Skeletal Muscle Mass and Fat Mass Relationships With Physical Fitness Test Performance in Law Enforcement Recruits Before Academy

Assessing skeletal muscle mass and lean body mass: an analysis of the agreement among dual X-ray absorptiometry, anthropometry, and bioelectrical impedance

Introduction

Methods of body composition estimation such as dual-energy X-ray absorptiometry (DXA), anthropometry, and bioimpedance (BIA) are used for the estimation of skeletal muscle mass (SMM) and lean body mass (LBM). No previous studies have examined whether these methods generate comparable results, or whether they are valid by using DXA as the reference. The aims of the present investigation were: (a) to assess the differences between DXA, anthropometry, and BIA in the estimation of SMM and LBM, taking into consideration the impact of sex and hydration status; and (b) to examine the agreement of anthropometry and BIA as compared to DXA for the estimation of SMM and LBM.

Methods

A descriptive cross-sectional design was followed with 262 healthy young adults (159 males and 103 females). LBM and SMM were assessed by anthropometry with the formulas from Lee et al. and Kulkarni et al. for LBM; and Kerr (opt a), Kerr (opt b), Lee et al., Poortmans, Matiegka, Martin et al., Drinkwater and Ross, and Heymsfield et al. for SMM; by BIA with the formula reported by the TANITA MC-780-MA software for LBM and SMM; and DXA with the formula reported by the Hologic Horizon software for LBM, and the conversion by Kim et al. for SMM.

Results

Significant differences were found for both SMM and LBM in kg, and percentages between most methods and formulas for the overall sample (p < 0.001-0.003) and divided by sex (p < 0.001-0.035). Hydration status did not have a significant effect on the differences between methods and formulas (p = 0.058-0.870). Lin's coefficient revealed limited agreement among the majority of formulas and methods (CCC = 0.007-0.880). The Bland-Altman analysis showed significant differences in most methods and formulas, both in the overall sample and divided by sex, when using SMM and LBM with DXA as the reference (p < 0.001-0.030).

Conclusion

There is a lack of agreement between methods and formulas for assessing SMM and LBM. Sex was found to be a significant factor in this analysis. Furthermore, significant differences were observed between most formulas and methods as compared to DXA, except for the equations to estimate SMM with anthropometry by Poortmans.

Agreement and differences between the equations for estimating muscle and bone mass using the anthropometric method in recreational strength trainees

Introduction

The interest in estimating muscle mass (MM) and bone mass (BM) has grown in the sporting arena, and more specifically in recreational strength trainees, leading to the creation of different strategies to assess them. The aims were: 1) to investigate the agreement between different MM and BM formulas, and the muscle-bone index (MBI), and to establish the differences between them, in a healthy young adult population; and 2) to analyze if there are differences between males and females in the comparison of MM, BM and MBI formulas.

Methods

This study followed a descriptive cross-sectional design. A total of 130 adult active recreational strength trainees were evaluated according to the procedures described by the International Society for the Advancement in Kinanthropometry (ISAK). Estimations were made in kilograms of MM and BM by following the equations by different authors.

Results

The results showed significant differences between the values obtained by all the MM and BM formulas in the general sample (p < 0.001), and by the majority of formulas for male and female samples. In the general sample, Lin's coefficient indicated a strong agreement between Kerr, Lee, and Poortmans' MM estimation equations (concordance correlation coefficient (CCC) = 0.96-0.97). However, when stratifying by sex, this agreement persisted only in males (CCC = 0.90-0.94), in contrast with a lack of agreement observed in females (CCC < 0.90). Discrepancies in bone mass agreement were noted both in the general sample (CCC < 0.15) and when stratified by sex (CCC < 0.12).

Conclusions

In general, differences were found between the values reported by the MM and BM formulas in recreational strength trainees, without an agreement between them. Sex was shown to significantly influence the differences found. The practical implications are that when comparing an individual with reference tables, other studies, or if analyzing an individual's evolution, the same estimation equation should be used, as they are not interchangeable.

A Research Note Investigating the Leg Tuck and Plank With Potential Impacts for Occupational Testing

