Effect of Extreme Volume-Load Differences for a Single Unilateral Exercise During In-Season Resistance Training on Measures of Bilateral Strength, Power, and Speed in Collegiate American Football Players.

ABSTRACT: Crawley, K, Adams, KJ, DeBeliso, M, and Lawrence, MM. Effect of extreme volume-load differences for a single unilateral exercise during in-season resistance training on measures of bilateral strength, power, and speed in collegiate american football players. J Strength Cond Res 38(1): 80-89, 2024-This study examined the impact extreme volume-load differences for a single weekly exercise, when all other exercises' volume loads were similar, would have on American football performance variables after in-season resistance training (RT). Twenty male National Collegiate Athletic Association (NCAA) American footballers (18-23 years, 98.4 ± 19.3 kg) were randomly assigned to an extreme high-volume low-intensity (EHVLI; n = 11) group or a low-volume high-intensity (LVHI; n = 9) group. Subjects performed the same evidence-based RT exercises and volume loads for 8 weeks thrice weekly, with the only differences being once weekly unilateral reverse dumbbell lunge (EHVLI) or unilateral Hatfield safety bar back squat (LVHI) exercises performed with different volume loads. Performance variables were assessed 1 week before (PRE) and after (POST) 8 weeks of RT. A 2-way analysis of variance with repeated measures and the Sidak post hoc test were used ( p < 0.05). Extreme high-volume low-intensity had no significant ( p > 0.05) PRE-to-POST RT changes in muscular strength in 1 repetition maximum (251.8 ± 48.7 to 274.6 ± 61.3 kg) or power in vertical jump (79.2 ± 8.8 to 78.2 ± 10.8 cm). Conversely, LVHI had significant ( p < 0.05) PRE-to-POST RT improvements in strength (249.2 ± 54.4 to 284.1 ± 55.0 kg) and power (72.8 ± 11.4 to 76.3 ± 10.0 cm). Furthermore, LVHI vs. EHVLI displayed significantly greater percentage difference increases from PRE values in muscular power (6.7% ± 7.2 vs. -1.3% ± 6.0, respectively), with no significant differences between groups (LVHI vs. EHVLI) in muscular strength (8.8% ± 3.1 vs. 6.7% ± 8.0, respectively) and 10-yard acceleration (2.2% ± 5.6 vs. 3.2% ± 5.6, respectively). For in-season RT of strength and power in collegiate American football players, all exercises performed should use evidence-based volume loads to optimize adaptations because a single exercise performed with extreme volume load may limit muscular strength and power development.

The Relationship Between Partial and Full Range of Motion Deadlift 1-Repetition Maximum: A Technical Note.

ABSTRACT: Gillingham, B, Bishop, A, Higa, GK, Adams, KJ, and DeBeliso, M. The relationship between partial and full range of motion deadlift 1-repetition maximum: a technical note. J Strength Cond Res 37(4): 909-914, 2023-The full range of motion (FROM) or partial range of motion (PROM) deadlift (DL) are often included in resistance training (RT) programs and are performed by strength athletes in competition. This study examined the relationship between the FROM and PROM 1-repetition maximum (1RM) DL and if the PROM 1RM DL can be estimated by the FROM 1RM DL. Eighteen National Collegiate Athletic Association wrestlers (20.8 ± 1.2 years, 176.0 ± 5.2 cm, 78.9 ± 10.6 kg) performed a warm-up followed by the assessment of the FROM and PROM 1RM DLs. The FROM DLs were executed with a starting position of the bar resting on the lifting platform. Partial range of motion DLs were executed in a power rack with the bar starting position at ≈2.54 cm above the patella. Regression analysis was employed to estimate PROM 1RM DL based on FROM 1RM DL, body height, and mass. A Pearson's correlation coefficient ( r ) was used to compare the PROM 1RM DL with FROM 1RM DL. A dependent t test was used to compare the PROM 1RM DL and FROM 1RM DL scores (α < 0.05). The PROM 1RM DL scores (226.0 ± 40.6 kg) were significantly greater than the FROM 1RM DL scores (191.7 ± 37.2 kg) ( p < 0.05: effect size = 0.92). The PCC between the PROM and FROM 1RM DL was r = 0.85 ( p < 0.05). The regression coefficient for the FROM 1RM DL was significant ( p < 0.05; R = 0.85, R2 = 0.73). The regression coefficients for body mass and height were not significant ( p > 0.05). The PROM and FROM DL may be interchangeable modalities within an RT program, and the PROM 1RM DL can be accurately predicted by the FROM 1RM DL.

