Nathaniel Bodell

Background and Objectives: Wearable heart rate monitors are widely used for performance monitoring and safety, yet their validity during resistance training is limited. This study evaluated the accuracy and reliability of wrist-worn Garmin Instinct 2 monitors during deadlift exercise across multiple intensities, using the Polar H10 chest strap as the criterion measure. Methods: Twenty-one recreationally active adults (four women, 17 men, 0 identified otherwise) completed deadlift sets at low (RPE 3–4) and moderate-to-high (RPE 6–8) intensities while heart rate (HR) was recorded using four Garmin Instinct 2 devices placed on the inner and outer wrists of each forearm and one Polar H10 chest strap. Inter-device reliability was examined using the Intraclass Correlation Coefficient (ICC [1,2]) and the Coefficient of Variation (CV). Validity was assessed via mean absolute percentage error (MAPE) and Lin’s Concordance Correlation Coefficient (CCC). Results: Outer wrist placement met the threshold for reliability and one measure of validity during low intensity exercise (average HR CV = 2.7%, ICC = 0.88, MAPE = 8.5% [left forearm], 9.5% [right forearm], CCC = 0.55 [left forearm], 0.52 [right forearm]; maximal HR CV = 2.9%, ICC = 0.88, MAPE = 3.2% [left forearm], 7.7% [right forearm], CCC = 0.61 [left forearm], 0.60 [right forearm]). No validity thresholds were met during moderate-to-high intensity exercise (average HR MAPE = 15.9% [left forearm], 15.9% [right forearm], CCC = 0.57 [left forearm], 0.60 [right forearm]; maximal HR MAPE = 30.1% [left forearm], 13.5% [right forearm], CCC = 0.53 [left forearm], 0.55 [right forearm]). Inner wrist placement did not meet any reliability or validity threshold for any condition. Conclusions: Outer wrist placement of the Garmin Instinct 2 achieved acceptable MAPE under low-intensity loading, but measures of accuracy appeared to decline with increased intensity. Inner wrist placement failed to return any conditions in which reliability or validity thresholds were met for either average or maximal heart rate. For training or occupational settings requiring precise HR monitoring, chest strap monitors or bicep-worn sensors are still recommended.

The purpose of this pilot study was to associate the history of extracurricular activity practice with the performance on the Functional Movement Screen Test, and to correlate different directions of the Y Balance Test with the performance on the Functional Movement Screen Test, as well as the weekly time spent on physical activities. Six women (age: 25.67 ± 4.68 years; height: 1.61 ± 0.06 m; total body mass: 65.47 ± 10.31 kg; body mass index: 25.06 ± 3.94) voluntarily participated in the present study. Each participant visited the laboratory on a single occasion, during which anthropometric measurements and movement pattern data (Functional Movement Screen Test and Y Balance Test) were collected, along with their past and current history of physical activity practice. Regarding the associations between the Functional Movement Screen Test and the history of extracurricular physical activity practice, no significant association was observed (p>0.05). Similarly, there were no significant correlations (p > 0.05) between the Functional Movement Screen Test and any of the Y Balance Test directions, nor between the weekly time spent on physical activities and any of the Y Balance Test directions. With respect to physical education in childhood, the study underscored its relevance for maintaining an active lifestyle in adulthood. It also highlighted the importance of school physical education and the role of the physical education teacher in encouraging physical activity among children. There are still open questions and a need for more studies and research on the topic, especially concerning improvements in current class programs to better engage students in physical activity and consequently promote a more active future.

The present study proposed to compare the acute effect of stretching (SE) before resistance exercise (RE) sessions using different intervals (30 vs. 60 vs. 120 seconds) on maximal repetition performance of recreationally trained adults. Twenty men (age: 29.5 ± 7.05 years; height: 82.92 ± 8.47 kg; weight: 1.78 ± 0.07 cm; body mass index: 26.03 ± 1.55 m2kg-1) recreationally trained in RE (≥ 6 months) completed 4 interventions: 1) RE with 60-second intervals (RE60"), 2) SE plus RE with 30-second intervals (SE+RE30"), 3) SE plus RE with 60-second intervals (SE+RE60"), and 4) SE plus RE with 120-second intervals (SE+RE120"). The RE consisted of three sets until muscle failure of the following exercises: bench press, bench press 35°, decline bench press, biceps curl, and biceps curl 45° at 80% of 10RM. The SE involved two sets of 30-second static SE for chest and biceps separated by a 40-second passive interval. The maximum number of repetitions performed until muscle failure was counted at the end of each set. The results of this study show a progressive reduction in maximum repetitions performance between sets and exercises in tested protocols with and without SE. Significant reductions were presented for the SE+RE30" protocol compared to the RE60" and SE+RE120" protocols. The present study suggests that 60" intervals between sets are necessary to avoid a significant reduction in maximum repetitions performance. Keywords: Neuromuscular performance, strength, strength training

