Are extreme conditioning programmes effective and safe? A narrative review of high-intensity functional training methods research paradigms and findings

Qualified fitness trainers practice scientifically based judgement in prescribing exercise programs

Fitness trainers are widely in demand by both commercial fitness centres and individual people. They serve members in one-to-one personal training (PT) or group training (GX) in commercial fitness centres. However, the services provided by fitness trainers have not been consistent across the industry. This service inconsistency has led to an increased doubt about professionalism in conducting safe and correct exercise for the public. No studies have evaluated how fitness trainers make decisions when they curate exercise programs for members. This research utilized a qualitative semi-structured interview method to collect data from 16 fitness trainers in Greater Kuala Lumpur, Malaysia. Inverview data was verbatim transcribed and analyzed using a theory-driven analysis. The study investigated fitness training professional decision-making processes when they design and precribe fitness execise programming to clients. Using Cognitive Continuum Theory (CCT) as a lens to explore the decision-making processes revealed a dichotomy of decision-making processes for curating personal training and group training. Feedback mechanism in the implementation of personal training was proven to be more personalized than group training. There are four themes in decision-making processed discovered to be impreative characteristics for fitness trainers. The application of CCT allowed further understanding of the implementation of exercise programs for PT and GX training when fitness trainers modified exercise programs.

Occupational Health-Related Problems among Portuguese Fitness Instructors

BACKGROUND

The fitness sector has experienced significant expansion, with fitness instructors (FIs) playing a pivotal role. Given the demands of their profession, understanding their health profile is crucial. This study's purpose is to explore the prevalence of fitness instructors' occupational health-related problems.

METHODS

A questionnaire covering sociodemographic, occupational, and health-related items was administered. Statistical analyses, including Mann-Whitney U and chi-square tests, Spearman's rho correlations, and logistic regressions, were conducted.

RESULTS

Fifty-nine FIs reported occupational health-related problems, with the majority occurring during instruction (66.1%), being muscular (32.2%), and knee (15.3%), the most common type and localization. Significant statistical differences were observed between injured and non-injured FIs, including sex (p = 0.012), years as an FI (p = 0.001), weekly days worked (p = 0.039), and daily hours worked (p = 0.013). Weak negative (-0.284 - -0.362) statistically significant correlations were found between health problems; weight; height; main activity; and FIs in the workplace. Logistic regressions identified significant models showing that having a sport/physical exercise background and practicing it regularly were less likely to report bursitis (OR 0.018; p = 0.020) and hip injuries (OR 0.026; p = 0.037).

CONCLUSIONS

Approximately one-third of FIs reported occupational-related health problems, predominantly musculoskeletal injuries. Sociodemographic, personal, and occupational factors appear to influence the prevalence of these health problems.

Effects of functional training on muscle strength, jumping, and functional movement screen in wushu athletes: A systematic review

This study aims to analyse the effects of functional training on muscle strength, jumping, and functional movement screen in wushu athletes.

METHODS

This study followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A systematic search of electronic databases was also conducted, including EBSCOhost, Scopus, PubMed, Web of Science, CNKI, Google Scholar, and Wanfang. The Physiotherapy Evidence Database (PEDro) scale was an effective indicator to evaluate the quality of studies included in the systematic review.

RESULTS

This systematic review included 474 participants aged 8-24 years old. The intervention period for most studies was 12 weeks. Among the included studies, 6 focused on muscle strength, 4 on jumping performance, and 11 on functional movement screen.

CONCLUSION

These articles have been analysed, and the positive impact of functional training interventions on muscle strength, jumping, and functional movement screen of wushu athletes has been verified.

Effects of Crossfit® and street running practice on anthropometric, lipids parameters, cardiorespiratory fitness and sleep quality

BACKGROUND

Street running (SR) and CrossFit® (CF) have different characteristics ranging from aerobic training to high intensity. This study aimed to describe the subject's physical training, anthropometric and lipid parameters, cardiorespiratory fitness and sleep quality and duration.

METHODS

Cross-sectional, study, that collected personal data, Pittsburgh Sleep Quality Index (PSQI), anthropometric assessment, cardiorespiratory fitness, and lipid profile. The subjects were separated in CF group (CFG) and SR group (SRG).

RESULTS

The SRG training frequency was lower (P=0.006), had better maximum oxygen consumption (V̇O2max) levels (P<0.001). 59.3% of the SRG had excellent V̇O2max. Cardiorespiratory fitness (49.97 mL/kg/min; P=0.001) and Body Mass Index (BMI) were positively related in SR (P=0.031). An inverse correlation was found between V̇O2max and body fat percentage (BF%) (SRG: P=0.001; CFG: P=0.013). Sleep duration is strongly and inversely associated with PSQI. There was a correlation between total cholesterol (TC) and high-density lipoprotein cholesterol (P=0.020), TC and triglycerides (TGs) (P=0.029) and levels of TGs and BMI (P=0.008) in SRG. In the CFG group, there was a correlation of TC between TGs levels (P=0.025), light-density lipoprotein cholesterol (P<0.001) and BMI (P=0.050).

CONCLUSIONS

The SR have a higher V̇O2max although they train less than the CF practitioners regardless of factors such as BF%, gender and age.

Renal physiology and kidney injury during intense (CrossFit®) exercise

BACKGROUND

High-intensity training (HIT) programmes are popularly associated with improvements in exercise efficiency and body composition, although, at extremes, have been accompanied by concerns of secondary rhabdomyolysis and severe acute kidney injury (AKI). Beyond the anecdotal, robust literature on the physiological impact of HIT on renal function is currently limited.

