The LT1v was determined from a 5-stage (3min) submaximal threshold test (SubmaxLT), performed before and after LIT90. The SubmaxLTs were followed by a 10/5 reactivity jump test. Respiratory gases, heart rate (HR), and HR-derived detrended fluctuation analysis alpha 1 (DFA-a1) were assessed every 15min during the LIT90. A significant decrease (p < 0.01) was observed in the LT1v in females (-5.8 ± 4.4%) and in males (-5.3 ± 6.4%). The HR increased (p < 0.001) similarly in females (5.9 ± 3.1%) and in males (5.5 ± 3.6%) during the LIT90, while energy expenditure increased (3.1 ± 4.5%, p = 0.013) in females but remained unchanged in males (0.9 ± 3.1%). Change in DFA-a1 during the LIT90 was the only marker that correlated significantly with the relative change of LT1v (r = 0.463, p = 0.013). LIT90 induced significant decreases in the LT1v, and the changes were comparable between sexes. DFA-a1 could be a potential intra-session marker of durability.

Differences in the ventilatory thresholds in treadmill according to training status in 971 males and 301 females: a cross-sectional study.

To analyze the influence of training status on the percentage of maximum oxygen consumption, heart rate and velocity (%VO2max, %HRmax and %Vmax) at which ventilatory threshold 1 and ventilatory threshold 2 occur (VT1 and VT2, respectively), in males and females separately considering age, during a ramp incremental treadmill test. 791 males (36.8 ± 9.9years) and 301 females (33.9 ± 11.0years) performed a ramp incremental exercise test until fatigue where VT1 and VT2 were determined. Participants were classified as low, medium or high training status combining the oxygen consumption at VT1, VT2 and VO2max by clustering analysis. VO2max is poorly correlated with the %VO2max, %HRmax and %Vmax at which VT1 and VT2 occur (r < 0.3), in contrast, there is a positive correlation between oxygen consumption at VT1 and VT2 with the %VO2max, %HRmax and %Vmax at which VT1 and VT2, respectively, occur in males and females (r = 0.203-0.615). Furthermore, we observed the %VO2max, %HRmax and %Vmax at which thresholds occur were greater the higher the training status (all p < 0.003). The physiological determinants of the percentage of maximum at which VT1 and VT2 occur are more related to oxygen consumption at VT1 and VT2, respectively, than to VO2max. Moreover, due to the higher percentage of maximum at which VT1 and VT2 occur in individuals with a higher training status, the common strategy consisting of establishing exercise intensity as a fixed percentage of maximum might not be effective to match intensity across individuals with different training status. NCT06246760.

Differences in acute responses and chronic adaptations according to the exercise intensity reference method in previously inactive individuals

During prolonged continuous exercise, the relationship between external load (e.g., running speed) and internal load [e.g., heart rate (HR)] shifts. This means, for example, that at a given running speed, the HR will continuously increase, whereas if the goal of the exercise is to maintain a constant HR, the running speed will decrease over time. The time dependence of the internal/external load relationship could lead to different acute responses and chronic adaptations depending on the exercise intensity reference method. This hypothesis was tested in the present study. Forty-three previously inactive individuals were randomized into two groups: one group (SPEED-C) trained at a speed midway between the first and second lactate threshold (v ∆ 50LT), whereas the other group (HR-C) trained at a HR midway between the thresholds (HR ∆ 50LT). Both groups performed 30 min of continuous endurance exercise 3 times per week for 8 weeks. Maximal oxygen consumption (V̇O2max) and peak treadmill speed (Vpeak) were determined by an incremental treadmill test followed by a verification test before (PRE) and after (POST) the 8 weeks of training. V̇O2, HR, speed, and rate of perceived exertion (RPE; measured with the Borg CR10) were recorded during the first and last treadmill training sessions performed in the lab. After POST, an additional simulated session was performed with the intensity adjusted to the new training level. Thirty-four participants (9 women and 7 men in SPEED-C; 11 women and 7 men in HR-C) completed the study and were included in the analysis. v ∆ 50LT/HR ∆ 50LT occurred at 74 ± 5% of HRmax, 63 ± 4% of V̇O2max, and 60 ± 4% of V̇peak in SPEED-C and at 74 ± 5 % of HRmax, 63 ± 5% of V̇O2max, and 60 ± 6 % of V̇peak in HR-C. SPEED-C showed higher speed (+1.5 km/h, p &lt; 0.001), V̇O2 (+6.3 mL/kg/min, p &lt; 0.001), HR (+23 bpm, p &lt; 0.001) and RPE (+1.9 points, p = 0.002) than HR-C during the first training session. These initial differences between groups were reduced after 8 weeks of training (speed: by -0.5 km/h, p = 0.006; V̇O2: by -2.6 mL/kg/min, p &lt; 0.001; HR: by -14 bpm, p &lt; 0.001; RPE: (-1.7 points, p = 0.002). However, statistically significant reductions were no longer observed when the intensity was adjusted to the new training level. V̇O2max (+1.0 mL/kg/min, p = 0.021) and Vpeak (+0.8 km/h, p &lt; 0.001) improved more in SPEED-C than in HR-C. Among the secondary physiological characteristics investigated in this study, speed at the second lactate threshold (+1.1 km/h, p &lt; 0.001) and v ∆ 50LT (+0.5 km/h, p = 0.008) improved more in SPEED-C than in HR-C, whereas HR at the second lactate threshold improved more in HR-C than in SPEED-C (-7 bpm, p = 0.008). The exercise intensity reference method (speed vs. HR) affects acute responses and chronic adaptations in previously inactive individuals. However, training conditioning may mitigate these differences if the intensity is not constantly adjusted to the new training level.