Reliability of Trail Walking and Running Tasks Using the Stryd Power Meter.

Footpod monitors are wearable devices attaching to the shoe with the ability to sense oscillations in leg movement; however, few studies provide reliability. The purpose was to provide reliability data for outdoor tasks as measured by the Stryd Power Meter, which is a footpod monitor. Young healthy individuals (N=20, male n=12, female n=8) completed two 5-min self-paced walks along a trail, and two 5-min trail runs. Reliability of the tasks was determined using Coefficient of Variation (CV), Intraclass Correlation (ICC), and 95% confidence intervals (CI). Measures during trail running that returned a CV less than 10%, met the ICC threshold of 0.70, and displayed good to excellent 95% CI included pace, average elapsed power, average elapsed form power, average elapsed leg spring, and vertical oscillation. The only variable during walking to meet these criteria was maximal power (CV=4.02%, ICC=0.968, CI=0.902, 0.989). Running tasks completed on a trail generally return more consistent measures for variables that can be obtained from the Stryd footpod device than walking tasks.

Comparing one repetition maximum and three repetition maximum between conventional and eccentrically loaded deadlifts.

This study determined if an eccentrically loaded deadlift yields a higher 1 repetition maximum (1RM) and 3RM than a conventional deadlift and if the 1RM conventional and eccentrically loaded deadlift can be accurately estimated from the 3RM (3RM = 93% of 1RM). Division 1 football players (n = 15; 20.3 ± 1.9 years; 95.8 ± 18.2 kg; 184.4 ± 6.6 cm) participated. Deadlift 1RM and 3RM were measured in the conventional and eccentrically loaded deadlift. Dependent t-tests showed no significant difference between the 3RM and 1RM conventional deadlift and the 3RM and 1RM eccentrically loaded deadlift (p = 0.30 and p = 0.20, respectively). Pearson correlation between the 1RM conventional deadlift estimate and 1RM conventional deadlift actual was r = 0.91 (p ≤ 0.01); a dependent t-test indicated the 1RM conventional deadlift estimate was significantly less than the 1RM conventional deadlift actual (p = 0.007). Pearson correlation between the 1RM eccentrically loaded deadlift estimate and 1RM eccentrically loaded deadlift actual was r = 0.84 (p ≤ 0.01); a dependent t-test indicated the 1RM eccentrically loaded deadlift estimate was nearly significantly less than the 1RM eccentrically loaded deadlift actual (p = 0.061). Results suggest that conventional and eccentrically loaded deadlifts may be interchangeable within a training program; this may elicit the benefits of using a broader variety of ground-based multijoint compound movements in an athlete's strength and power training. Additionally, because of differences between predicted and actual 1RM scores in the deadlift, strength coaches should prioritize actual 1RM testing of their athletes to optimize deadlift training loads across the RM continuum.

Effects of Supramaximal Anderson Quarter-squats as a Potentiating Stimulus on Discus Performance in Division I Throwers: A Pilot Study.