Background: Increased fat intake leads to a greater risk of atherosclerosis due to the increase in circulating triglycerides (TG), which damages the endothelial lining. An oral fat tolerance test (OFTT) is usually employed to evaluate postprandial lipid metabolism. However, there has yet to be a standardized procedure for doing an OFTT. This investigation assists in the determination of a standardized, reliable, and valid OFTT. Methods: All participants (n=20) were free of any known cardiovascular or metabolic disease. Participants were allotted 20 minutes to complete the OFTT. Baseline and subsequent blood analyses postfeeding were collected at 1, 2, 3, and 4 hours. One of the three OFTT loads of varying fat concentrations was administered to each participant in a randomized crossover design, containing fat loads of 150 g, 100 g, and 50 g of fat. A single-measure consistency intraclass correlation coefficient was used to determine significance (r>0.75). Results: The test-retest reliability of the OFTT loads (150 g, 100 g, and 50 g) were all significant (p<0.001), with ICC at 0.745, 0.923, and 0.715, respectively. Face Validity was confirmed upon repeat analysis. Conclusions: The 100 g OFTT load was the most reliable and valid measure for observing TG elevation. It is proposed that the 100 g load would be a reliable tool for further research investigation and eventual use for clinical purposes.

International Journal of Exercise Science 15(4): 834-845, 2022. Indoor sport rock climbing has been increasing in popularity both recreationally and competitively. Despite this increase in popularity, the physiological responses to sport climbing as an exercise to specific muscle groups are not well defined. The purpose of this study was to quantify the change in handgrip strength over a 30-minute bout of continuous climbing, specifically in intermediate-level sport climbers. Ten intermediate rock climbers (age = 27 ± 2 years; climbing experience: 7.3 ± 1.5 years) completed baseline handgrip strength and forearm girth measurements. Each participant ascended one of two 5.9 difficulty routes as many times as possible in 30 minutes. After each ascent, heart rate was obtained, and handgrip strength and forearm girth were measured. Data were analyzed using repeated-measures ANOVA with significance set at a < 0.05. Dominant arm handgrip strength decreased by 22%, and non-dominant handgrip strength reduced by 23%. Dominant and non-dominant forearm girth increased by 4.5% and 4.4%, respectively. Weak but significant negative correlations were observed between handgrip strength and forearm girth in dominant (r = -0.311, p = 0.001) and non-dominant limbs (r = -.491, p = 0.001). These results indicate a relationship between increased forearm girth and decreases in muscular strength. Since handgrip strength decreases substantially during a 30-min climb in intermediate rock climbers, this population would be advised to carefully monitor recovery time between bouts.

International Journal of Exercise Science 11(6): 281-289, 2018. Female participation is growing in trail running races. The purpose was to evaluate sex and age differences in top finishers of a trail running half marathon. Velocity differences between males (M) and females (F) were determined for the top 10 finishers of the Moab Trail Half Marathon from 2012 - 2015 across age, and by finishing place. Differences between age category and between sexes were determined through ANOVA with significance accepted at P < 0.05. A significant difference for running velocity was present between sexes at each age category (20-29 yr F = 2.9±0.3, M = 3.4±0.4 m·sec-1; 30-39 yr F = 2.8±0.3, M = 3.3±0.3; 40-49 yr F = 2.7±0.3, M = 3.0±0.5; 50-59 yr F = 2.3±0.2, M = 2.8±0.3; 60-69 yr F = 1.6±0.3, M = 2.2±0.4; P < 0.0001). Sex difference in trail running velocity was consistent (~13%) among all age categories with exception of the oldest group (33%, P = 0.0001). There were significantly greater female finishers in every age category (20 - 29 yr F = 107±18, M = 56±1;, 30 - 39 yr F = 150±34, M = 84±21; 40 - 49 yr F = 112±17, M = 64±16; P < 0.01) until 50 - 59 yr (F = 48±13, M = 41±14; P = 0.50). These data indicate that the widening gap in sex differences observed in road races are ameliorated in a trail running environment that has a larger number of female participants.