International journal of exercise science最新文献

Smartpaddle^® is a novel wearable device based on inertial measurement units (IMU) for in-field arm-stroke kinetics and kinematics analysis in swimming. However, the lack of data regarding its agreement and reliability, coupled with restricted access to raw data, emphasizes the need to evaluate it against a well-established strain gauge (SG) reference method for assessing swimming forces. Thus, this study aimed to investigate the agreement and reliability between the Smartpaddle^® and strain gauge in a 30-s all-out arms-only tethered swimming test. Twelve trained young adult swimmers performed a test-retest 30-s all-out arms-only tethered swimming trial. Peak and mean forces were obtained from IMU (PF_IMU and MF_IMU) and SG (PF_SG and MF_SG) simultaneously. Statistical differences and correlations were found in both peak (PF_SG = 158.46 ± 48.85 N, PF_IMU = 75.47 ± 12.05 N, p < 0.001, r = 0.88) and mean (MF_SG = 69.62 ± 16.36 N, MF_IMU = 30.06 ± 5.42 N, p < 0.001, r = 0.84) forces between devices, presenting elevated systematic errors for both variables. No differences were found in IMU data between test-retest conditions in both peak (PF_IMU = 75.47 ± 12.05 N, PF_IMU = 75.45 ± 11.54 N, p = 0.99, ICC = 0.96) and mean (MF_IMU = 30.06 ± 5.42 N, MF_IMU = 30.21 ± 5.83 N, p = 0.80, ICC = 0.95) forces, with negligible systematic errors. In conclusion, although the Smartpaddle® device is not directly comparable to the strain gauge reference method, it has demonstrated high reliability levels in test-retest trials.

The purpose of this study was to observe if core stabilization training plays a significant role in firefighter time-to-completion during a functional performance test. A within subjects study design was used in which subjects (n = 13, 84.6% male, 33.7 ± 7.4 years of age, 91.06 ± 13.29 kg, 25.79 ± 6.55 percent body fat, 8.96 ± 7.51 years of firefighting experience) completed two performance tests (pre and post core training), comprised of 7 firefighter-specific exercises performed while wearing a 22.68 kg weight vest to mimic typical firefighter equipment. Between testing sessions, subjects were prescribed specific core stabilization exercises to perform at least three days a week for a total of 4 weeks. Time-to-completion was significantly quicker between the first (300.89 ± 42.11s) and second (256.92 ± 34.31s) performance testing, on average by 43.8 seconds (p < 0.001). Body mass index (p = 0.065) and rating of perceived exertion during testing (p = 0.084) did not significantly decrease across the course of the study. Adequate fitness is essential to firefighters' job task performance. Data from this study suggests that regular core stabilization training may assist in optimizing the effectiveness, and potentially safety, of firefighters' performance in high intensity functional skills.

Reliably determining vertical jump (VJ) take-off on a force plate is crucial when identifying performance-related biomechanical factors. Therefore, the purpose of this study was to compare several take-off thresholds (20 N, 10 N, 5 N, 1 N, five standard deviations above an unloaded force plate (5SD), and peak residual force (PkRes) produced when the force plate was unloaded) in terms of jump height (JH), movement time (MT), reactive strength index modified (RSImod), net impulse (netIMP), and propulsive impulse (prIMP). Twenty-one participants performed five countermovement VJs on a force plate. All thresholds were reliable with intraclass correlations ≥ 0.835 and coefficient of variation < 10%. Our results show significant differences across the different take-off thresholds for JH, MT, RSImod, netIMP, and prIMP. However, these differences were considered trivial based on effect sizes. While differences in these thresholds may not be practically meaningful, practitioners are encouraged to consider the noise in the force-time signal and select an appropriate threshold that matches PkRes within their given environment.

Alcohol has previously shown a paradoxical positive relationship with exercise behaviors. However, the relationship has not been explored according to type of exercise (aerobic vs. anaerobic), nor has the research considered other contextual variables that commonly co-occur with alcohol use, such as cannabis and mood. This study sought to expand upon previous research to understand how the alcohol-exercise relationship may vary based on exercise type. Additionally, this study included cannabis use and mood as moderators of the alcohol-exercise association. Cross-sectional survey data was collected from college students (N = 335). Negative binomial regression was used to test associations between exercise and alcohol consumption, cannabis use, positive affect (PA), negative affect (NA), and moderating effects of these factors on the alcohol-exercise relationship. Effect sizes are reported from an Incidence Rate Ratio (IRR). Sex assigned at birth (male = 1, female = 0; IRR = 1.34, p = .017), PA (IRR = 1.57, p = .001), and alcohol consumption (IRR = 1.94, p = .037) exhibited positive relationships with exercise. Significant main effects were not observed for negative affect (IRR = 1.17, p = .230), or cannabis use (IRR = 1.00, p = .988). There was a significant interaction between positive affect and alcohol consumption (IRR = 0.87, p = .044) predicting exercise minutes. Alcohol was positively associated with exercise for those with low positive affect (n = 42, b = 12.61, p = .096) and this effect was attenuated as levels of positive affect increased (mean positive affect: n = 232, b = 0.55, p = .926; high positive affect: n = 61, b = -15.86, p = .146). These findings suggest that low positive affect may contribute to the positive link between alcohol use and exercise (especially aerobic exercise) in young people.