AIMS

To investigate the acute impact of high-intensity (CrossFit®) training on renal function, and to evaluate the incidence of AKI by Risk, Injury, Failure, Loss, End-stage renal disease (RIFLE) criteria following CrossFit® training.

METHODS

Clinical and biochemical parameters were measured in 22 healthy adults before and after two CrossFit® workouts: 'Fran' (12 men, 10 women) and 'Macho Man' (9 men, 4 women).

RESULTS

Serum creatinine increased by 16 ± 10 μmol/L following Fran and 18 ± 12 μmol/L following Macho Man (P < 0.05). Cystatin C did not change significantly following Fran and increased by 0.06 ± 0.06 mg/L (P < 0.05) following Macho Man. AKI, as defined by RIFLE 'Risk' criteria, was observed in 5/22 (23%) participants following Fran and 5/13 (38%) participants following Macho Man. Urinary albumin/creatinine ratio rose by 18.7 ± 18.3 and 5.2 ± 6.0 mg/mmol following Fran and Macho Man respectively off non-albuminuric baselines (P < 0.05).

CONCLUSIONS

Intense (CrossFit®) exercise is associated with significant metabolic demands and alterations in parameters of renal physiology and function. The observed rise in both conventional and novel biomarkers of renal function following the workout Macho Man specifically might indicate a degree of transient subclinical functional impairment with CrossFit®-type training.

Risk Factors for Musculoskeletal Injury in CrossFit: A Systematic Review

The objective of this systematic review was to identify potential risk factors for injury in CrossFit participants. Embase, Medline, Web of Science, Cochrane, CINAHL, Google Scholar, and SportDiscuss databases were all searched up to June 2021. Cohort studies that investigated risk factors for CrossFit injuries requiring medical attention or leading to time loss in sports were included. A best-evidence synthesis was performed combining all the outcomes from prospective cohort studies. From 9,452 publications identified, we included three prospective cohort studies from which two had a low risk of bias and one a high risk of bias. The studies examined 691 participants of whom 172 sustained an injury. There was limited evidence that switching between prescribed and scaled loads during training is associated with increased injury risk and that increased duration of participation is a protective factor for injury. This could mean that novice CrossFit athletes and those increasing their training load should have closer supervision by CrossFit coaches. These risk factors should be considered when developing preventive interventions.

Epidemiology of Exertional Rhabdomyolysis in the United States: Analysis of NEISS Database 2000 to 2019

OBJECTIVE

There have been numerous case series of exertional rhabdomyolysis (ER) but no comprehensive studies investigating the incidence of ER in the civilian athletic population in the United States (US).

METHODS

A retrospective review of patients with ER presenting to emergency departments in the US over a 20-year period between 2000 and 2019 was performed using the National Electronic Injury Surveillance System (NEISS) database.

RESULTS

The national estimate of hospital visits in the US for ER during the 20-year period was 40,654 (0.66 per 100,000 population). There was a 10-fold increase in the incidence of ER from the first to the second decade. The odds of ER were 3.77 (95% CI 3.67-3.86, P < .0001) times higher for males (31,921, 78.5%, 1.06 per 100,000) than females (8,733, 21.5%, 0.28 per 100,000) and 3.82 (95% CI 3.71-3.93, P < .0001) higher in African Americans (33.6, 0.93 per 100,000) than white patients (53%, 0.24 per 100,000). American football (3,064, 7.5%) was responsible for 43.9% of the sports-induced ER cases. The majority (67.3%) of ER cases occurred between the ages of 16 and 35 years old. The majority of patients required hospitalization (26,550, 65.3%).

CONCLUSIONS

The number of ER cases presenting to emergency departments in the US increased from 2000-2009 to 2010-2019. Young males and African Americans are at highest risk of ER. There was a high rate of hospitalization.

Biomechanical analysis of wheelchair athletes with paraplegia during cross-training exercises

CONTEXT

Extreme conditioning programs (ECPs), such as CrossFit^®, are a relatively new method of fitness with rapid growth in individuals with paraplegia. However, it is unknown if wheelchair users are at an additional risk of musculoskeletal injury during these exercises. Biomechanical characterization is necessary to determine the safety and efficacy of ECPs as an exercise modality for wheelchair users with paraplegia.

OBJECTIVE

To characterize the three-dimensional (3-D) thorax and upper extremity joint kinematics of paraplegic wheelchair athletes during exercises commonly prescribed as part of ECPs.

DESIGN

Observational study.

PARTICIPANTS

Three male wheelchair athletes, average age of 37.1 ± 4.6 years, with spinal cord injury levels of T8, L2, and T10, with varying exercise experience.

METHODS

3-D movement was acquired using motion capture during the performance of four exercises: battle ropes, sled pull, overhead press, and sledgehammer swing. A custom upper extremity inverse kinematics model was applied to compute 3-D joint angles.

OUTCOME MEASURES

3-D peak thorax, glenohumeral, elbow, and wrist joint angles and ranges of motion (ROM), Visual Analog Scale (VAS), and Borg Scale of Perceived Exertion.

RESULTS

Large joint motions were required for the exercises, at times demanding extreme shoulder and/or wrist flexion and extension, abduction, and external rotation, which are concerning for injury risk in wheelchair users. Participants, however, were able to perform the exercises pain free.

CONCLUSION

These quantitative findings highlight that wheelchair athletes may be exposed to potentially injurious positions during common ECP exercises. These findings provide insight that may lead to improved clinical guidelines for prescription and training of exercise regimens, particularly involving ECPs, for wheelchair users.