Influence of Surgical Mask on Exertion Perception and Select Physiological Parameters During an Incremental Test in Healthy Subjects

Background: During cardiac or pulmonary rehabilitation exercises, the use of a surgical mask may not be well tolerated by patients, especially those experiencing dyspnea during certain activities due to their underlying health conditions. The purpose of this study was to describe the influence of a surgical mask on exertion perception and some physiological parameters during an incremental test in healthy subjects. Methods: A descriptive study involving 16 healthy adult individuals was conducted. The BRUCE incremental protocol was performed twice, with and without the use of a surgical mask. Results: No significant changes were found in vital signs, such as heart rate (p: 0.8684), mean arterial pressure (p: 0.2781), and peripheral oxygen saturation (p: 0.5314). However, the respiratory rate showed a significant difference (p: 0.023). Furthermore, significant differences were observed in the distance covered (p: 0.0005), duration (p: 0.0003), and measured intensity (METs) (p: 0.0117). Metabolic acidosis (p: 0.032), hypocapnia (p: 0.238), and hyperlactatemia (p: 0.024) were detected in the analysis of arterial gases. Oxygenation parameters, such as PaO2 (p: 0.038) and PaO2/FiO2 ratio (p: 0.038), were higher in the mask-off trial. Conclusion: Surgical masks induce negative changes in METs, distance covered, and duration during an incremental treadmill test. Although no significant impact on vital signs was observed, the use of a surgical mask resulted in statistically significant but not clinically relevant decreases in oxygenation parameters. The stages of the Bruce protocol were achieved differently when participants wore a surgical mask. conclusion: During a treadmill incremental test, surgical masks induce negative changes in MET, distance covered, and duration. Although no significant impact was observed on vital signs, wearing a surgical mask resulted in statistically significant but not clinically relevant decreases in oxygenation parameters. The stages of the Bruce protocol were achieved differently when participants wore a surgical mask.

Long-Term Effects of Three Different Exercise Training Modes on Cardiorespiratory Fitness of Female Flamenco Dancers.

