Effects of CrossFit training on lipid profiles, body composition and physical fitness in overweight men

Somatotype and bioelectrical impedance vector analysis of Italian CrossFit® practitioners

Objectives

CrossFit® is a high-intensity sport characterized by various workouts that require strength, speed, endurance, or agility, impacting participants' body composition. This observational study aimed to determine the morphological (anthropometrical and bioelectrical) profile of CrossFit® athletes and to compare them with other athletic populations.

Methods

Anthropometrical measurements and bioelectrical vector analysis (classic and specific approaches) were performed on 145 CrossFit® practitioners (107 men aged 30.7 ± 8.4 years and 38 women aged 28.1 ± 6.7 years). Each participant's relative somatotype was calculated and compared between sexes and with a Spanish CrossFit® athletes' group. Resistance-reactance graphs and Hotelling's T2 test were applied to characterize the sample, compare them with an athletes' reference population, and identify differences between somatotype groups.

Results

The most represented somatotype in both groups was the balanced mesomorph (male 3.5-5.2 - 1.7 and female 4.4-4.5 - 1.8). Compared with Spanish CrossFit® athletes, significant differences were denoted for men but not women (SAD = 2.3). The bioelectrical graphs indicated that the distribution of CrossFit® athletes is quite heterogeneous and within average values for the athlete's reference. The mesomorphic and endomorphic components were associated with a higher phase angle.

Conclusions

CrossFit® practitioners predominantly present a mesomorphic component and show a body type like other power athletes, although with less pronounced characteristics. The somatotype may influence the vector's position in the RXc graphs. This study provided the bioelectrical tolerance ellipses for CrossFit® practitioners in classic and specific approaches for the first time.

Non-Traditional Physical Education Classes Improve High School Students' Movement Competency and Fitness: A Mixed-Methods Program Evaluation Study

Non-traditional physical education (PE) programs may facilitate functional movement patterns and develop fitness and work capacity to facilitate long-term physical activity. This program evaluation study compared changes in body composition, movement competency, work capacity, and fitness for high school students in CrossFit or weight training PE; both classes were hypothesized to improve each area, with greater improvements in the CrossFit class. Students participated in 57 min classes 4 days per week for 9 months. Measures including body composition, movement competencies (squat, lunge, push-up, pull-up, hinge, and brace), work capacity (two CrossFit workouts), and fitness (air squats, push-ups, inverted row, plank hold, horizontal and vertical jumps, 5 rep max back squat and press, 500 m bike, and 12 min run) were taken at baseline, midpoint, and post-test. Focus groups to assess students' experiences and outcomes were conducted at post-test. Students significantly improved in movement competencies (ps = 0.034 to <0.001), work capacity (ps < 0.001), and all fitness tests (ps = 0.036 to <0.001). The CrossFit class was only superior on the 500 m bike. Four themes were identified from the focus groups: (1) increased self-confidence, (2) health improvements, (3) newfound community, and (4) translational sports improvements. Future research should examine changes using an experimental design.

Physiological effects of regular CrossFit® training and the impact of the COVID-19 pandemic—A systematic review

CrossFit® is a functional fitness training program known for its day-to-day varying “Workouts of the Day” (WOD). In accordance with the ‘CrossFit® Level 1 Training Guide’, regular CrossFit® training sessions consist of Warm-up, Mobility, Skill/Power training, WOD, and Cool-down. Despite the fast-growing and widespread popularity, data on the practical implementation of the training program based on scientific evidence are rare. Therefore, the purpose of this study is to systematically review the existing literature on the physiological effects of regular CrossFit® training in full extent instead of stand-alone WODs and to examine the impact of the COVID-19 pandemic on the training behavior of CrossFit® athletes. A systematic search was conducted following the PRISMA guidelines in April 2022 and updated in July 2022 using the following databases: PubMed, SPORTDiscus, Scopus, and Web of Science. Using the keyword “CrossFit”, 1,264 records were found. Based on the eligibility criteria, 12 studies are included and separated by topics: acute-short term physiological response (n = 8), and impact of the COVID-19 pandemic (n = 4). The results show that studies of regular training sessions were rarely conducted and contradicted the existing knowledge of the physiological demands [e.g., heart rate (HR)] of CrossFit®. In detail, included studies demonstrate that training sessions last 30–60 min and provide a progressive increase in cardiovascular load up to maximal effort activity (&gt;90% HRmax), differing from stand-alone WODs exclusively at high-intensity. Also, scarce research exists on COVID-19-pandemic-induced effects on training behavior, and studies are of moderate to low quality. There is still a lack of comprehensive analyses on the acute physiological effects of regular training sessions and the consequences of the COVID-19 pandemic in the scientific literature. Moreover, the inconsistent terminology used in CrossFit® research complicates generalized conclusions. Therefore, future research on the training methodology of CrossFit® needs to overcome terminological inequalities and examine scientifically the implementation of the concept by considering regular training sessions under practical settings.

