Effects of an Injury Prevention Program in CrossFit Athletes: A Pilot Randomized Controlled Trial.

The present study aimed to assess the effects of an injury prevention program in CrossFit athletes. Thirty-two CrossFit athletes were randomized to either an intervention group (n=16), that performed mobility and stability exercises during the warm-up of all CrossFit sessions for a 10-week period or to a control group (n=16) that kept performing their usual warm-up. Incidence of injuries (primary outcome) as well as average training loads, fatigue and pain perception were registered during the study. The overall injury incidence rate was 0.04 per 1000 training hours, with no differences between groups (p>0.05). Similarly, no between-group differences were found for injury severity, nor for average training volume, intensity, training load, pain, or fatigue perception during the study (all p>0.05 with trivial-to-small effect sizes). In summary, a 10-week injury prevention program consisting of stability and mobility exercises provided no benefits on injury rates, fatigue and pain perception in recreational CrossFit athletes. Further research might corroborate the preliminary evidence reported here.

Time to Exhaustion at the Respiratory Compensation Point in Recreational Cyclists.

The time to exhaustion (tlim) at the respiratory compensation point (RCP) and whether a physiological steady state is observed at this workload remains unknown. Thus, this study analyzed tlim at the power output eliciting the RCP (tlim at RCP), the oxygen uptake (VO2) response to this effort, and the influence of endurance fitness. Sixty male recreational cyclists (peak oxygen uptake [VO2peak] 40-60 mL∙kg∙min-1) performed an incremental test to determine the RCP, VO2peak, and maximal aerobic power (MAP). They also performed constant-load tests to determine the tlim at RCP and tlim at MAP. Participants were divided based on their VO2peak into a low-performance group (LP, n = 30) and a high-performance group (HP, n = 30). The tlim at RCP averaged 20 min 32 s ± 5 min 42 s, with a high between-subject variability (coefficient of variation 28%) but with no differences between groups (p = 0.788, effect size = 0.06). No consistent relationships were found between the tlim at RCP and the different fitness markers analyzed (RCP, power output (PO) at RCP, VO2peak, MAP, or tlim at MAP; all p > 0.05). VO2 remained steady overall during the tlim test, although a VO2 slow component (i.e., an increase in VO2 >200 mL·min-1 from the third min to the end of the tests) was present in 33% and 40% of the participants in HP and LP, respectively. In summary, the PO at RCP could be maintained for about 20 min. However, there was a high between-subject variability in both the tlim and in the VO2 response to this effort that seemed to be independent of fitness level, which raises concerns on the suitability of this test for fitness assessment.

Functional Threshold Power: Relationship With Respiratory Compensation Point and Effects of Various Warm-Up Protocols.

PURPOSE: The functional threshold power (FTP), which demarcates the transition from steady state to non-steady-state oxidative metabolism, is usually determined with a 20-minute cycling time trial that follows a standard ∼45-minute warm-up. This study aimed to determine if the standard warm-up inherent to FTP determination is actually necessary and how its modification or removal affects the relationship between FTP and the respiratory compensation point (RCP). METHODS: A total of 15 male cyclists (age 35 [9] y, maximum oxygen uptake 66.4 [6.8] mL·kg-1·min-1) participated in this randomized, crossover study. Participants performed a ramp test for determination of RCP and maximum oxygen uptake. During subsequent visits, they performed a 20-minute time trial preceded by the "standard" warm-up that is typically performed before an FTP test (S-WU), a 10-minute warm-up at the power output (PO) corresponding to 60% of maximum oxygen uptake (60%-WU), or no warm-up (No-WU). FTP was computed as 95% of the mean PO attained during the time trial. RESULTS: Although the FTP was correlated with the RCP independently of the warm-up (r = .89, .93, and .86 for No-WU, 60%-WU, and S-WU, respectively; all Ps < .001), the PO at RCP was higher than the FTP in all cases (bias ± 95% limits of agreement = 57 [24], 60 [23], and 57 [32] W for No-WU, 60%-WU, and S-WU, respectively; all Ps < .001 and effect size > 1.70). CONCLUSIONS: The FTP is highly correlated with the RCP but corresponds to a significantly lower PO, being these results independent of the warm-up performed (or even with no warm-up).

Physiological Predictors of Competition Performance in CrossFit Athletes.