No study has assessed supramaximal (over 100% 1RM) back squat variations as a potentiating stimulus in collegiate throwers. The purpose of this study was to test the hypothesis that a supramaximal Anderson (bottom-up) quarter squat potentiating stimulus would improve discus throw performance in Division I throwers compared to a dynamic warm-up alone. Nine NCAA division I thrower athletes (age: 20.1±1.4 years; 1RM back squat/body weight: 2.5±0.4 kg) randomly completed two sessions separated by at least 72 hours. One session involved a standardized dynamic warm-up alone (DyWU) followed by three trials of maximal discus throwing. The other session involved a dynamic warm-up with a supramaximal (105% 1RM) Anderson (bottom-up) quarter-squat set of 5 repetitions post activation performance enhancement stimulus (DyWU+PAPE) followed by three trials of maximal discus throwing. A two-way (warm-up strategy x time) ANOVA with repeated measures for each time point was used, with significance set at p< 0.05. There were no significant (p> 0.05) differences between DyWU alone versus DyWU+PAPE stimulus for discus throw distances at either 8 min. (31.7±5.6 vs 30.6±6.5 meters, respectively; d = -0.18), 11 min. (33.4±3.6 vs 31.3±4.7 meters, respectively; d = -0.52), or 14 min. post warm-up (34.1±3.9 vs 32.3±5.3 meters, respectively; d = -0.40). Compared to a dynamic warm-up alone, supramaximal Anderson quarter-squats following a dynamic warm-up had trivial/small to moderate detrimental effects on discus throw performance between 8-14 minutes post stimuli in Division I trained throwers, likely due to excess fatigue/PAPE inhibition.

Resting Blood Pressure in Master Athletes: Immune from Hypertension?

Ageing is associated with decreased physical activity, obesity and increased risk of hypertension (HTN). Master athletes (MA) have either pursued a physically active lifestyle throughout their life or initiated exercise or sport later in life. We assessed resting blood pressure (BP) in male and female World Masters Games (WMG) athletes. This was a cross-sectional, observational study which utilized an online survey to assess the blood pressure (BP) and other physiological parameters. Results: a total of 2793 participants were involved in this study. Key findings included differences between genders with males reporting higher resting SBP (+9.4%, p < 0.001), resting DBP (+5.9%, p < 0.001) and mean arterial pressure (+6.2%, p < 0.001). Significant differences (p < 0.001) were also identified when comparing WMG athletes' resting BP results (genders combined) to the general Australian population with WMG athletes having a lower SBP (p < 0.001, -8.4%) and DBP (p < 0.001, -3.6%). Additionally, 19.9% of males and 49.7% of female WMG participants were normotensive whereas 35.7% of the general Australian population were normotensive. Only 8.1% of the WMG athletes (genders combined) were found to be HTN compared to 17.2% in the general Australian population. These findings reflect a low prevalence of HTN in WMG participants and support our hypothesis of a low prevalence of HTN in an active, but aged cohort of MA.

Heart rate processing algorithms and exercise duration on reliability and validity decisions in biceps-worn Polar Verity Sense and OH1 wearables.

Consumer wearable technology use is widespread and there is a need to validate measures obtained in uncontrolled settings. Because no standard exists for the treatment of heart rate data during exercise, the effect of different approaches on reliability (Coefficient of Variation [CV], Intraclass Correlation Coefficient [ICC]) and validity (Mean Absolute Percent Error [MAPE], Lin's Concordance Correlation Coefficient [CCC)] were determined in the Polar Verity Sense and OH1 during trail running. The Verity Sense met the reliability (CV < 5%, ICC > 0.7) and validity thresholds (MAPE < 5%, CCC > 0.9) in all cases. The OH1 met reliability thresholds in all cases except entire session average (ICC = 0.57). The OH1 met the validity MAPE threshold in all cases (3.3-4.1%), but not CCC (0.6-0.86). Despite various heart rate data processing methods, the approach may not affect reliability and validity interpretation provided adequate data points are obtained. It is also possible that a large volume of data will artificially inflate metrics.

Resilience, Psychological Stress, Physical Activity, and BMI among United States Air National Guardsmen: The COVID-19 Pandemic.