It is well established that high-intensity interval training (HIIT) is effective in enhancing athletes' performance and improving the health of recreational exercisers. However, there is a dearth of comprehensive recommendations regarding the integration of HIIT into the exercise routines of flamenco dancers. Therefore, this study aimed to evaluate how three different 10-week training programs--including traditional flamenco training (control group, CG) alone or combined with HIIT or muscular strength and endurance training (MSET)--impact the cardiovascular fitness (maximal oxygen consumption, VO2max) of female flamenco dancers, specifically focusing on the effectiveness of additional training methods. A group of 33 trained female flamenco dancers was randomly divided into three groups: HIIT (n=11), MSET (n=11), and a control group (CG, n=11). VO2max was assessed through breath-by-breath gas analysis during an incremental treadmill test. All participants, including the control group, engaged in uniform choreography sessions at moderate intensity (55-60% of reserve heart rate [HRR], 50 min/day, twice a week). In addition, the HIIT and MSET groups underwent supplementary training sessions twice a week (40 min/day) for 10 weeks, utilizing different techniques and intensities (HIIT: 80-90% of HRmax; MSET: 55-75% of HRmax). A statistically significant 19.7% improvement in aerobic capacity (VO2max) was observed in the HIIT group (p≤0.05), with large effect sizes (ES) compared to MSET (p=0.011; ES=2.423) and CG (p=0.034; ES=1.664). These findings indicate that HIIT training, when integrated with dance lessons, enhances aerobic capacity more effectively compared to traditional dance training alone or traditional dance training supplemented with MSET. Therefore, integrating HIIT into dance training programs as supplementary training may be particularly effective in improving aerobic capacity for female flamenco dancers.

Test-Retest Reliability of Running Economy and Metabolic and Cardiorespiratory Parameters During a Multistage Incremental Treadmill Test in Male Middle- and Long-Distance Runners.

This study investigated the test-retest reliability of running economy (RE) and metabolic and cardiorespiratory parameters related to endurance running performance using a multistage incremental treadmill test. On two occasions separated by 21-28days, 12 male middle- and long-distance runners ran at 10, 11, 12, 13, and 14km/hr for 8min each stage, immediately followed by a ramp test to volitional exhaustion. Carbohydrate (10% maltodextrin solution) was consumed before and during the test to provide ∼1g/min of exercise. RE, minute ventilation (V˙E), oxygen consumption (V˙O2), carbon dioxide production (V˙CO2), respiratory exchange ratio(RER), heart rate(HR), ratings of perceived exertion(RPE), and blood glucose and lactate concentrations were recorded for each stage and at volitional exhaustion. Time-to-exhaustion (TTE) and peak oxygen consumption (V˙O2peak) during the ramp test were also recorded. Absolute reliability, calculated as the coefficient of variation (CV) between repeated measures, ranged from 2.3% to 3.1% for RE, whereas relative reliability, calculated as the intraclass correlation coefficient(ICC), ranged from .42 to .79. V˙E, V˙O2, V˙O2peak, V˙CO2, RER, and HR had a CV of 1.1%-4.3% across all stages. TTE and RPE had a CV of 7.2% and 2.3%-10.8%, respectively, while glucose and lactate had a CV of 4.0%-17.8%. All otherparameters, except for blood glucose, were demonstrated to have good-to-excellent relative reliability assessed by ICC. Measures of RE, V˙O2peak, and TTE were reliable during this two-phase multistage incremental treadmill test in a cohort of trained and highly trained male middle- and long-distance runners.

Combined intermittent hypoxic exposure at rest and continuous hypoxic training can maintain elevated hemoglobin mass after a hypoxic camp.

Athletes use hypoxic living and training to increase hemoglobin mass (Hbmass), but Hbmass declines rapidly upon return to sea level. We investigated whether intermittent hypoxic exposure (IHE) + continuous hypoxic training (CHT) after return to sea level maintained elevated Hbmass, and if changes in Hbmass were transferred to changes in maximal oxygen uptake (V̇o2max) and exercise performance. Hbmass was measured in 58 endurance athletes before (PRE), after (POST1), and 30 days after (POST2) a 27 ± 4-day training camp in hypoxia (n = 44, HYP) or at sea level (n = 14, SL). After returning to sea level, 22 athletes included IHE (2 h rest) + CHT (1 h training) in their training every third day for 1 mo (HYPIHE + CHT), whereas the other 22 HYP athletes were not exposed to IHE or CHT (HYPSL). Hbmass increased from PRE to POST1 in both HYPIHE + CHT (4.4 ± 0.7%, means ± SE) and HYPSL (4.1 ± 0.6%) (both P < 0.001). Compared with PRE, Hbmass at POST2 remained 4.2 ± 0.8% higher in HYPIHE + CHT (P < 0.001) and 1.9 ± 0.5% higher in HYPSL (P = 0.023), indicating a significant difference between the groups (P = 0.002). In SL, no significant changes were observed in Hbmass with mean alterations between -0.5% and 0.4%. V̇o2max and time to exhaustion during an incremental treadmill test (n = 35) were elevated from PRE to POST2 only in HYPIHE + CHT (5.8 ± 1.2% and 5.4 ± 1.4%, respectively, both P < 0.001). IHE + CHT possesses the potential to mitigate the typical decline in Hbmass commonly observed during the initial weeks after return to sea level.NEW & NOTEWORTHY Sets of 2-h intermittent hypoxic exposure + 1-h continuous hypoxic training, every third day, possess the potential to mitigate the typical decline in Hbmass that is commonly observed during the initial weeks after return to sea level from an altitude camp. Inclusion of IHE + CHT in the training regimen was also accompanied by improvements in V̇o2max and exercise performance in most but not all Tier 3-Tier 5 level endurance athletes during the training season.

