High-intensity functional training (HIFT) is an exercise modality that emphasizes functional, multi-joint movements that can be modified to any fitness level and elicit greater muscle recruitment than more traditional exercise. As a relatively new training modality, HIFT is often compared to high-intensity interval training (HIIT), yet the two are distinct. HIIT exercise is characterized by relatively short bursts of repeated vigorous activity, interspersed by periods of rest or low-intensity exercise for recovery, while HIFT utilizes constantly varied functional exercises and various activity durations that may or may not incorporate rest. Over the last decade, studies evaluating the effectiveness of HIIT programs have documented improvements in metabolic and cardiorespiratory adaptations; however, less is known about the effects of HIFT. The purpose of this manuscript is to provide a working definition of HIFT and review the available literature regarding its use to improve metabolic and cardiorespiratory adaptations in strength and conditioning programs among various populations. Additionally, we aim to create a definition that is used in future publications to evaluate more effectively the future impact of this type of training on health and fitness outcomes.

Background:High-intensity functional training (HIFT) is a new training modality that merges high-intensity exercise with functional (multijoint) movements. Even though others exist, CrossFit training has emerged as the most common form of HIFT. Recently, several reports have linked CrossFit training to severe injuries and/or life-threatening conditions, such as rhabdomyolysis. Empirical evidence regarding the safety of this training modality is currently limited.Purpose:To examine the incidence of injuries related to CrossFit participation and to estimate the rate of injuries in a large cross-sectional convenience sample of CrossFit participants from around the world.Study Design:Descriptive epidemiology study.Methods:A total of 3049 participants who reported engaging in CrossFit training between 2013 and 2017 were surveyed.Results:A portion (30.5%) of the participants surveyed reported experiencing an injury over the previous 12 months because of their participation in CrossFit training. Injuries to the shoulders (39%), back (36%), knees (15%), elbows (12%), and wrists (11%) were most common for both male and female participants. The greatest number of injuries occurred among those who participated in CrossFit training 3 to 5 days per week (χ2 = 12.51; P = .0019). Overall, and based on the assumed maximum number of workout hours per week, the injury rate was 0.27 per 1000 hours (females: 0.28; males: 0.26), whereas the assumed minimum number of workout hours per week resulted in an injury rate of 0.74 per 1000 hours (females: 0.78; males: 0.70).Conclusion:Our findings suggest that CrossFit training is relatively safe compared with more traditional training modalities. However, it seems that those within their first year of training as well as those who engage in this training modality less than 3 days per week and/or participate in less than 3 workouts per week are at a greater risk for injuries.

We demonstrated that BMI does not affect the step output of commonly used activity monitors during walking. In addition, 67 m·min⁻¹ seems to be the minimum speed required for accurate step counting, at least for most waist-mounted activity monitors. Finally, the StepWatch, AG7164, and activPAL™ were the most accurate devices on the TM, but only the AG7164 yielded comparable step counts to the StepWatch in the free-living environment.

Toohey, JC, Townsend, JR, Johnson, SB, Toy, AM, Vantrease, WC, Bender, D, Crimi, CC, Stowers, KL, Ruiz, MD, VanDusseldorp, TA, Feito, Y, and Mangine, GT. Effects of probiotic (Bacillus subtilis) supplementation during offseason resistance training in female Division I athletes. J Strength Cond Res XX(X): 000-000, 2018-We examined the effects of probiotic (Bacillus subtilis) supplementation during offseason training in collegiate athletes. Twenty-three Division I female athletes (19.6 ± 1.0 years, 67.5 ± 7.4 kg, and 170.6 ± 6.8 cm) participated in this study and were randomized into either a probiotic (n = 11; DE111) or placebo (n = 12; PL) group while counterbalancing groups for sport. Athletes completed a 10-week resistance training program during the offseason, which consisted of 3-4 workouts per week of upper- and lower-body exercises and sport-specific training. Athletes consumed DE111 (DE111; 5 billion CFU/day) or PL supplement daily for the entire 10-week program. Before and after training, all athletes underwent 1 repetition maximum (1RM) strength testing (squat, deadlift, and bench press), performance testing (vertical jump and pro-agility), and isometric midthigh pull testing. Body composition (body fat [BF]%) was completed using BODPOD and bioelectrical impedance analysis, as well as muscle thickness (MT) measurement of the rectus femoris (RF) and vastus lateralis using ultrasonography. Separate repeated-measures analyses of variance were used to analyze all data. Significant (p ≤ 0.05) main effects for time were observed for improved squat 1RM, deadlift 1RM, bench press 1RM, vertical jump, RF MT, and BF%. Of these, a significant group × time interaction was noted for BF% (p = 0.015), where greater reductions were observed in DE111 (-2.05 ± 1.38%) compared with PL (-0.2 ± 1.6%). No other group differences were observed. These data suggest that probiotic consumption in conjunction with post-workout nutrition had no effect on physical performance but may improve body composition in female Division I soccer and volleyball players after offseason training.