Upper Extremity Injuries in CrossFit Athletes-a Review of the Current Literature

PURPOSE OF REVIEW

Cross-discipline fitness, or CrossFit, has exploded in popularity during the last two decades. During this time, there have been a high volume of patients presenting to clinicians with a wide range of associated injuries. Given the high intensity, high repetition, and competitive nature of CrossFit training and competition, athletes are vulnerable to injury, particularly upper extremity injury. The rate of injury to the shoulder, elbow, and wrist in CrossFit is higher when compared to traditional weight-training and more comparable to elite-level gymnastics and Olympic-style lifting. Due to the growing popularity of CrossFit-style exercise and the relatively high rate of injury among its participants, clinicians are likely to encounter these athletes. The purpose of this review is to familiarize clinicians with CrossFit and the associated injuries they will likely encounter.

RECENT FINDINGS

The medical literature focusing on CrossFit has demonstrated exponential growth, with the first article published in 2012 and 59 articles published in 2020. Although the body of literature is growing, there are no high-level studies focusing on CrossFit. The literature mainly consists of level IV and V studies, primarily consisting of case reports and case series. Recent studies have proven that CrossFit athletes are vulnerable to high rates of upper extremity injury and a few studies have identified risk factors for injury. Future high-level research is required to study modifiable risk factors, diagnostic criteria, and treatment options for these high-risk athletes in order to improve the safety of their sport. The CrossFit body of research is limited to level IV and V studies; however, the literature is clear, CrossFit athletes face a high rate of upper extremity injury. For this reason, clinicians must be familiar with CrossFit and its associated pathology. The goal of this review is to familiarize clinicians with CrossFit and the associated pathologies they will likely encounter.

Effects of Training Loads on Stress Tolerance and Mucosal Immunity in High-Intensity Functional Fitness Athletes

Purpose: This study aimed to analyze the effects of training load on stress tolerance (ST) and secretory immunoglobulin A (SIgA) in male and female high-intensity functional fitness (HIFF) athletes during two different 10 and consecutive weekly training volume loads [higher (week 1) and lower volume (week 2)]. Methods: 14 athletes [7 males: 29.3 (±5.8) years; 86.3 (±8.2) kg and 176.8 (±3.8) cm and 7 females: 32.7 (±4.4) years; 60.0 (±6.7) kg and 162.5 (±5.9) cm] participated. The ST, assessed by Daily Analysis of Life Demand in Athletes questionnaire (DALDA) and Saliva sampling were performed in four time-points (pre (T1) and post (T2) week 1; pre (T3) and post (T4) week 2). Results: Female athletes showed a decrease in ST (symptoms of stress) from 15 T1 to T3 [F_(3,36) = 7.184, p˂ 0.001, ηp² = 0.374], without difference in male athletes (p > .05). There is a significant difference of SIgA concentration [F_(3.36) = 3.551; p = .024; ηp² = 0.228], with a significant decrease in female athletes group in T2 compared to T1 (p = .013) and T4 (p = .023). In addition, the different training volume loads did not impact mucosal immunity in male athletes (p > .05). Conclusion: The current findings suggest that higher HIFF volume results in decreased ST and SIgA concentration in female 20 athletes and a subsequent decrease in training volume loads contributed to restoring these variables.

Purchasing behavior and use of digital sports offers by CrossFit® and weightlifting athletes during the first SARS-CoV-2 lockdown in Germany

BACKGROUND

To combat the spread of SARS-CoV-2, CrossFit® training centers, and fitness studios were closed during the first lockdown in Germany from mid-March until June 2020, and as a result, CrossFit® (CFA) or weightlifting athletes (WLA) faced a major challenge for the first time. Therefore, this study aimed to investigate the impact of the first lockdown on the training behavior and to analyze the way the athletes dealt with the new situation. In detail, we focus on habits of purchase and examine the acceptance of digital sports offers between CFA and WLA in response to the restrictions of the nationwide lockdown.

METHODS

An online survey was used to characterize the purchasing behavior and use of digital sports offers of CFA and WLA. In total, 484 volunteers (192 women, 290 men, 2 diverse) responded to the online questionary, allowing us to identify changes in training behavior and differences between the sports disciplines.

RESULTS

Our data shows both CFA and WLA purchase new equipment for a home gym and the use of digital sports increased significantly across all age groups. A comparison during the lockdown even showed that within the CFA, one group (n = 142) reported losing 5 kg or more of body mass, while the value of the WLA remained constant. On the one hand, the results indicate that despite the restrictions during the lockdown, CFA were may able to enhance health aspects by improving their body composition. On the other hand, this study shows that the training habits of both groups of athletes have changed significantly with the use of digital sports offers.

CONCLUSIONS

We suppose that the great openness and the expansion of online sports offers during the first lockdown may change the sports industry in the future.