Validation of field-based running tests to determine maximal aerobic speed in professional rugby league.

Practitioners place importance on high-speed running (HSR) to monitor training practice and match-play demands, whilst attempting to maximise fitness and minimize the risk of injury occurrence. Practitioners apply various methods to quantify HSR, such as absolute thresholds, percentage of maximum sprint speed and maximal aerobic speed (MAS). A recent survey demonstrates the 5-minute run and 1200m shuttle test (ST) to be implemented among rugby league practitioners to quantify HSR by incorporating MAS. However, it is unclear as to how valid these methods are to accurately quantify MAS. Therefore, the aim of this study was to assess the validity of the 5-minute run and 1200m ST when compared to a gold standard measure for MAS. Twenty 1st team professional rugby league players competing in the European Super League participated in this study. Players were required to complete an incremental treadmill test, 5-minute run and 1200m ST over a two-week period in pre-season. MAS, peak heart rate (HRmax), peak lactate (Lapeak) and rating of perceived exertion (RPE) where collected upon completion of each test. Results demonstrated the 1200m ST to have a higher correlation for MAS than the 5-minute run (1200m ST: r = 0.73, 5-minute run: r = 0.64). However, when assessing validity using the level of agreement between data, the 5-minute run underreported MAS by 0.45 m·s-1 whereas the 1200m ST underreported MAS by 0.77 m·s-1. Ultimately, both field-based tests used in this study underreport MAS when compared to an incremental treadmill test, although the 5-minute run provides a closer agreement and therefore a more valid measurement for MAS than the 1200m ST.

Reassembling the Field-based Applicability of the Lactate Threshold for Old Age.

This study aimed to investigate the applicability of the Lactate Threshold (LT) to predict maximal oxygen uptake (˙VO2max) and demarcate the boundary between the moderate- to heavy-intensity domain (HRm-h) in old age in comparison to the most utilized methods. A cross-sectional validation study was conducted. Participants aged 61 to 77 performed a familiarization procedure, an incremental maximal exercise treadmill test (CPX) for ˙VO2max determination, the Six-minute Walk Test (6MWT), and a discontinuous incremental field test for LT determination. Lower (P<0.01) internal effort was required for LT testing (76±8%HRmax) compared to 6MWT (92±9%HRmax). The application of the 6MWT reference equations overestimated ˙VO2max by 10-23%. LTs better estimated the ˙VO2max (r ≈0.90, SEE: ≈3.0] compared to the 6MWT (r=0.68, SEE=5.5). HRm-h determined by the CPX differed (20%; P=0.001) from that obtained by LT. HRm-h stratification indicated participants fall into the very light to the vigorous intensity domains. LT testing is more submaximal than the 6MWT, and is a valuable tool to estimate the ˙VO2max in older male adults. Implementation of LT testing in physical activity programs might help improving the quality of aerobic exercise training in older men.

Mitochondria Transplantation: Rescuing Innate Muscle Bioenergetic Impairment in a Model of Aging and Exercise Intolerance.