High Intensity Functional Training (HIFT) is a training modality, characterized by multimodal exercises performed at high-intensity. Little is known about the training adaptations that occur as a prolonged training program. The purpose of this study was to examine changes in body composition, bone metabolism, strength, and skill-specific performance over 16-weeks of HIFT. Twenty-six recreationally active adult males (n = 9; 34.2 ± 9.1 y; 91.5 ± 17.7 kg; 178.5 ± 5.4 cm) and females (n = 17 = 36.4 ± 7.9 y; 91.5 ± 17.7 kg; 162.9 ± 7.0 cm) completed pre and post training assessments of body composition (Dual-Energy X-Ray Absorptiometry) and performance measures. Performance was assessed using three HIFT workouts (WOD 1–3) to assess strength, skill, and metabolic performance. Aside from the body composition measurements, all assessments were carried out at the local training facility. Training included participation in HIFT a minimum of twice a week for 16-weeks. Repeated measures analysis of variance revealed a significant gender x time interaction in Bone Mineral Content (BMC) (p = 0.027), where improvements favored women (1.0% ± 1.1%, p = 0.004) over men (-0.1% + 0.8%, p = 0.625). Further, region-specific analysis indicated that women (2.5% ± 3.0%, p < 0.005) experienced greater improvements in the trunk compared to men (-0.3% ± 1.8%, p = 0.621), while changes in leg BMC were comparable between women (0.8% ± 1.0%, p < 0.001) and men (0.3% ± 0.6%, p < 0.001). Although no other interactions were observed, significant performance improvements were noted for all participants in WOD 1 (18.3% ± 16.8%), absolute 5RM (14.4% ± 9.7%), relative 5RM (15.4% ± 9.2%), WOD 2 (5.7% ± 6.5%), and WOD 3 (–17.3% ± 14.7%). These data indicate that 16-weeks of HIFT resulted in positive outcomes in strength, metabolic conditioning performance, and body composition.

Turning the LFE on lessens the underestimation of steps recorded at walking speeds ≤54 m·min for both the GT3X and GT1M. However, the increased sensitivity provided by the AG's LFE results in overestimation of steps taken throughout the day, when compared with the criterion device. Meanwhile, failure to turn the LFE on results in an underestimation of steps taken throughout the day.

High-intensity functional training (HIFT) (i.e., CrossFit (CF) training) uses a combination of movements and self-selected time periods of work and rest. However, little is known about the physiological responses to an acute bout of HIFT exercise or about the physical parameters that distinguish performance. The purpose of this study was to examine the physiological responses in advanced CF athletes to consecutive Wingate trials with short, active recovery periods. Twenty-nine advanced-level CF-trained athletes volunteered for this study. The participants were required to complete 4 consecutive Wingate anaerobic tests (WAnTs) and a 15-min CF-style workout. Across the 4 WAnT trials, significant (p < 0.001) changes were observed in oxygen consumption, respiratory exchange ratio, and heart rate. Significant (p ≤ 0.001) differences among WAnT trials were observed in all anaerobic performance measures. Compared with all other trials, greater peak power (p < 0.04), relative peak power (p < 0.02), average power (p < 0.001), relative average power (p < 0.001), and total work (p < 0.001), together with a lower fatigue index (p < 0.01), were observed during WAnT 1. Overall, the 4 consecutive WAnT trials resulted in a significant (F = 177.0, p < 0.001) increase in blood lactate response. Stepwise regression revealed that the ability to predict total repetitions completed during the 15-min trial to complete as many repetitions as possible improved as the participants progressed from the first to the third WAnT trial. Our data suggest that, combined with the ability to better maintain performance across high-intensity exercise bouts, the ability to quickly recover between bouts is the most important factor in CF performance.

The 2018 CrossFit Open (CFO) was the initial stage of an annual competition that consisted of five weekly workouts. Current evidence suggests that a variety of fitness parameters are important for progressing beyond this stage, but little is known about which are the most important. To examine relationships between CFO performance, experience, and physiological fitness, sixteen experienced (>2 years) athletes (30.7 ± 6.9 years, 171 ± 12 cm, 78.0 ± 16.2 kg) volunteered to provide information about their training and competitive history, and then complete a battery of physiological assessments prior to competing in the 2018 CFO. Athletes’ resting energy expenditure, hormone concentrations, body composition, muscle morphology, cardiorespiratory fitness, and isometric strength were assessed on two separate occasions. Spearman correlations demonstrated significant (p < 0.05) relationships between most variables and performance on each workout. Stepwise regression revealed competition experience (R2 = 0.31–0.63), body composition (R2 = 0.55–0.80), vastus lateralis cross-sectional area (R2 = 0.29–0.89), respiratory compensation threshold (R2 = 0.54–0.75), and rate of force development (R2 = 0.30–0.76) to be the most common predictors. Of these, body composition was the most important. These fitness parameters are known targets with established training recommendations. Though preliminary, athletes may use these data to effectively train for CFO competition.