Background: Military service members carry the responsibility to maintain physical and psychological readiness. As such, it is critical for researchers to begin unravelling the widespread impact of the COVID-19 pandemic on service member's mental and physical wellbeing. The aim of this research was to investigate the complex relationships between BMI, physical activity, psychological stress and resilience among United States Air National Guardsmen (USANG), specifically during the pandemic. Methods: An online survey was distributed to USANG members. The survey included measures of resilience (CD-RISC-25), perceived psychological stress (PSS), perceived psychological stress brought on by COVID-19 (COVID-19 PSL), current levels of physical activity (IPAQ-SF), perceived impact on physical activity brought on by COVID-19 (COVID-19 PAL), and BMI. Pearson's correlation coefficients (r) were used to assess correlation significance (α ≤ 0.05), direction, and magnitude. Results: A total of 110 responses met inclusion criteria for data interpretation. A majority reported a decline in physical activity 54.5%, while 60% reported an increase in psychological stress. According to BMI classifications, 60.9% were considered overweight or obese. Seven meaningful (effect size ≥ |2.0|) and statistically significant salient associations were identified resilience-PSS r = -0.38; resilience-COVID-19 PAL r = 0.21; PSS-COVID-19 PSL r = 0.35; PSS-COVID-19 PAL r = -0.23; COVID-19 PSL COVID-19 PAL r = -0.24; IPAQ-SF-BMI r = -0.23; BMI-Covid-19 PAL r = -0.32. Conclusion: Key outcomes suggest resilience is inversely associated with assessed and perceived stress, resilience may influence health-related behaviour which subsequently might aid as a protective factor against psychological stress. Knowledge regarding the relationships between the aforementioned variables may help inform decisions by military leadership regarding future lockdowns.

Prevalence of hyperglycemia in masters athletes.

Background: Ageing is associated with decreased physical activity, obesity and subsequently an increased risk of developing type 2 diabetes mellitus (T2dm). Master athletes (MA) have initiated exercise or sport later in life or pursued a physically active lifestyle for an extended period. Subsequently, MAs have been proposed as a model of successful ageing as this active lifestyle is associated with health benefits including decreased health risk of chronic diseases and a reduction in premature mortality. Given long-term physical activity/exercise has previously been shown to be protective against hyperglycemia, a risk factor for T2dm, it is plausible that MA may have protective benefit against developing hyperglycemia. Therefore, the aim of this study was to investigate the prevalence of hyperglycemia via fasting plasma glucose (FPG) in MAs competing at the World Masters Games (WMG). Methods: This cross-sectional, observational survey utilized an online survey using open-source web-based software was used to investigate MAs physiological and medical-related parameters. Over 28,000 MAs competed in the WMG, of which 8,072 MAs completed the survey. Of these MAs, a total of 486 (males 277, females 209; range 27 to 91 years, mean age 55.1 ± 10.2 years) attained recent pathology results which included FPG which was subsequently analyzed for this study. FPG and other outcome variables were compared between genders and to the Australian and United States general population. Results: Mean FPG for MAs was 5.03 mmol (±1.2, 95% CI [4.9-5.1] mmol) with majority (75.5%) of MAs reporting a normal (<5.5 mmol) FPG, followed by pre-diabetes (20.2%, >5.51 to <5.99 mmol) and abnormal (4.3%, >7.0 mmol). There was no significant difference (P = 0.333) in FPG between genders however, males had a slightly higher (+2.1%) FPG as compared to females (5.08 ± 1.2 mmol (95% CI [4.9-5.22] mmol) versus 4.98 ± 1.1 mmol (95% CI 4.8-5.1 mmol)). The majority of males (71.8%) and females (80.3%) were classified with a normal FPG. With regard to an abnormal FPG level, only 4.0% of males and 4.9% of females were classified abnormal which was suggestive of undiagnosed T2dm. With regard to age by decade, there was no significant difference (P = 0.06-1.00) between age groups and no relationship between the MAs' age and FPG (r = .054, P = 0.24). As a group, MAs had a significantly lower FPG as compared to the Australian (-3.2%, P = 0.005) and United States general populations (-13.9%, P < 0.001). Conclusions: Most, however not all, MAs were found to have normal glycaemia, with only a small percentage indicating a risk of developing T2dm (i.e., impaired fasting glucose) and a smaller percentage identified with an abnormal FPG, suggestive of T2dm. These findings suggest MAs appear to be at low metabolic risk for developing T2dm based upon FPG and the physical activity/exercise they complete as MAs may indeed be protective against hyperglycemia whilst maintaining an active lifestyle.