Arroum, T, Hish, GA, Burghardt, KJ, Ghamloush, M, Bazzi, B, Mrech, A, Morse, PT, Britton, SL, Koch, LG, McCully, JD, Hüttemann, M, and Malek, MH. Mitochondria transplantation: Rescuing innate muscle bioenergetic impairment in a model of aging and exercise intolerance. J Strength Cond Res 38(7): 1189-1199, 2024-Mitochondria, through oxidative phosphorylation, are crucial for energy production. Disease, genetic impairment, or deconditioning can harm muscle mitochondria, affecting energy production. Endurance training enhances mitochondrial function but assumes mobility. Individuals with limited mobility lack effective treatments for mitochondrial dysfunction because of disease or aging. Mitochondrial transplantation replaces native mitochondria that have been damaged with viable, respiration-competent mitochondria. Here, we used a rodent model selectively bred for low-capacity running (LCR), which exhibits innate mitochondrial dysfunction in the hind limb muscles. Hence, the purpose of this study was to use a distinct breed of rats (i.e., LCR) that display hereditary skeletal muscle mitochondrial dysfunction to evaluate the consequences of mitochondrial transplantation. We hypothesized that the transplantation of mitochondria would effectively alleviate mitochondrial dysfunction in the hind limb muscles of rats when compared with placebo injections. In addition, we hypothesized that rats receiving the mitochondrial transplantation would experience an improvement in their functional capacity, as evaluated through incremental treadmill testing. Twelve aged LCR male rats (18 months old) were randomized into 2 groups (placebo or mitochondrial transplantation). One LCR rat of the same age and sex was used as the donor to isolate mitochondria from the hindlimb muscles. Isolated mitochondria were injected into both hindlimb muscles (quadriceps femoris, tibialis anterior (TA), and gastrocnemius complex) of a subset LCR (n = 6; LCR-M) rats. The remaining LCR (n = 5; LCR-P) subset received a placebo injection containing only the vehicle without the isolated mitochondria. Four weeks after mitochondrial transplantation, rodents were euthanized and hindlimb muscles harvested. The results indicated a significant (p < 0.05) increase in mitochondrial markers for glycolytic (plantaris and TA) and mixed (quadricep femoris) muscles, but not oxidative muscle (soleus). Moreover, we found significant (p < 0.05) epigenetic changes (i.e., hypomethylation) at the global and site-specific levels for a key mitochondrial regulator (transcription factor A mitochondrial) between the placebo and mitochondrial transplantation groups. To our knowledge, this is the first study to examine the efficacy of mitochondrial transplantation in a rodent model of aging with congenital skeletal muscle dysfunction.

Validity, reliability, and the contributing physical characteristics of a modified 15m prone Yo-Yo Intermittent Recovery Test Level-1 test in elite female rugby league players.

This study aims to establish the validity and reliability of the prone Yo-YoIRL1 in elite female rugby league players (part one) and determine the anthropometric and physical characteristics contributing to 15m prone Yo-YoIRL1 performance (part two). Part one, 21 subjects completed one Yo-YoIRL1, one 20m and two 15m prone Yo-YoIRL1 tests over four sessions, with 7-14 days in-between. Part two, ten subjects completed a testing battery, including body mass, height, dual-energy x-ray absorptiometry, isometric mid-thigh pull, isometric bench-press, 10m and 20m sprints and an incremental treadmill test ([Formula: see text]). The 15m prone YoYoIRL1 demonstrated poor reliability with a typical error of 68m (21%) and a smallest worthwhile change of 54m (9%). Validity analysis found the prone versions of the YoYoIRL1 were not sensitive measures of intermittent running performance. Both prone YoYoIRL1 test distances demonstrated large mean bias (76% and -37% respectively) and typical error of the estimate (19% and 21%, respectively) in comparison to the YoYoIRL1. Body mass (r = -0.89), lean mass (r = -0.64), body fat % (r = -0.68), [Formula: see text] (l∙min-1) (r = -0.64), IMTP (r = -0.69), IBP (r = -0.15), 10m (r = -0.77) and 20m (r = -0.72) momentum displayed large negative relationships with 15m prone Yo-YoIRL1 performance. Due to the poor validity of the 20m prone YoYoIRL1, the poor validity and reliability of the 15m prone YoYoIRL1, and the anthropometric and physical characteristics which negatively impact performance, practitioners should reconsider the use of the prone YoYoIRL1 test to monitor high intensity intermittent running performance.