The aim of this study was to determine the physiological variables that predict competition performance during a CrossFit competition. Fifteen male amateur CrossFit athletes (age, 35 ± 9 years; CrossFit experience, 40 ± 27 months) performed a series of laboratory-based tests (incremental load test for deep full squat and bench press; squat, countermovement and drop jump tests; and incremental running and Wingate tests) that were studied as potential predictors of CrossFit performance. Thereafter, they performed the five Workouts of the Day (WODs) corresponding to the CrossFit Games Open 2019, and we assessed the relationship between the laboratory-based markers and CrossFit performance with regression analyses. Overall CrossFit performance (i.e., final ranking considering the sum of all WODs, as assessed by number of repetitions, time spent in exercises or weight lifted) was significantly related to jump ability, mean and peak power output during the Wingate test, relative maximum strength for the deep full squat and the bench press, and maximum oxygen uptake (VO2max) and speed during the incremental test (all p < 0.05, r = 0.58-0.75). However, the relationship between CrossFit Performance and most laboratory markers varied depending on the analyzed WOD. Multiple linear regression analysis indicated that measures of lower-body muscle power (particularly jump ability) and VO2max explained together most of the variance (R2 = 81%, p < 0.001) in overall CrossFit performance. CrossFit performance is therefore associated with different power-, strength-, and aerobic-related markers.

Warming Up Before a 20-Minute Endurance Effort: Is It Really Worth It?

PURPOSE: To analyze the effects of different warm-up protocols on endurance-cycling performance from an integrative perspective (by assessing perceptual, neuromuscular, physiological, and metabolic variables). METHODS: Following a randomized crossover design, 15 male cyclists (35 [9] y; peak oxygen uptake [VO2peak] 66.4 [6.8] mL·kg-1·min-1) performed a 20-minute cycling time trial (TT) preceded by no warm-up, a standard warm-up (10 min at 60% of VO2peak), or a warm-up that was intended to induce potentiation postactivation (PAP warm-up; 5 min at 60% of VO2peak followed by three 10-s all-out sprints). Study outcomes were jumping ability and heart-rate variability (both assessed at baseline and before the TT), TT performance (mean power output), and perceptual (rating of perceived exertion) and physiological (oxygen uptake, muscle oxygenation, heart-rate variability, blood lactate, and thigh skin temperature) responses during and after the TT. RESULTS: Both standard and PAP warm-up (9.7% [4.7%] and 12.9% [6.5%], respectively, P < .001), but not no warm-up (-0.9% [4.8%], P = .074), increased jumping ability and decreased heart-rate variability (-7.9% [14.2%], P = .027; -20.3% [24.7%], P = .006; and -1.7% [10.5%], P = .366). Participants started the TT (minutes 0-3) at a higher power output and oxygen uptake after PAP warm-up compared with the other 2 protocols (P < .05), but no between-conditions differences were found overall for the remainder of outcomes (P > .05). CONCLUSIONS: Compared with no warm-up, warming up enhanced jumping performance and sympathetic modulation before the TT, and the inclusion of brief sprints resulted in a higher initial power output during the TT. However, no warm-up benefits were found for overall TT performance or for perceptual or physiological responses during the TT.

Full-Squat as a Determinant of Performance in CrossFit.

This study analyzed the relationship between CrossFit performance and power and strength variables measured in the full-squat exercise. Twenty male trained subjects (33±7 years) performed an incremental load full-squat test for assessment of the 1-repetition maximum (1RM) and the mean (Pmean) and peak (Ppeak) power. Performance in 5 different Workouts of the Day (WODs) was measured on different days, and overall CrossFit performance was determined as the sum of the scores obtained in these WODs. Athletes were then assigned to a high (HP) or low (LP) performance group based on the median score for overall performance. Correlation analysis between squat variables and performance was performed and between-group differences were assessed. Moderate to strong (r=0.47-0.69, p<0.05) positive correlations were found between squat variables and performance in the different WODs. Overall CrossFit performance was strongly and positively associated with absolute (r=0.62, p=0.01) and relative 1RM (r=0.65, p=0.07), and relative Pmean (r=0.56, p=0.02) and Ppeak (r=0.53, p=0.03). Large differences (effect sizes ranging 1.1-1.7, all p<0.05) were observed between HP and LP for absolute and relative 1RM, relative Pmean, and absolute and relative Ppeak. In summary, strength and power indexes measured in a squat test are positively associated with CrossFit performance.