Impact of a short-term low calorie diet alone or with interval exercise on quality of life and oxidized phospholipids in obese females

The objective of this study was to test if a low-calorie diet plus interval exercise (LCD+INT) reduced oxidized and non-oxidized phospholipids in relation to improved weight-related quality of life (QoL) to a greater extent than an energy-deficit matched LCD in obese females. Subjects (age: 47.2 ± 2.6 years, body mass index: 37.5 ± 1.3 kg/m²) were randomized to a 13-day LCD (n = 12; mixed meals of ∼1200 kcal/day) or LCD+INT (n = 13; 12 sessions of 60 min/day alternating 3 min at 50% and 90% peak heart rate plus an additional 350 kcal shake fed after exercise to match energy availability between groups). Weight-related QoL (Laval Questionnaire) as well as oxidized (POVPC, HOOA-PC, HPETE-PC, HETE-PC, PEIPC, KOOA-PC) and non-oxidized (PAPC and lysoPC) phospholipids were assessed pre- and post-intervention. Fitness (VO₂peak), body composition (BodPod), and clinical bloods were also tested. LCD+INT significantly increased VO₂peak (mL/kg/min, P = 0.03) compared to LCD despite similar fat loss, blood glucose, insulin sensitivity, and inflammatory responses. LCD+INT had significantly greater increases in QoL sexual life domain (P = 0.05) and tended to have a greater increase in the emotions domain (P = 0.09) and total score (P = 0.10) compared to LCD. There were no significant differences between treatments for changes in phospholipids despite LCD+INT increasing measured oxidized and non-oxidized phospholipids while LCD decreased POVPC, HOOA-PC, and PEIPC as well as non-oxidized PAPC and lysoPC. Interestingly, the rise in PEIPC correlated with elevated VO₂peak (mL/kg/min r = 0.42, P = 0.05). Decreased caloric intake was, however, linked to a decrease in PAPC (r = 0.53, P = 0.01), lysoPC (r = 0.52, P = 0.02), POVPC (r = 0.43, P = 0.05), and HPETE-PC (r = 0.43, P = 0.05). The decrease in HETE-PC also correlated with increases in the QoL domains symptoms (r = -0.46, P = 0.04), hygiene/clothing (r = -0.53, P = 0.01), emotions (r = -0.53, P = 0.01), social interactions (r = -0.49, P = 0.02), and total score (r = -0.52, P = 0.02). In conclusion, although LCD and LCD+INT improved weight related QoL over 13 days in females with obesity, LCD+INT tended to improve sexual life, emotions as well as total QoL score more than LCD. These data suggest caloric restriction and fitness may act through different mechanisms to support QoL.

Time-course effects of functional fitness sessions performed at different intensities on the metabolic, hormonal, and BDNF responses in trained men

Background

To investigate the time-course effects of a self-regulated training session (performed at an rating perceived exertion of 6/10), all-out session, and a control session on the metabolic, hormonal, and brain derived neurotrophic factor (BDNF) responses in Functional-Fitness (FFT) participants.

Methods

In a randomized, crossover fashion, eight healthy males (age 28.1 ± 5.4 years old; body mass 77.2 ± 4.4 kg; VO_2max: 52.6 ± 4.6 mL.(kg.min)⁻¹; 2000 m rowing test 7.35 ± 0.18 min; 1RM back squat 135.6 ± 21.9 kg) performed a FFT session under two different conditions: all-out, or with the intensity controlled to elicit an rating perceived exertion (RPE) of 6 in the Borg 10-point scale (RPE6). A control session (no exercise) was also completed. Metabolic (lactate and creatine kinase), hormonal (testosterone and cortisol), and BDNF responses were assessed pre, post-0 h, 1 h, 2 h and 24 h after the sessions.

Results

Creatine kinase concentrations were significantly higher (p ≤ 0.05) after 24 h for both training sessions. Total and free testosterone concentrations were lower post-2 h for all-out when compared to the RPE6 session (p ≤ 0.05). Serum cortisol concentration increased post-0 h (p = 0.011) for RPE6 and post-0 h (p = 0.003) and post-1 h (p = 0.030) for all-out session when comparing to baseline concentrations. BDNF was significantly higher (p = 0.002) post-0 h only for the all-out session when compared to baseline. A positive correlation between blood lactate concentrations and BDNF (r = 0.51; p = 0.01) was found for both effort interventions.

Conclusions

A single FFT session when performed in all-out format acutely increases the concentrations of serum BDNF. However, physiological stress markers show that the all-out session requires a longer recovery period when compared to the RPE6 protocol. These findings can be helpful to coaches and practitioners design FFT session.

Injury in CrossFit®: A Systematic Review of Epidemiology and Risk Factors

OBJECTIVE

To review the characteristics of the injuries among CrossFit® practitioners, including prevalence and incidence, nature, location, and risk factors.

METHODS

PubMed/MEDLINE, EMBASE, Web of Science, Scopus, and SPORTDiscus databases were searched from inception through August 2020, and English-language articles reporting on CrossFit®-related injuries were included. Data including sample (sex, age, and demographics) and injuries' characteristics (prevalence, incidence rate, nature, location, percentage of injuries requiring surgery and risk factors) were extracted.

RESULTS

Overall, twenty-five studies involving a total of 12,079 CrossFit® practitioners met the inclusion criteria. The mean prevalence of injuries among the included studies was 35.3%, with an incidence rate varying between 0.2 and 18.9 per 1000 hours of training. The most injured areas were shoulder (26%), spine (24%), and knee (18%). Among the studies that reported the injuries requiring surgery, the mean percentage was 8.7%. Regarding the risk factors associated with injuries, older age, male sex, a greater body mass index, the existence of previous injuries, the lack of coach supervision, the experience on CrossFit® and the participation in competitions were reported by the studies.

CONCLUSIONS

CrossFit® training has an injury incidence rate similar to weightlifting and powerlifting. Findings from the studies suggest that the most affected areas are shoulder, spine, and knee. The limited quality of the studies prevents us from drawing solid conclusions about injury risk factors.