Differences and relationship between velocity attained at VO2max and time trial performances in Para athletes with vision impairment and their guides

The aim of this study was to compare the relationship and difference between velocity attained at maximal oxygen consumption (vVO2max) and 1000-m time trials in Para athletes with vision impairment and their guides. This study had seven Para athletes of class T11 (six Paralympic Games medalists and one non-medalist) and seven respective guides who performed an incremental treadmill test and 1000-m time trial on the athletics track. Data normality was checked through the Shapiro-Wilk test, Student t test, and effect size (ES) to compare differences between groups, and the association between vVO2max and time trial mean velocity (vTT) was made through linear regression. No differences were observed ( p = .555, ES: 0.236) in the VO2max of the T11 athletes (49.29 ± 9.25 ml kg−1 min−1) and their respective guides (51.30 ± 8.92 ml kg−1 min−1), as well as in the vVO2max (T11 athlete: 18.14 ± 3.53 km h−1, guide: 19.00 ± 2.52 km h−1, p = .585, ES: 0.218) and vTT (T11 athlete: 17.25 ± 3.57 km h−1, guide: 20.12 ± 2.25 km h−1, p = .100, ES: 0.735). However, the linear regression analysis between vVO2max and vTT revealed a positive and moderate relationship in T11 athletes (R2 = 0.684, p &lt; .01) and a very large guide (R2 = 0.774, p &lt; .01). The speed reserve of the guide in relation to the T11 athlete was 16%. The results of vTT underestimate the vVO2max more in guides than in T11 athletes.

Longitudinal changes in anthropometric, physiological, and physical qualities of international women's rugby league players.

This is the first study to assess longitudinal changes in anthropometric, physiological, and physical qualities of international women's rugby league players. Thirteen forwards and 11 backs were tested three times over a 10-month period. Assessments included: standing height and body mass, body composition measured by dual x-ray absorptiometry (DXA), a blood panel, resting metabolic rate (RMR) assessed by indirect calorimetry, aerobic capacity (i.e.,[Formula: see text]) evaluated by an incremental treadmill test, and isometric force production measured by a force plate. During the pre-season phase, lean mass increased significantly by ~2% for backs (testing point 1: 47 kg; testing point 2: 48 kg) and forwards (testing point 1: 50 kg; testing point 2: 51 kg) (p = ≤ 0.05). Backs significantly increased their [Formula: see text] by 22% from testing point 1 (40 ml kg-1 min-1) to testing point 3 (49 ml kg-1 min-1) (p = ≤ 0.04). The [Formula: see text] of forwards increased by 10% from testing point 1 (41 ml kg-1 min-1) to testing point 3 (45 ml kg-1 min-1), however this change was not significant (p = ≥ 0.05). Body mass (values represent the range of means across the three testing points) (backs: 68 kg; forwards: 77-78 kg), fat mass percentage (backs: 25-26%; forwards: 30-31%), resting metabolic rate (backs: 7 MJ day-1; forwards: 7 MJ day-1), isometric mid-thigh pull (backs: 2106-2180 N; forwards: 2155-2241 N), isometric bench press (backs: 799-822 N; forwards: 999-1024 N), isometric prone row (backs: 625-628 N; forwards: 667-678 N) and bloods (backs: ferritin 21-29 ug/L, haemoglobin 137-140 g/L, iron 17-21 umol/L, transferrin 3 g/L, transferring saturation 23-28%; forwards: ferritin 31-33 ug/L, haemoglobin 141-145 g/L, iron 20-23 umol/L, transferrin 3 g/L, transferrin saturation 26-31%) did not change (p = ≥ 0.05). This study provides novel longitudinal data which can be used to better prepare women rugby league players for the unique demands of their sport, underpinning female athlete health.

Acute physiological and psychological responses during an incremental treadmill test wearing a new upper-body sports garment with elastomeric technology.