Maximal oxygen consumption (V̇O_2max) is an important measure of aerobic fitness, with applications in evaluating fitness, designing training programs, and assessing overall health. While treadmill assessments are considered the gold standard, airbikes (ABs) are increasingly popular exercise machines. However, limited research exists on AB-based V̇O2max assessments, particularly regarding agreement with treadmill graded exercise tests. To address this gap, a randomized crossover study was conducted, involving 15 healthy adults (9M, 6F, 7 familiar with AB) aged 30.1 ± 8.6 years. Paired t-tests, intraclass correlation coefficients (ICC), Bland-Altman and Principal component (PC) analyses were used to assess agreement between protocols. The results demonstrated good to excellent agreement in V̇O_2max, maximum heart rate (HR), and rating of perceived exertion (ICC range: 0.89-0.92). However, significant differences were observed in several measures, including V̇O_2max and maximum HR (p < 0.01). Overall a systematic bias 3.31 mL/kg/min (treadmill > AB, 95%CI[1.67,4.94]) was observed, no proportional bias was present; however, regular AB users (systematic bias: 1.27 (95%CI[0.20,2.34]) mL/kg/min) exhibited higher agreement in V̇O_2max measures compared to non-regular users (systematic bias: 5.09 (95%CI[3.69,6.49]) mL/kg/min). There were no significant differences in cardiorespiratory coordination, between the AB and the treadmill. These findings suggest that for individuals familiar with the AB, it can be a suitable alternative for assessing V̇O_2max compared to the treadmill. Future research with larger samples should focus on developing prediction equations for field AB tests to predict V̇O_2max. Practitioners should consider using the AB to assess V̇O_2max in individuals who prefer it over running.

Falls are the leading cause of injury-related deaths among older adults and affect women at disproportionate rates. Dance has been used to improve postural stability, balance confidence and strength of older adults, but in-person classes are often inaccessible. This quasi-experimental pre-mid-post design study investigates whether 12 weeks of online dance classes can improve postural stability, dynamic balance and strength of women aged 65 plus. 16 participants (median=74 years, IQR=6) recruited via convenience sampling completed 12 weeks of twice weekly 75-minute online dance classes. In-person pre, mid and post assessments used 30-second trials of quiet standing, Star Excursion Balance Test, 30-second Sitto-Stand and Calf-Raise-Senior. Significance was evaluated using Friedman's test with Wilcoxon Signed-Rank test post-hoc (p≤.05). Participants demonstrated a high attendance rate (median=87.5, IQR=4.2%). Decreased mediolateral sway was observed pre-mid in eyes closed (p=.003, r=.76) and foam (p=.02, r=.60) conditions, where the latter also produced decreased sway area (p=.015, r=.63). Greater dynamic balance was demonstrated when reaching laterally (pre-mid p=.008, r=.68; pre-post p=.008, r=.69) and posterior-laterally (pre-post p=.009, r=.75). Participants significantly improved their number of repetitions on the Calf-Raise Senior (mid-post p=.02, r=.60; prepost p=.015, r=.63). Online dance classes are engaging, accessible and effective in decreasing older women's risk of falls and maintaining their independence.

Objective: The main objective was to ascertain the acute responses in autonomic nervous activity and peripheral sensation induced by moderate-intensity treadmill exercise performed under different ambient temperatures.

Methods: Twelve young healthy subjects underwent three sessions of moderate-intensity treadmill exercise (warming, 5 min and running, 25 min), on different days under 10°C, 20°C and 30°C room temperatures. Pre- and post-intervention, heart rate variability (HRV) and plantar vibrotactile perception threshold (VPT) were measured. Additionally, rate of perceived exertion (RPE) was recorded after intervention.