Krill-Oil-Dependent Increases in HS-Omega-3 Index, Plasma Choline and Antioxidant Capacity in Well-Conditioned Power Training Athletes

There is evidence that both omega-3 polyunsaturated fatty acids (n-3 PUFAs) and choline can influence sports performance, but information establishing their combined effects when given in the form of krill oil during power training protocols is missing. The purpose of this study was therefore to characterize n-3 PUFA and choline profiles after a one-hour period of high-intensity physical workout after 12 weeks of supplementation. Thirty-five healthy power training athletes received either 2.5 g/day of Neptune krill oil^TM (550 mg EPA/DHA and 150 mg choline) or olive oil (placebo) in a randomized double-blind design. After 12 weeks, only the krill oil group showed a significant HS-Omega-3 Index increase from 4.82 to 6.77% and a reduction in the ARA/EPA ratio (from 50.72 to 13.61%) (p < 0.001). The krill oil group showed significantly higher recovery of choline concentrations relative to the placebo group from the end of the first to the beginning of the second exercise test (p = 0.04) and an 8% decrease in total antioxidant capacity post-exercise versus 21% in the placebo group (p = 0.35). In conclusion, krill oil can be used as a nutritional strategy for increasing the HS-Omega-3 Index, recover choline concentrations and address oxidative stress after intense power trainings.

Exercise training complementary to specialised early intervention in patients with first-episode psychosis: a feasibility randomised trial

Background

The aim of this study was to examine feasibility of trial processes and group-based, structured exercise training in patients with first-episode psychosis.

Methods

Twenty-five patients with first-episode psychosis took part in a two-arm randomised feasibility trial. They were individually randomised (1:1) via a computer-generated randomisation sequence and allocated to either an exercise intervention group (INT) or a control group (CON). Patients allocated to INT completed a physical exercise training programme at moderate-to-vigorous intensity, 1 h three times weekly for 8 weeks. CON patients were encouraged to continue their usual level of activity and were offered the training programme after 8 weeks. Primary outcomes included screening rate, recruitment rate, retention rate, attendance and adverse events. Secondary outcomes included heart rate response during training, cardiovascular health (VO_2max, resting heart rate, blood pressure), body composition (muscle mass, fat percentage), muscle strength (sit-to-stand, grip strength, jump height) and balance.

Results

Recruitment lasted 6 weeks and 86 out of 324 patients (27%) were screened, 71 of whom (83%) were deemed eligible. Twenty-five (35%) accepted inclusion (mean age 25.5; mean body mass index 25.1) and were subsequently randomised (INT = 13, CON = 12). Retention of patients was 76% and 52% at the 8-week and 16-week follow-up, respectively. Attendance was 43% (min. 9%, max. 96%). No significant changes were observed between groups in secondary physiological outcome measures.

Conclusions

Feasibility was challenged by limited recruitment and retention rates, suggesting that modifications are required if a large-scale randomised controlled trial is to be conducted. Recommendations for modifications are presented and discussed.

Trial registration

Clinicaltrials.gov, NCT03409393. Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00900-5.

Local Muscle Endurance and Strength Had Strong Relationship with CrossFit® Open 2020 in Amateur Athletes

This study analyzed the relationship between anthropometric measures, cardiorespiratory capacity, strength, power, and local muscle endurance with performance in the CrossFit^® Open 2020. For this, 17 volunteers (6 women) (29.0 ± 7.2 years) completed, on separate weeks, tests for body composition (dual-energy X-ray absorptiometry), maximal oxygen consumption (2 km row test), muscle strength (one repetition maximum (1 RM) back and front squat, isometric peak torque), muscle power (1 RM snatch and clean and jerk) and muscle endurance (Tibana test), which were compared with performance during the CrossFit^® Open 2020. Specific tests of localized muscular endurance and muscle strength had the strongest relationship with performance in the CrossFit^® Open 2020. On the other hand, the percentage of fat and cardiorespiratory capacity were not significantly correlated with CrossFit^® Open 2020 workout performance. Coaches and practitioners should therefore utilize these findings to assess physical fitness and organize the distribution of the training session based on less developed physical needs, in order to ensure an appropriate physiological adaptation for a given competition.

Injuries in functional fitness: an updated systematic review

INTRODUCTION

This study aimed to analyze injuries of functional fitness participants through a systematic review.

EVIDENCE ACQUISITION

A systematic search of the literature was conducted in CINAHL, EMBASE, PEDro, PubMed, SCOPUS, SPORTDiscus, and Web of Science, supplemented by searching in the grey literature, from 2017 to November 2020. This systematic review followed the PRISMA guidelines and was documented in the PROSPERO registry (CRD42020201259). Two reviewers independently extracted data including methodological (age, sex, time of practice, location, period, time frame, and completion rate) and injury (definition, diagnosis, prevalence, incidence, severity, mechanism, type, location, risk factors, and treatment) variables, as well as assessing study quality and risk of bias.

EVIDENCE SYNTHESIS

Twenty-six studies were included (10967, range 6-3049, participants). Injury was defined fairly differently across studies. The majority of studies used a retrospective study design and the main variables reported were prevalence, body location, and associated factors of injuries. The mean prevalence of musculoskeletal injuries was 32.8%, ranging from 2.4 to 60.6%, and the injury incidence per 1000 hours ranged from 0.21 to 67 36. The most affected body location in the studies was the shoulder, followed by lumbar spine, and knee. Muscle, joint, and ligament/tendon injuries were the most frequently reported. The majority of studies were of moderate methodological quality. All studies were considered as high risk of bias.

CONCLUSIONS

This review broadened the scope of 75 previous reviews on injuries in functional fitness. There have been few investigations regarding severity, mechanism, and treatment of injuries, so further research is warranted.