ABSTRACT

Gonzalez, SM, Withrow, KL, Rubin, DA, Lynn, SK, Dawes, JJ, Orr, RM, and Lockie, RG. A research note investigating the leg tuck and plank with potential impacts for occupational testing. J Strength Cond Res 37(10): 2076-2079, 2023-The U.S. Army recently replaced the leg tuck with the plank in their physical ability testing. There has been limited analysis of whether these 2 tests correlate, have any relationships with body composition and strength, or are sex-neutral. Forty-nine civilian college students (28 males, 21 females) were recruited as surrogates for tactical personnel. The following were measured: height, body mass, body fat percentage (BF%), and muscle mass percentage (MM%) measured through bioelectrical impedance analysis, grip strength, leg tuck, and plank. Independent t -tests were calculated to determine between-sex differences for all variables ( p < 0.05). Partial correlations controlling for sex were used to compute relationships between the leg tuck, plank, and other variables. Stepwise regression controlling for sex derived predictive relationships for the leg tuck and plank. Males were taller, had greater body mass, MM%, and were superior in grip strength and the leg tuck; females had greater BF%. There were no significant between-sex differences for the plank. The leg tuck correlated with BF%, MM%, grip strength, and the plank ( r = ±0.333-0.524). In addition to the leg tuck, the plank correlated with BF% ( r = -0.288). The leg tuck was predicted by sex, grip strength, and the plank (adjusted r2 = 0.662). No variables predicted the plank. As there were no between-sex differences and sex was not a plank predictor, it appears this test minimized sex differences on task performance in civilians. However, the leg tuck and plank likely measure different qualities; further research is needed on job task relationships.

Army Combat Fitness Test Relationships to Tactical Foot March Performance in Reserve Officers' Training Corps Cadets

The Army Combat Fitness Test (ACFT), consisting of deadlift, standing power throw, hand release push-up, sprint-drag-carry, leg tuck or plank, and 2-mile run, is the United States Army's new fitness test. The ACFT is designed to measure multiple fitness components required to perform combat tasks. One critical task is the tactical foot march (TFM), where soldiers cover long distances while carrying loads comprised of mission-essential equipment. As the ACFT is meant to predict soldier task performance, determining the relationships between the ACFT and the TFM is important. Data from 29 cadets (♂ = 20, ♀ = 9) from one university Reserve Officers' Training Corps program were analyzed. The ACFT was recorded in raw and scaled scores. The TFM was performed over 6.44 km, with time recorded. Cadets carried a 15.88-kg rucksack, fighting load carrier, 3-L hydration pack, and replica M4 carbine. Independent samples t-tests evaluated ACFT and TFM between-sex differences. Partial correlations, controlling for sex, determined ACFT event and TFM relationships. Male cadets outperformed females in all ACFT tasks (p ≤ 0.039), except the push-up. ACFT total score, leg tuck, 2-mile run, and sprint-drag-carry showed large correlations with the TFM (r = ±0.463-0.531, p ≤ 0.026). Aerobic and anaerobic capacity and upper body/trunk strength were important fitness components for cadet TFM performance.

Body Composition and Fitness Characteristics of Firefighters Participating in a Health and Wellness Program: Relationships and Descriptive Data

This study investigated body composition and fitness test relationships from firefighters participating in a health and wellness program and categorized firefighters according to population norms relative to sex and age. Data from 270 firefighters (men = 258, women = 12) were analyzed, including body composition (body mass index [BMI], body fat percentage [BF%], waist circumference [WC], waist-to-hip ratio) and fitness (sit-and-reach, grip strength, leg press, crunches, push-ups, maximal aerobic capacity [V̇O2max]) tests. Mann-Whitney U-test analysis (p < 0.05) showed that male firefighters had a greater WC, WHR, grip strength and leg press. Female firefighters had a greater BF% and better sit-and-reach. Partial correlations controlling for sex indicated 22/24 correlations between body composition and fitness were significant (r = -0.143--0.640). ~52% of firefighters were overweight, and 25% were Obesity Class I-III. ~76% had an increased risk of cardiovascular disease (CVD) considering BMI and WC. ~22% were fatter than average-to-overfat considering BF%. Most firefighters (73-94%) were good-to-excellent in sit-and-reach, grip strength, and push-ups; average-to-well above average in crunches; average-to-above average in leg press; and had good-to-superior V̇O2max. Although most firefighters had better fitness compared to the general population, many had increased CVD risk. The data highlighted the need for comprehensive approaches to improving firefighter health and decreasing CVD risk.

Health and fitness data for police officers within a health and wellness program: Implications for occupational performance and career longevity

BACKGROUND: Health and wellness programs can be implemented at police departments. Little research has detailed the characteristics of officers within these programs. OBJECTIVE: To analyse the health and fitness data of officers involved in a health and wellness program from 2018–2020, and to profile the officers involved relative to population norms. METHODS: Analysis was conducted on archival data from 633 officers (523 males, 110 females) who participated in a health and wellness program from a large city police department. Data included: body mass; body fat percentage; blood pressure (BP); estimated maximal aerobic capacity; sit-and-reach; push-ups; vertical jump; grip strength; sit-ups; bench press ratio. Data were grouped by year (2018, 2019, 2020), and a univariate ANCOVA with Bonferroni post hoc adjustment determined any significant between-group differences. Individual officer data were also compared to population norms. RESULTS: The 2020 group had higher systolic BP compared to both other groups, and superior sit-and-reach and grip strength compared to the 2018 group (p <  0.05). Compared to population norms across the 3 years, 74–86% of officers had BP elevated above normal levels. Depending on the fitness component measured most officers (69–98%) were categorised as average or better. CONCLUSIONS: There were few differences between the year groups, although the 2020 officers did have superior sit-and-reach and grip strength. The higher systolic BP from the 2020 group may be indicative of the challenges of the year (pandemic, civil unrest). Officers generally had good profiles relative to population norms. The wellness program appeared to benefit the well-being of officers.