Tactical Masters Athletes: BMI Index Classifications.

Understanding the nexus between aging, physical activity, and obesity has been a source of ongoing investigation. A considerable amount of research has focused on Masters athletes in this regard, suggesting a beneficial relationship between Masters sport participation and a healthy body mass index (BMI). Some consider Active Duty military personnel as tactical athletes. As such, it is of interest to determine if aging Active Duty military personnel (or Masters Tactical Athletes) might have a similar BMI as other Masters athletes (MA). As such, this investigation examined previously recorded data of Active Duty Enlisted United States Marines (n = 402, male, 46-50 years old). The BMI of the Marines was stratified into categories of: underweight, normal, overweight, and obese. The Marines obesity prevalence was compared to US adult males (40-59 years) as well as male North American MA who competed at the 2009 Sydney World Masters Games. The Marines obesity prevalence was significantly lower than US adult males (p < 0.001) and those MA that competed in softball (p < 0.001); however, it was similar to MA that competed in football, track/field, swimming, and volleyball (p > 0.05). The average Marine BMI = 26.7 kg/m2 was similar to MA who competed in football, swimming, and volley ball (p > 0.05); however, it was higher than MA who competed in track/field (p < 0.05) and lower than MA who played softball (p < 0.05). It should be noted that the average BMI for the Marines and all MA sport categories were classified as being overweight. Within the parameters of this investigation, Tactical MA (i.e., aging US Marines) enjoy a similar beneficial BMI as other North American MA.

The seated medicine ball throw as a test of upper body power in older adults.

Practitioners training the older adult may benefit from a low-cost, easy-to-administer field test of upper body power. This study evaluated validity and reliability of the seated medicine ball throw (SMBT) in older adults. Subjects (n = 33; age 72.4 ± 5.2 years) completed 6 trials of an SMBT in each of 2 testing days and 2 ball masses (1.5 and 3.0 kg). Subjects also completed 6 trials of an explosive push-up (EPU) on a force plate over 2 testing days. Validity was assessed via a Pearson Product-Moment correlation (PPM) between SMBT and EPU maximal vertical force. Reliability of the SMBT was determined using PPMs (r), Intraclass correlation (ICC, R) and Bland-Altman plots (BAPs). For validity, the association between the SMBT and the EPU revealed a PPM of r = 0.641 and r = 0.614 for the 1.5- and 3.0-kg medicine balls, respectively. Test-retest reliability of the 1.5- and 3.0-kg SMBT was r = 0.967 and r = 0.958, respectively. The ICC values of the 1.5- and 3.0-kg SMBT were R = 0.994 and 0.989, respectively. The BAPs revealed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference. Test-retest reliability for the EPU was r = 0.944, R = 0.969. The BAPs showed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference, for both medicine ball throws. In conclusion, for the older adult, the SMBT appears to be highly reliable test of upper body power. Its validity relative to the maximal force exerted during the EPU is modest. The SMBT is an inexpensive, safe, and repeatable measure of upper body power for the older adult.

Effects of Acute Beta-Alanine Ingestion and Immersion-Plus-Exercise on Connectedness to Nature and Perceived Pain.

This double-blinded, placebo-controlled, crossover study examined the effect of induced painful sensation (via acute Beta Alanine (B-ALA) ingestion) on Love and Care of Nature (LCN), heart rate (HR), rating of perceived exertion (RPE), and McGill Pain Questionnaire (MPQ) during outdoor exercise. Twenty participants volunteered on consecutive days to complete a 0.8 km (0.5 mi) up-hill hike after consuming either B-ALA (6.4 g) or placebo. Immediately after consumption participants answered LCN, RPE, and MPQ questionnaires, immersed in a natural environment for 45 min, and then completed a hike as quickly as possible without running. No difference in HR (p = 0.846), or RPE (p = 0.606) were observed between treatments. Total MPQ scores increased with consumption of B-ALA (p = 0.001). An increased LCN score was observed following exercise regardless of condition (p = 0.035). The results demonstrate that acute B-ALA supplementation is effective in increasing perceived pain sensations. The results also demonstrate an increase in LCN in the presence of increased perceptions of pain sensations during exercise.