Results: In comparison with the corresponding baseline values, after intervention, low frequency power (LF) and LF/high frequency power (HF) of HRV increased significantly and HF decreased significantly under the condition of 10°C only (p < .005). Following intervention, VPT increased significantly at the hallux for 31.5 Hz test frequency under 30°C and at the heel for 31.5 Hz test frequency under 10°C (both p < .05). In contrast, VPT decreased significantly at the hallux for 125 Hz test frequency under 10°C (p < .005). Exposure under the temperature of 20°C did not result in any significant change in VPT. After intervention, RPE under 30°C showed significantly higher values than those under 20°C (p < .01) and 10°C (p < .005) conditions with no difference between the latter two conditions.

Conclusions: Treadmill exercise under 20°C ambient temperature did not exert any negative impacts on autonomic and peripheral nerve function and resulted in a perceived exertion of moderate intensity among the study participants. Therefore, an ambient temperature around 20°C might be recommended for the mentioned purpose.

The 'loaded carry' is a popular resistance training activity that activates core musculature across multiple movement planes while the body is in locomotion. 'Hold' exercises are similar to carry exercises but lack the locomotive aspect. Both carry and hold exercises can be completed bilaterally (farmer's carry (FC) and hold (FH)) or unilaterally (suitcase carry (SC) and hold (SH)). A deeper understanding of muscle activation between the FC and SC and intensity-matched FH and SH might improve their application. Healthy, college-aged individuals were recruited and surface electromyography of the rectus abdominis (RA), external oblique (EO), longissimus (LT), and multifidus (MF) was measured bilaterally using standard procedures. Participants completed time- and intensity-matched randomized sets of the plank, FC, SC, FH, and SH separated by 5-minute rests. A one-way ANOVA was utilized to compare exercises. The FC/FH load averaged 50.7±1.9 kg, where it was used across equally weighted dumbbells. The FC elicited higher activation bilaterally in the LT, MF, RA, and EO, compared to the FH. The SC/SH single-dumbbell load averaged 25.3±0.95 kg. There was greater activation bilaterally in the LT and MF during the SC compared to the SH. However, on the ipsilateral side of the SC, the RA and EO displayed greater activation compared to the SH, but this was not different on the contralateral side. The FC and SC were characterized by increased core muscle activation bilaterally, with the SC exhibiting unique additions to ipsilateral muscle activation.

Arm cycling ergometry (ACE) leads to a lower maximal oxygen uptake (VO₂max) than cycling which is related to a smaller active muscle mass. This study compared estimates of fat and carbohydrate oxidation (FOx and CHOOx) between progressive exercise protocols varying in stage duration in an attempt to create a standard exercise protocol for determining substrate metabolism using ACE. Four men and seven women (age = 24 ± 9 yr) unfamiliar with ACE completed incremental exercise to determine peak power output and VO₂peak. During two subsequent sessions completed after an overnight fast, they completed progressive ACE using 3- or 5-min stages during which FOx, CHOOx, and blood lactate concentration (BLa) were measured. Results showed no difference (p > 0.05) in FOx, CHOOx, or BLa across stage duration, and there was no difference in maximal fat oxidation (0.16 ± 0.08 vs. 0.13 ± 0.07 g/min, p = 0.07). However, respiratory exchange ratio in response to the 3 min stage duration was significantly lower than the 5 min duration (0.83 ± 0.05 vs. 0.86 ± 0.03, p = 0.04, Cohen's d = 0.76). Results suggest that a 3 min stage duration is preferred to assess substrate metabolism during upper-body exercise in healthy adults.

Substantial health benefits can be derived from walking at a moderate intensity cadence. To help regulate this cadence, three distinct aids exist 1) self-perception; 2) cadence prescription; 3) auditory cues. This study aimed to compare the effectiveness and explore perceptions of these aids to promote moderate intensity walking and effects on affective states, thereby addressing an important research gap. Individualised moderate relative intensity waking cadence was determined for participants (n = 23, M_age = 26.35, SD = 10.11). A convergent mixed-methods design was employed. A within-persons repeated measures design was used to explore the effectiveness of three aids (general guidelines, cadence prescription, and music) on promoting moderate intensity physical activity and positive affective states. Perceptions of these aids were elicited through qualitative interviews and thematic content analysis. Main effects for condition on relative physical activity intensity (η² = .72) and positive affect (η² = .25) were observed. Music evoked significantly higher relative physical activity intensity than other conditions (p values < .01), and higher positive affect compared to the general guidelines condition (p = .038). A significantly greater proportion of participants achieved moderate relative intensity physical activity during the music compared to general guidelines condition (p = .03). Congruently, qualitative findings suggested that participants predominantly perceived music as most effective for promoting a moderate intensity cadence and positive affect. However, individual variability existed in ability to utilise this aid. Implications of the findings for practitioners seeking to promote a moderate intensity cadence and positive affect during walking are discussed.