Acute leucocyte, muscle damage, and stress marker responses to high-intensity functional training

BACKGROUND

High-intensity functional training (HIFT) has become more popular, and the number of practitioners has increased; however, it remains unclear whether perturbations in the immune parameters occur, even after one single bout. Our aim was to examine acute leucocyte, muscle damage, and stress marker responses following a single 'Cindy' workout session, and compare the results between novice and experienced participants.

MATERIAL AND METHODS

Twenty-three HIFT practitioners (age 31.0 ± 1.0 years) completed the 'Cindy' workout. They were categorized as novice (3-8 months of experience; n = 10) and experienced (≥18 months; n = 13). White blood cell (WBC) count, plasma creatine kinase (CK) activity, blood cortisol level, and lactate concentration were measured. Blood analysis was performed before (pre-ex), immediately after (post-ex), 30 min after (post-30 min), and 24 h after (post-24 h) a single 'Cindy' workout session.

RESULTS

WBC count was higher post-ex (6.8 to 11.8x103/μL) and returned to baseline values within post-30 min (p<0.01). Neutrophil (3.3 to 4.5x103/μL) and lymphocyte levels (2.8 to 5.9x103/μL) were higher post-ex and returned to baseline values after post-24 h, yet lymphocytopoenia (2.2x103/μL) was observed at post-30 min (p<0.01). CK increased post-ex (174.9 to 226.7 U.L-1) and remained elevated post-24 h. Cortisol (14.7 to 17.0 μg/dL) and lactate (1.9 to 13.5 mmol.l-1) responses increased post-ex, but only the lactate level was reduced at post-30 min (p<0.01). The experienced participants had higher WBC, lymphocyte, and cortisol concentrations post-ex than the novice ones (p<0.01).

CONCLUSIONS

A single HIFT session elicited significant acute perturbations in WBC count, stress markers, and muscle tissue, which is like other similar regimens. Importantly, the experienced participants showed greater lymphocyte and cortisol responses than the novice ones.

Acute and Chronic Catabolic Responses to

Given the wide variety of conditioning program trainings employed, the present study compared the catabolic effects induced by CrossFit^® and resistance training in moderately trained subjects. Twenty males joined either the CrossFit^® group (n = 10; 30 min/day of “workout of the day”) or the resistance training (RT) group (n = 10; 30 min/day of resistance exercises) thrice a week, for 8 weeks. Salivary levels of cortisol, interleukin 1-beta (IL-1β), and uric acid were assessed via enzyme-linked immunosorbent assays before (PRE) and 30-min after (POST) SESSION 1 and SESSION 24. Variables’ percentual changes were computed as (POST-PRE)/PRE*100 in each session (Δ%). CrossFit^® acutely increased cortisol levels in both sessions, with a significant decrease in Δ%cortisol from SESSION 1 to 24. In the RT group, cortisol values decreased in both sessions, only acutely. A significant decrease in IL-1β levels was registered acutely in both groups, in both sessions, whereas Δ%IL-1β was not different between the two groups. While uric acid levels increased in both groups acutely, a chronic downregulation of Δ%uric acid, from SESSION 1 to 24, was appreciated for the RT group only. Overall, CrossFit^® appeared to induce more intense effects than the RT program as to the investigated catabolic responses.

Injury Surveillance During Competitive Functional Fitness Racing Events

High-intensity functional training (HIFT) is an exercise training modality that has grown considerably in popularity over the last decade. More recently, competitive functional fitness racing events have emerged from HIFT, and aim to test athletes' proficiency across a variety of movements, skills, and energy systems. Whilst the injury risk associated with HIFT has been shown to be low and comparable to other forms of recreational fitness activities, the injury risk associated with competitive functional fitness racing events is currently unknown. A prospective cohort design was used to record medical-attention injuries during two competitive functional fitness racing events, involving 1085 competitors. A total of 26 injuries were recorded over the two competitions, resulting in an injury incidence rate of 36 per 1000 competition hours (90% confidence limits [CL]: 26-50) and injury prevalence of 2.4% (90% CL: 1.6-3.2%). The shoulder (n=4) and hand (n=4) were the most commonly injured body locations. The incidence rate in male athletes was likely higher than female athletes (Rate Ratio [RR]: 1.87, 90% CL: 0.95-3.69). The injury incidence rate associated with competitive functional fitness racing events is higher than for HIFT training activities, though the injury prevalence is relatively low in comparison to other sporting activities. Further research is required to understand the burden of these injuries, and identify appropriate injury prevention strategies for this emerging sport.

“Cross” modalities: are the AMRAP, RFT and EMOM models applicable to health?

Abstract Currently, training models based on the maximum number of repetitions/rounds or on the execution of a proposed task in the shortest possible time have been gaining ground among Physical Education professionals. However, in our opinion, these models have significant drawbacks that oppose their use in the health context. Thus, we provide an analysis of the problems related to the control and magnitude of the training load (volume and intensity), distribution, duration, and characteristics of the recovery intervals and, of course, the intra-session density. This analysis was made without having measured each of these proposals directly. It is based on the reflection of the dynamics of the efforts made and potential fatigue generated. We hope to be able to verify and provide accurate and reliable data that may support and confirm the hypothesis generated through this analysis.