Effect of functional isometric squats on vertical jump in trained and untrained men.

Functional isometrics (FIs) combine dynamic and isometric muscle actions and may hyperstimulate the nervous system leading to an enhanced postactivation potentiation (PAP) and improved subsequent performance. The purpose of this study was to investigate the impact of an FI squat on the countermovement vertical jump (CMVJ) in resistance trained and untrained men. Thirteen trained men (age: 22.8 +/- 3.2 years, mass: 90.0 +/- 16.3 kg, and height: 178.9 +/- 7.1 cm) and 8 untrained men (age: 28.5 +/- 5.9 years, mass: 101.5 +/- 23.0 kg, and height: 177.0 +/- 4.8 cm) participated. On separate days, subjects performed CMVJs after 2 different warm-up conditions. The warm-up conditions consisted of either 5 minutes of low-intensity cycling or 5 minutes of low-intensity cycling plus a 3-second FI squat with 150% of their 1 repetition maximum (1RM). A 2 x 3 repeated-measures analysis of variance with Bonferroni post hoc revealed that when comparing the 2 warm-up conditions in the trained subjects, a significant increase (p < 0.05) in CMVJ occurred at 4 minutes (2.4 cm, +5.1%) post-FI squat. This increase was maintained when subjects were retested at 5 minutes post (2.6 cm, + 5.5%). No significant difference in CMVJ was detected in the untrained group (p = 0.49). Results support the addition of an FI squat performed at 150% of 1RM to a low-intensity cycling warm-up to enhance PAP in resistance trained but not in untrained men as measured by CMVJ. Practically, adding functional isometrics to a warm-up scheme may significantly enhance acute, short-term power output in resistance trained men.

Physiological and psychophysical comparison between a lifting task with identical weight but different coupling factors.

The objective of the revised NIOSH (National Institute for Occupational Safety and Health) lifting equation is to prevent or reduce lifting-related injuries. The coupling component of the equation relates to quality of the grip (i.e., hand-to-object interface) and can be rated good, fair, or poor. Good coupling is theorized to reduce lifting stress, whereas poor coupling is theorized to increase lifting stress. This study compared the physiological and psychophysical stress between a lifting task with identical weight but different coupling factors. Subjects (n = 21; 26 +/- 6 years; 177.8 +/- 7.8 cm; 73.9 +/- 10.7 kg) transferred a milk crate or bag of dog food each weighing 12.5 kg back and forth from the floor to a table for 2, paced, 5-minute work bouts. Steady-state metabolic data were used to compare the lifting tasks. Results showed significantly higher oxygen consumption, caloric cost, heart rate, and rating of perceived exertion during the lifting task using the milk crate vs. the bag of dog food (p < 0.05). No difference in respiratory exchange ratio was observed (p > 0.05). In conclusion, a significantly higher metabolic cost and perceived exertion was observed when subjects performed a paced two-handed lifting task with good coupling factors than when using an object with poor coupling factors. When lifting stress is measured by metabolic cost and perceived exertion, these results are in contrast to expectations that a poor quality grip (i.e., poor coupling) would increase stress of a lifting task. Results of this study may help the work-place practitioner make decisions related to the use of the revised NIOSH lifting equation in the design and pacing of lifting-related tasks. Improved decision making may benefit productivity and enhance injury prevention in the workplace.

Examining Grit-like Qualities in National Football League Quarterbacks.