Effect of High-Intensity Strength and Endurance Training in the Form of Small Circuits on Changes in Lipid Levels in Men Aged 35–40 Years

Background: Blood lipid profiles consist of total cholesterol (TC) and its fractions, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), non-high-density lipoprotein cholesterol (non-HDL), and triglycerides (TG). For several decades, studies have examined the effects of various factors on lipid status and its association with the risk of developing arteriosclerosis and cardiovascular disease. The beneficial effects of increased physical activity on cardiovascular health have been demonstrated by appropriate modulation of lipid profiles. For individuals with low physical activity, the literature recommends engaging in various forms of training that can improve physical fitness and resting lipid status. The aim of the study was to examine whether a specific original training program improves lipid profiles to the levels recommended for the male population. Methods: The study involved two equal (n = 15) groups of men (experimental and control groups, aged 35–40 years). The experimental group performed 60-min training sessions for 8 weeks (3 times a week) including a set of strength and endurance exercises. Before and after the training program, blood was drawn from both groups for serum determination of TC, HDL, LDL non-HDL, and TG, and a battery of four field physical performance tests was administered. Results: Statistically significant decreases (TC by 19.3%, TG by 23.7%, LDL by 15%), a non-significant decrease (10% for non-HDL), and no change for HDL were found in the experimental group. Control group showed a statistically significant decrease, by 7.4% for TC. The results confirm the effectiveness of the proposed training in improving health indices. Conclusions: The 8-week training program met the health-related fitness paradigm recommended for physical activity in men aged 35–40 years. After the completion of the program, all the participants expressed their satisfaction from participating in a health-promoting experiment.

Incidence, severity and perceived susceptibility of COVID-19 in the UK CrossFit population

BACKGROUND

Contemporary literature indicates that a higher body mass index (BMI) serves as a risk factor for metabolic disease and is also correlated with greater disease severity. Subsequently, it has been linked to increased COVID-19 severity. The purpose of the study was to investigate whether regular CrossFit™ participation was associated with lower BMI, decreased COVID-19 severity and susceptibility.

METHODS

A cross-sectional study was conducted on 1806 CrossFit™ (CF) participants. Participants were asked about their age (yrs), sex (male vs. female), ethnic group, body height (cm) and weight (kg). Body mass index (BMI, kg/m2) was computed and consistent with WHO (2018) criteria. Participants self-reported their training history, health and lifestyle history, nutritional customs, present training status and suspected levels of exposure to COVID-19. Once submitted the collected data were coded, cleaned and analysed.

RESULTS

The final model comprised of 1806 CF individuals from an online survey response rate of 2086. The participants age ranged from 18 to 65+ yrs. Self-reported mean body mass index (BMI: kg/m2) reported that < 1% were underweight, 41% were healthy, 46% overweight, 10% class I obese, 2% class II obese, and < 1% class III obese. A Kruskal-Wallis H test compared gender and self-reported probability of being infected with COVID-19 with significant differences between subgroups (x2 (4, N = 1739) = 10.86, p = 0.03). Analysis of BMI and perceived severity of COVID-19 revealed a difference however not, significant (x2 (4, N = 1739) = 9.46, p = 0.051). Results on BMI and perceived probability of COVID-19 infection revealed no significant difference (x2 (4, N = 1739) = 2.68, p = 0.61). A separate analysis on BMI and perceived COVID-19 susceptibility revealed no significant difference (x2 (4, N = 1740) = 6.02, p = 0.20).

CONCLUSIONS

The purpose of the study was to establish whether habitual CrossFit™ participation is associated with reduced BMI, and to further investigate whether habitual participation impacted perceptions of disease. Results of the study indicate that self-reported CrossFit™ participation during the first UK lockdown, measured in minutes of exercise was indicative of a lower BMI. This has been associated with greater host immunity to disease. A history of CrossFit™ participation was not shown to impact perceptions of disease. However, our sample population reported few changes to habitual exercise during lockdown which may be due to the 'community' and increased adherence associated with CrossFit™.