Time-Course of Changes in Physiological, Psychological, and Performance Markers following a Functional-Fitness Competition

Functional Fitness Training (FFT) programs are characterized by utilizing a high volume of training and using a variety of high intensity exercises. While FFT are growing in the number of practitioners and popularity, the relationship between physiological biomarkers and subjective scales in the specific context of FFT has not yet been evaluated in the literature. The purpose of the present study was to monitor the time-course response of cytokines (IL-10 and 1L-1β), immune variables (C-reactive protein -CRP and immunoglobulin A-IgA), hormonal milieu (cortisol-C, total testosterone-TT, free testosterone-FT and testosterone/cortisol-T/C ratio), creatine kinase-CK, muscle performance (countermovement jump height) and perceived well-being (WB) following a functional fitness competition. Nine amateur male athletes (age 27.1 ± 4.1 years; training experience 2.2 ± 1.3 years) completed five workouts over three consecutive days of FFT-competition. All variables were measured before, 24 h, 48 h, and 72 h following the last day of competition. The FFT-competition induced a decrease in IL10/IL1β ratio approximately 5% after 24h, 21% after 48h and 31% after 72h. Delta T/C ratio remained unchanged during the post-competition period. IgA displayed a significant increase 24h and 72h post FFT-competition. The WB status score was higher 72h after the FFT-competition as compared with pre-competition. The present findings suggest that FFT-competition induces transient changes in some inflammatory and hormonal biomarkers, and perceived well-being seems to be efficient to detect changes in muscle performance.

Is Perceived Exertion a Useful Indicator of the Metabolic and Cardiovascular Responses to a Metabolic Conditioning Session of Functional Fitness?

The purpose of this study was to assess whether the self-regulation of training intensity based on rating of perceived exertion (RPE) is a reliable method to control the intensity during metabolic conditioning sessions of functional fitness. In addition, the relationship between RPE and the changes in heart rate, number of repetitions, and lactate responses was also analyzed. Eight male participants (age 28.1 ± 5.4 years; body mass 77.2 ± 4.4 kg; VO₂ max: 52.6 ± 4.6 mL·(kg·min)⁻¹ completed two sessions (five to seven days apart), in a randomized order, under different conditions, as follows: (1) all-out (ALL), or (2) self-regulation of intensity based on an RPE of six (hard) on the Borg CR-10 scale (RPE6). The rating of perceived exertion, lactate (LAC), and heart rate (HR) response were measured before, during, and immediately after the sessions. The RPE and LAC during the all-out sessions were higher (p < 0.0005) than the RPE6 session for all of the analyzed time points during the session. There was no difference in the HR area under the curve for the all-out and RPE6 sessions. The average number of repetitions performed was lower (p ≤ 0.009) for the RPE6 session (190.5 ± 12.5 repetitions) when compared to the all-out session (214.4 ± 18.6 repetitions). There was a significant correlation between the RPE and LAC (p = 0.005; r = 0.66; large) and number of repetitions during the session (p = 0.026; r = 0.55; large). No correlation was observed between the RPE and HR (p = 0.147; r = 0.380). These results indicate that the self-regulation of intensity of effort based on the RPE may be a useful tool to control the exercise intensity during a metabolic conditioning session of functional fitness.

The impact of exercise training complementary to early intervention in patients with first-episode psychosis: a qualitative sub-study from a randomized controlled feasibility trial

BACKGROUND

Burgeoning evidence suggests that exercise improves physical and mental health in people with schizophrenia. However, little is known about the feasibility and acceptability of high-intensity training in patients with first-episode psychosis. This qualitative study explored motivation, social interaction and experiences of participants and instructors in relation to an eight-week moderate to high intensity exercise training programme in a clinical trial including patients with first-episode psychosis.

METHODS

The study used a combination of method, source and investigator triangulation. Data were collected by means of semi-structured individual interviews with participants at baseline (n = 16) and at follow-up (n = 9), as well as by means of participant observations during the programme (8 sessions × 1.5 h, 12 h in total) and focus group discussions with participants (n = 3) and instructors (n = 4), respectively, after the programme. Data were analysed using thematic analysis as described by Braun and Clarke.

RESULTS

Three main themes and ten subthemes emerged during the analysis: 1) motivation and expectations for enrolment (subthemes: routines and structure, social obligation, goal setting and self-worth); 2) new demands and opportunities (subthemes: practicalities of the training, an understanding exercise setting, and alone and together); and 3) looking ahead - reflections on impact (subthemes: restored sleep and circadian rhythm, energy and sense of achievement, changed everyday life, and hope of finding a new path). Findings suggest that the programme was appealing to, and appreciated by, the participants because of its potential to create an equally challenging and caring non-clinical environment.

CONCLUSIONS

This study indicates that supervised, group-based, moderate to high intensity exercise training complementary to early intervention in psychosis is acceptable. Specifically, the intervention appeared to provide patients an opportunity to integrate the notion of being a young individual along with being a patient with a psychiatric diagnosis, thus supporting and promoting recovery.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03409393. Registered January 24, 2018.

Combining supervised run interval training or moderate-intensity continuous training with the diabetes prevention program on clinical outcomes

PURPOSE

The present study was designed to evaluate the 16 weeks diabetes prevention program (DPP) combined with instructed run sprint interval training (INT) or moderate-intensity continuous training (MICT) on glycemic control, body composition, fitness, exercise adherence, and perceived exercise enjoyment in sedentary, adults with prediabetes.

METHODS

Participants completed three weekly supervised sessions of INT (4-10 bouts of 30 s maximal sprints followed by a 4 min active recovery) or MICT (30-60 min at 45-55% HRR) exercise coupled with the DPP for 16 weeks. At baseline, 8 and 16 weeks, participants completed fitness and clinical assessments as well as questionnaires to assess group and time differences.