Background: The use of elastomeric technology in sports garments is increasing in popularity; however, its specific impact on physiological and psychological variables is not fully understood. Thus, we aimed to analyze the physiological (muscle activation of the pectoralis major, triceps brachii, anterior deltoid, and rectus abdominis, capillary blood lactate, systolic and diastolic blood pressure, and heart rate) and psychological (global and respiratory rating of perceived exertion [RPE]) responses during an incremental treadmill test wearing a new sports garment for the upper body that incorporates elastomeric technology or a placebo garment. Methods: Eighteen physically active young adults participated in two randomized sessions, one wearing the elastomeric garment and the other wearing a placebo. Participants performed in both sessions the same treadmill incremental test (i.e., starting at 8km/h, an increase of 2km/h each stage, stage duration of 3min, and inclination of 1%; the test ended after completing the 18km/h Stage or participant volitional exhaustion). The dependent variables were assessed before, during, and/or after the test. Nonparametric tests evaluated differences. Results: The elastomeric garment led to a greater muscle activation (p < 0.05) in the pectoralis major at 16km/h (+33.35%, p = 0.01, d = 0.47) and 18km/h (+32.09%, p = 0.02, d = 0.55) and in the triceps brachii at 10km/h (+20.28%, p = 0.01, d = 0.41) and 12km/h (+34.95%, p = 0.04, d = 0.28). Additionally, lower lactate was observed at the end of the test (-7.81%, p = 0.01, d = 0.68) and after 5min of recovery (-13.71%, p < 0.001, d = 1.00) with the elastomeric garment. Nonsignificant differences between the garments were encountered in the time to exhaustion, cardiovascular responses, or ratings of perceived exertion. Conclusion: These findings suggest that elastomeric garments enhance physiological responses (muscle activation and blood lactate) during an incremental treadmill test without impairing physical performance or effort perception.

Acute physiological, biomechanical, and perceptual responses of runners wearing downward-curved carbon fiber insoles.

In a randomized controlled cross-over study ten male runners (26.7 ± 4.9 years; recent 5-km time: 18:37 ± 1:07 min:s) performed an incremental treadmill test (ITT) and a 3-km time trial (3-km TT) on a treadmill while wearing either carbon fiber insoles with downwards curvature or insoles made of butyl rubber (control condition) in light road racing shoes (Saucony Fastwitch 9). Oxygen uptake, respiratory exchange ratio, heart rate, blood lactate concentration, stride frequency, stride length and time to exhaustion were assessed during ITT. After ITT, all runners rated their perceived exertion, perceived shoe comfort and perceived shoe performance. Running time, heart rate, blood lactate levels, stride frequency and stride length were recorded during, and shoe comfort and shoe performance after, the 3-km TT. All parameters obtained during or after the ITT did not differ between the two conditions [range: p = 0.188 to 0.948 (alpha value: 0.05); Cohen's d = 0.021 to 0.479] despite the rating of shoe comfort showing better scores for the control insoles (p = 0.001; d = -1.646). All parameters during and after the 3-km TT showed no differences (p = 0.200 to 1.000; d = 0.000 to 0.501) between both conditions except for shoe comfort showing better scores for control insoles (p = 0.017; d = -0.919). Running with carbon fiber insoles with downwards curvature did not change running performance or any submaximal or maximal physiological or biomechanical parameter and perceived exertion compared to control condition. Shoe comfort is impaired while running with carbon fiber insoles. Wearing carbon fiber insoles with downwards curvature during treadmill running is not beneficial when compared to running with control insoles.

Seasonal Variation and the Effect of the Transition Period on Physical Fitness Parameters in Youth Female Soccer Players.

This study examined seasonal variation and the effect of the transition period on physical fitness parameters in female youth soccer players. Twenty-four players (13-17 years old) were assessed through field and laboratory testing. They completed laboratory testing three times: (1) at the beginning of the season (post-preseason), (2) at the end of the regular season (postseason), and (3) following the transition period (preseason). Field testing was conducted post-preseason and postseason. Results indicated that weight and body fat significantly increased from post-preseason to postseason and following the transition period. A paired samples T-test revealed that the players performed significantly better in the vertical jump and 30 m sprint test (all p < 0.01) postseason compared to post-preseason. Also, it was indicated that torque production for the right quadriceps, left quadriceps, and right hamstring (all p < 0.01) was significantly reduced after the transition period by 10%, 11.8%, and 10.5%, respectively. Cardiorespiratory measurements demonstrated that performance on an incremental cardiopulmonary treadmill test, maximal oxygen consumption, velocity at the first ventilatory threshold, velocity at the second ventilatory threshold, and velocity at maximal oxygen consumption (all p < 0.01) were significantly reduced postseason and following the transition period. Based on the results, coaches and trainers should primarily focus on maintaining the aerobic capacity of the players during the season, as it has been indicated to be reduced from the beginning to the end of the competitive period (VO2max reduced by 3.3%). In addition, they should focus on maintaining lower body strength and aerobic capacity during the transition period.