In order to excel in the National Football League (NFL) it would seem reasonable to assume an athlete has grit which consists of the constructs of consistency of interest and perseverance of effort. Grit-like qualities such as endurance, urgency and intensity, self-confidence, need for encouragement, and self-criticality may be of particular value for the athlete playing the Quarterback (QB) position. The purpose of the study was to assess the 5 grit-like constructs of endurance, urgency and intensity, self-confidence, need for encouragement, and self-criticality among NFL QBs. The Flippen ProfileTM assessment was administered to 29 NFL QBs and the 5 grit-like constructs were recorded. Each of the 5 grit-like constructs were scored on a scale of 0-100, where high scores were considered desirable for endurance, urgency and intensity, and self-confidence, while lower scores were considered as desirable for need for encouragement, and self-criticality. The scores for each of the 5 grit-like constructs were then partitioned by three categories of QB years played: 1-2 (n=8), 3-7 (n=13), and ≥8 (n=8) years. Four key findings emerged following the analysis: the NFL QBs scored favorably on all of the 5 grit-like constructs independent of years played, QBs with ≥8 years' experience scored the most favorably for endurance and the need for encouragement, QBs with 1-2 years' experience scored the most favorably for self-criticality. These results may provide coaches and athletes aspiring to play QB in the NFL with benchmarks regarding the 5 grit-like constructs that are associated with successful NFL QBs.

A Comparison of United States Marine Corps Physical Fitness Test and Combat Fitness Test Results.

The United States Marines Corps (USMC) have installed a Physical Fitness Test (PFT) to measure physical fitness levels and a Combat Fitness Test (CFT) to assess a Marine's functional fitness as it relates to the demands of combat operations. The PFT involves three events; pull-ups/push-ups (PU), two-minute abdominal crunches/sit-ups (AC), and a timed three-mile run (RUN). The CFT also involves three events; Movement to Contact (MTC), two-minute Ammunition Lift (AL), and Maneuver-Under-Fire (MANUF). It is of interest to determine if the PFT and CFT are both necessary. As such, the purpose of this study was to determine the degree of relationships between PFT (PU, AC, RUN, and total) and CFT (MTC, AL, MANUF, and total) scores of active duty Marines. The PFT and CFT scores from 19,678 active duty enlisted USMC males (age 22.5±1.3 years, height 1.77±0.07 m, body mass 79.4±10.3 kg) were analyzed. Pearson correlation coefficients (r) were calculated between the PFT and CFT total scores as well as individual events. The PFT mean±sd scores were as follows: PU=18.0±5.0 (pull-ups), AC=111.2±9.0 (repetitions), RUN=1377.0±131.4 sec, PFT total=249.6±29.6. The CFT mean±sd scores were as follows: MTC=172.5±16.3 sec, AL=113.2±10.4 repetitions, MANUF=138.3±17.2 sec, CFT total=271.6±25.6. Moderate significant (p<0.01) correlations were found between: the PFT total and MTC (r=-0.47), PFT total and MANUF (r=-0.42), PFT total and CFT total (r=0.50), RUN and MTC (r=0.46), RUN and CFT total (r=-0.43), & PU and CFT total (r=0.41). Other correlations between variables yielded "no to low" association but were also significant due to the large sample size. Within the parameters of this study, PFT and CFT event scores demonstrated no to moderate correlations suggesting that different fitness characteristics are being assessed and supports the need for both the PFT and CFT assessments.

Concurrent heart rate validity of wearable technology devices during trail running.

Validation of heart rate responses in wearable technology devices is generally composed of laboratory-based protocols that are steady state in nature and as a result, high accuracy measures are returned. However, there is a need to understand device validity in applied settings that include varied intensities of exercise. The purpose was to determine concurrent heart rate validity during trail running. Twenty-one healthy participants volunteered (female n = 10, [mean (SD)]: age = 31 [11] years, height = 173.0 [7] cm, mass = 75.6 [13] kg). Participants were outfitted with wearable technology devices (Garmin Fenix 5 wristwatch, Jabra Elite Sport earbuds, Motiv ring, Scosche Rhythm+ forearm band, Suunto Spartan Sport watch with accompanying chest strap) and completed a self-paced 3.22 km trail run while concurrently wearing a criterion heart rate strap (Polar H7 heart rate monitor). The trail runs were out-and-back with the first 1.61 km in an uphill direction, and the 1.61 return being downhill in nature. Validity was determined through three methods: Mean Absolute Percent Error (MAPE), Bland-Altman Limits of Agreement (LOA), and Lin's Concordance Coefficient (rC). Validity measures overall are as follows: Garmin Fenix 5 (MAPE = 13%, LOA = -32 to 162, rC = 0.32), Jabra Elite Sport (MAPE = 23%, LOA = -464 to 503, rC = 0.38), Motiv ring (MAPE = 16%, LOA = -52 to 96, rC = 0.29), Scosche Rhythm+ (MAPE = 6%, LOA = -114 to 120, rC = 0.79), Suunto Spartan Sport (MAPE = 2%, LOA = -62 to 61, rC = 0.96). All photoplethysmography-based (PPG) devices displayed poor heart rate agreement during variable intensity trail running. Until technological advances occur in PPG-based devices allowing for acceptable agreement, heart rate in outdoor environments should be obtained using an ECG-based chest strap that can be connected to a wristwatch or other comparable receiver.