Differences in Fitness between Firefighter Trainee Academy Classes and Normative Percentile Rankings

Fire academy training classes may have trainees with a range of different fitness capabilities. Documentation of trainee fitness could indicate the need for flexibility in physical training emphases. Therefore, data from six academy classes (males = 274; females = 31) were analyzed, including: Illinois agility test (IAT), push-ups, pull-ups, leg tucks, multistage fitness test, backwards overhead 4.54 kg medicine ball throw (BOMBT), 10-repetition maximum deadlift, and 18 kg kettlebell farmers carry. A one-way ANOVA, with the Bonferroni post hoc test, calculated between-class fitness differences. Normative fitness test data were produced via percentile ranks. Classes 5 and 6 had the most females (n = 15). Class 1 completed the IAT faster than all classes (p ≤ 0.009). Classes 1 and 4 had a further BOMBT distance than Classes 5 and 6, and Class 3 outperformed Class 6 (p ≤ 0.044). Class 4 completed more leg tucks than Class 5 (p = 0.047). Class 1 had a greater deadlift than Classes 3, 4, and 6, and Class 2 outperformed Classes 3–6 (p ≤ 0.036). Class 3 was slower in the farmers carry compared to all classes (p ≤ 0.002). Percentile rankings showed that most females (48–100%) were in the 0–29% rank. Staff should implement individualized programs where appropriate for trainees as cohort fitness differences exist. Female trainees may need targeted maximal strength and power development.

Fit (and Healthy) for Duty: Blood Lipid Profiles and Physical Fitness Test Relationships from Police Officers in a Health and Wellness Program

This research analyzed archival health and wellness program data (2018: 169 males, 39 females; 2019: 194 males, 43 females) to document police officer lipid profiles, and correlate lipids with fitness. Bloodwork included total cholesterol (TC), low-density lipoproteins (LDL-C), high-density lipoproteins (HDL-C), and triglycerides (TG). Fitness data included maximal aerobic capacity (V·O2max); sit-and-reach; push-ups; vertical jump; grip strength; sit-ups; and relative bench press (RBP). Lipid profiles were compared to national standards. Spearman’s correlations derived relationships between lipids and fitness (p < 0.05). Over 2018−2019, 68−76% of officers had desirable TC (<200 mg/dL) and HDL-C (≥60 mg/dL); 67−72% had desirable TG (<150 mg/dL). 54−62% of officers had LDL-C above desirable (≥100 mg/dL); 13−14% had mildly high TG (150−199 mg/dL); 16−18% had high TG (200−499 mg/dL). In 2018, HDL-C correlated with V·O2max, push-ups, grip strength, and RBP in males, and sit-ups in females. TG correlated with V·O2max (both sexes), sit-ups (males), and grip strength (females). In 2019, TG related to V·O2max, push-ups, vertical jump, sit-ups, and RBP in males. TG and LDL-C related to push-ups, and HDL-C to sit-ups and RBP in females. Relationship strengths were trivial-to-small (ρ = ±0.157 − 0.389). Most officers had good lipid profiles relative to cardiovascular disease risk. Nonetheless, the data highlighted the need for comprehensive approaches to decreasing risk.

How Does Time Spent Working in Custody Influence Health and Fitness Characteristics of Law Enforcement Officers?

This study investigated the influence of time spent working in custody on the health and fitness of law enforcement officers (LEOs). Retrospective analysis was conducted on data from 48 male and 12 female LEOs, divided into groups based upon time spent working custody: LEO ≤ 24 (≤24 months; n = 15); LEO 2547 (25-47 months; n = 24); and LEO 48+ (≥48 months; n = 21). The following were measured: body mass index (BMI); fat mass percentage; waist-to-hip ratio (WHR); resting heart rate (RHR); blood pressure; grip strength; sit-and-reach; push-ups; sit-ups; and YMCA step test recovery heart rate (HR). A univariate ANCOVA (controlling for sex and age) with Bonferroni post hoc determined significant between-group differences. Select assessments were compared to normative data. The LEO 48+ group completed fewer sit-ups than the LEO 2547 group (p = 0.006); there were no other significant between-group differences. Forty-nine LEOs were overweight or obese according to BMI; 52 were fatter than average or above; 27 had a WHR that increased cardiovascular disease risk. Forty-three LEOs had very poor RHR; 52 had elevated blood pressure. Forty-eight LEOs had average-to-very poor step test recovery HR. Irrespective of time spent working in custody, personnel should be physically active to maintain health and fitness and, where possible, engage in formal strength training and conditioning.