RESULTS

Twenty-nine study participants (INT n = 17, MICT n = 12) were randomized, however, significantly (p = 0.024) more participants withdrew from the INT (n = 11) than MICT (n = 4) treatment. There was no significant difference between groups in perceived exercise enjoyment, but, the MICT group significantly improved their perceived exercise enjoyment (10.8 ± 14.2; p = 0.021) from baseline to 16 weeks. Both INT and MICT groups decreased their body weight (2.0 ± 0.8 vs. - 5.5 ± 1.4 kg; p < 0.001), BMI (- 0.6 ± 0.3 vs. - 2.1 ± 0.5 kg/m²; p < 0.001), body fat mass (1.4 ± 0.6 vs. - 4.2 ± 1.0 kg; p < 0.001), fasting glucose (- 0.09 ± 0.01 vs. - 0.18 ± 0.02 mmol/L; p = 0.020), and HbA1c (- 0.21 ± 0.09 vs. - 0.12 ± 0.12%; p = 0.001), respectively, however, the MICT had greater reductions (GxT: p ≤ 0.05) in body weight, BMI, and body fat than the INT group.

CONCLUSION

Sixteen weeks of MICT is adhered to better and elicits greater improvements in body composition than INT. Nevertheless, both interventions similarly reduced fasting glucose and HbA1c in adults with prediabetes, suggesting either treatment could be effective for T2D prevention.

Monitoring Training Load, Well-Being, Heart Rate Variability, and Competitive Performance of a Functional-Fitness Female Athlete: A Case Study

The aim of this case study was to quantify the magnitude of internal load, acute/chronic workload ratio (ACWR), well-being perception, and heart rate variability (HRV) following 38 weeks of functional-fitness training in a female elite athlete. The internal load was obtained with session rating perceived exertion (session-RPE) while the ACWR was calculated by dividing the acute workload by the chronic workload (four-week average). Furthermore, HRV measurements were analyzed via a commercially available smartphone (HRV4training) each morning upon waking whilst in a supine position. The magnitude of internal load was: the weekly mean total during the 38 weeks was 2092 ± 861 arbitrary units (AU); during the preparation for the Open 2018 was 1973 ± 711 AU; during the Open 2018 it was 1686 ± 412 AU; and during the preparation for the Regionals was 3174 ± 595 AU. The mean ACWR was 1.1 ± 0.5 and 50% of the weeks were outside of the 'safe zone'. The well-being during the 38 weeks of training was 19.4 ± 2.3 points. There were no correlations between training load variables (weekly training load, monotony, ACWR, and HRV), and recuperation subjective variables (well-being, fatigue, sleep, pain, stress, and mood). This case study showed that the training load can be varied in accordance with preparation for a specific competition and ACWR revealed that 50% of the training weeks were outside of the 'safe zone', however, no injuries were reported by the athlete. The effectiveness and cost of these methods are very practical during real world functional-fitness.

The Multimodal Nature of High-Intensity Functional Training: Potential Applications to Improve Sport Performance

Training for sports performance requires the development of multiple fitness components within the same program. In this context, training strategies that have the potential to concomitantly enhance metabolic and musculoskeletal fitness are of great value for athletes and coaches. The purpose of this manuscript is to review the current studies on high-intensity functional training (HIFT) and to assess how HIFT could be utilized in order to improve sport-specific performance. Studies on untrained and recreationally-active participants have led to positive results on aerobic power and anaerobic capacity, and muscular endurance, while results on muscular strength and power are less clear. Still, HIFT sessions can elicit high levels of metabolic stress and resistance training exercises are prescribed with parameters that can lead to improvements in muscular endurance, hypertrophy, strength, and power. As similar training interventions have been shown to be effective in the athletic population, it is possible that HIFT could be a time-efficient training intervention that can positively impact athletes’ performances. While the potential for improvements in fitness and performance with HIFT is promising, there is a clear need for controlled studies that employ this training strategy in athletes in order to assess its effectiveness in this population.

Lactate, Heart Rate and Rating of Perceived Exertion Responses to Shorter and Longer Duration CrossFit® Training Sessions

The aim of this study was to analyze blood lactate concentration (LAC), heart rate (HR), and rating perceived exertion (RPE) during and after shorter and longer duration CrossFit^® sessions. Nine men (27.7 ± 3.2 years; 11.3 ± 4.6% body fat percentage and training experience: 41.1 ± 19.6 months) randomly performed two CrossFit^® sessions (shorter: ~4 min and longer: 17 min) with a 7-day interval between them. The response of LAC and HR were measured pre, during, immediately after, and 10, 20, and 30 min after the sessions. RPE was measured pre and immediately after sessions. Lactate levels were higher during the recovery of the shorter session as compared with the longer session (shorter: 15.9 ± 2.2 mmol/L/min, longer: 12.6 ± 2.6 mmol/L/min; p = 0.019). There were no significant differences between protocols on HR during (shorter: 176 ± 6 bpm or 91 ± 4% HRmax, longer: 174 ± 3 bpm or 90 ± 3% HRmax, p = 0.387). The LAC was significantly higher throughout the recovery period for both training sessions as compared to pre-exercise. The RPE was increased immediately after both sessions as compared to pre-exercise, while there was no significant difference between them (shorter: 8.7 ± 0.9, longer: 9.6 ± 0.5; p = 0.360). These results demonstrated that both shorter and longer sessions induced elevated cardiovascular responses which met the recommendations for gains in cardiovascular fitness. In addition, both training sessions had a high metabolic and perceptual response, which may not be suitable if performed on consecutive days.