Does cardiac morphology predict plasma brain natriuretic Peptide levels in adolescent athletes?

OBJECTIVE: The purpose of this study was to establish the relationship of plasma levels of brain natriuretic peptide (BNP) to physiologic parameters and cardiac morphologic characteristics in a population of young athletes. Our hypothesis is that physiologic and cardiac morphologic characteristics do not predict BNP levels in adolescent athletes. DESIGN: Observational study. SETTING: Outpatient hospital. PARTICIPANTS: Thirty healthy male adolescent high school football players (16.0 +/- 1.1 years). INTERVENTIONS: Physical exam, electrocardiography, plasma BNP measurement by rapid fluorescent immunoassay, and limited echocardiography. MAIN OUTCOME MEASURES: Null hypothesis-physiologic parameters and cardiac morphology do not predict plasma BNP levels in healthy adolescent football players. Significance level set at P < 0.05. RESULTS: Plasma BNP for this population was 11.9 +/- 10.2 pg/mL. There was no correlation between BNP and mean arterial pressure (r = -0.09, P = 0.64), body mass index (r = 0.11, P = 0.57), interventricular septal thickness (r = -0.15, P = 0.44), left ventricular (LV) wall thickness (r = 0.00, P = 0.99), relative wall thickness (r = -0.04, P = 0.84), LV mass (r = 0.05, P = 0.79), or LV mass index (r = 0.11, P = 0.55). CONCLUSIONS: Plasma BNP levels in healthy adolescent athletes have no correlation to body mass index or LV mass, even when corrected for body surface area.

Cardiovascular and Psychophysical Response to Repetitive Lifting Tasks in Women.

BACKGROUND: Understanding the cardiovascular and psychophysical demands of repetitive lifting tasks is important in job design strategies. This study determined the cardiovascular (oxygen consumption (VO2) and heart rate (HR) and psychophysical response to repetitive lifting tasks in women. METHODS: Ten female (age 27 ± 5 yrs) participants transferred 11.4, 15.9, and 20.5 kg weights back and forth from a rung 40.6 cm high to a rung 156.2 cm high. Rungs were 195.6 cm apart horizontally. Three, 10 minute bouts (1 = 11.4 kg; 2 = 15.9 kg; 3 = 20.5 kg) were performed at 6 lifts per minute. Cardiovascular and psychophysical (rating of perceived exertion, RPE) parameters were monitored throughout the bouts. VO2max and HRmax were determined via a maximal treadmill test. RESULTS: VO2, HR, and RPE were significantly different between each work bout (p < 0.01), with each outcome variable increasing as load increased. VO2max and HRmax equaled 46.5 ± 7.5 mL·kg-1·min-1 and 191 ± 11 bpm, respectively. Work at 11.4 kg was performed at 38% VO2max and 63% HRmax; at 15.9 kg at 41% VO2max and 72% HRmax; and at 20.5 kg at 49% VO2max and 81% HRmax. RPE at 11.4, 15.9, and 20.5 kgs were: 8.4 ± 1.6, 11.4 ± 1.9, and 15.0 ± 2.2. CONCLUSION: During these repetitive lifting tasks, metabolic cost and perceived exertion increased with weight lifted; average work intensity ranged from 63 to 81% of HRmax and 38 to 49% of VO2max. Results have important implications in relation to job pacing and design, and worksite health promotion strategies aimed at reducing work place injury.