Effects Of High-intensity Functional Training Research Articles

Effects of high-intensity functional training on physical fitness and sport-specific performance among the athletes: A systematic review with meta-analysis.

This study aims to meta-analyze the impact of high-intensity functional training on athletes' physical fitness and sport-specific performance. A systematic search was conducted in five well-known academic databases (PubMed, Scopus, Web of Science, EBSCOhost, and the Cochrane Library) up to July 1, 2023. The literature screening criteria included: (1) studies involving healthy athletes, (2) a HIFT program, (3) an assessment of outcomes related to athletes' physical fitness or sport-specific performance, and (4) the inclusion of randomized controlled trials. The Physical Therapy Evidence Database (PEDro) scale was used to evaluate the quality of studies included in the meta-analysis. 13 medium- and high-quality studies met the inclusion criteria for the systematic review, involving 478 athletes aged between 10 and 24.5 years. The training showed a small to large effect size (ES = 0.414-3.351; all p < 0.05) in improving upper and lower body muscle strength, power, flexibility, and sport-specific performance. High-intensity functional training effectively improves athletes' muscle strength, power, flexibility, and sport-specific performance but has no significant impact on endurance and agility. Future research is needed to explore the impact of high-intensity functional training on athletes' speed, balance, and technical and tactical performance parameters.

A Preliminary Investigation into the Frequency Dose Effects of High-Intensity Functional Training on Cardiometabolic Health.

The objective of this study was to explore the effects of three weekly frequency doses of high-intensity functional training (HIFT) on an array of cardiometabolic markers in adults with metabolic syndrome (MetS). Twenty-one men and women, randomized into one (HIFT1), two (HIFT2), or three (HIFT3) days per week of HIFT, completed 3-weeks of familiarization plus a 12-week progressive training program. Pre- and post-intervention, several cardiometabolic, body composition, oxygen consumption, metabolic syndrome severity, and perceptions of fitness measurements were assessed. Additionally, an exercise enjoyment survey was administered post-intervention. A Cohen's d was used to demonstrate within-group change effect size. Although this study was not fully powered, a one-way and two-way ANOVA were used to compare the dose groups to provide provisional insights. No differences were found when frequency dose groups were compared. Many cardiometabolic, body composition, and fitness improvements were seen within each group, with clinically meaningful improvements in the metabolic syndrome severity score (MSSS) (HIFT1: -0.105, d = 0.28; HIFT2: -0.382, d = 1.20; HIFT3: -0.467, d = 1.07), waist circumference (HIFT1: -4.1cm, d = 3.33; HIFT2: -5.4cm, d = 0.89; HIFT3: -0.7cm, d = 0.20), and blood glucose (HIFT1: -9.5mg/dL, d = 0.98; HIFT2: -4.9mg/dL, d = 1.00; HIFT3: -1.7mg/dL, d = 0.23). All three groups similarly reported high exercise enjoyment and likeliness to continue after the intervention. In conclusion, HIFT performed once, twice, or thrice a week elicits improvements in MetS and is considered enjoyable. HIFT, even at a low weekly dose, therefore represents a potential strategy to reduce the global MetS burden.

The effects of high-intensity functional training on muscle damage and recovery capacity in trained individuals

Objective: High-Intensity Functional Training (HIFT) is nowadays widely used due to low time demand and efficiency to improve performance and health. The dynamics of recovery of muscle damage and physical fitness after a HIFT in individuals with different fitness status provide a practical information for coaches and practitioners. Therefore, the aim of this study was to verify the muscle damage and performance recovery responses after an acute HIFT session in healthy young men with different fitness status.Method: Sixteen recreationally trained participants (age: 23.4 ± 2.4 y; body mass index: 24.6 ± 2.4 kg·m-2; 1RM back squat: 120.1 ± 19.9 kg) were divided into two groups according to their maximum strength (higher-trained [HT] and lower-trained group [LT]), and performed a single HIFT session. Muscle damage (creatine kinase [CK] and lactate dehydrogenase [LDH]) and physical fitness tests (strength, power, and oxygen consumption) were analyzed before, immediately after, 24h and 48h after the HIFT session. The internal training load for both groups was equalized using the Rating of Perceived Exertion method (RPE) and the percentage 1 repetition maximum (1RM).Results: Biochemical markers and performance indicators showed that both groups suffered exercise-induced muscle damage. There was a trend towards faster muscle damage recovery in HT group.Conclusions: HT group showed higher muscle damage recovery compared to the LT group. A longer recovery time to complete muscle recovery might be expected in the LT group.

Effects of High-Intensity Functional Training (HIFT) on the Functional Capacity, Frailty, and Physical Condition of Older Adults with Mild Cognitive Impairment: A Blind Randomized Controlled Clinical Trial.

Physical exercise has been established as an intervention in the integral approach for the physical, functional, and social health of older adults. The objective of this study was to determine the effects of a high-intensity functional training (HIFT) program on the physical condition and functional capacity of an elderly Colombian population with mild cognitive impairment. This research corresponds to a blind randomized controlled clinical trial. A total of 169 men and women aged over 65 years were evaluated and distributed in two groups: the experimental group that received a 12-week HIFT intervention (n = 82) and the control group (n = 87) that received general recommendations on the benefits of physical exercise. The outcome variables included physical condition, assessed using the Senior Fitness battery (SNB); Fried's frailty phenotype was applied, and gait and balance were assessed using the Tinetti scale. For the functional variables, activities of daily living, instrumental activities of daily living, and advanced activities of daily living were evaluated. All variables were measured pre- and post-intervention. Statistically significant improvements were observed in the IG for gait stability and balance (p < 0.001), as well as for independence in activities of daily living (p = 0.003), and instrumental and advanced activities (p < 0.001). Likewise, greater functionality was found when assessed with the SNB (p < 0.001), except for upper limb strength. The frailty classification did not show changes post-intervention (p = 0.170) nor in the group x time interaction. MANCOVA analysis showed that regardless of gender, health level, age, BMI, cognition, and health level, the HIFT intervention produced better results in functional capacity, balance, and gait (F = 0.173, p < 0.001, Wilks' λ = 88.231).

Acute effects of high-intensity functional training with or without whole-body electromyostimulation on serum irisin and brain-derived neurotrophic factor in overweight individuals

Acute effects of high-intensity functional training with or without whole-body electromyostimulation on serum irisin and brain-derived neurotrophic factor in overweight individuals

Measuring the Immediate Effects of High-Intensity Functional Training on Motor, Cognitive and Physiological Parameters in Well-Trained Adults.

The importance of physical activity has been widely demonstrated both in clinics and in sports. One of the new frontier training programs is high-intensity functional training (HIFT). The immediate effects of HIFT on the psychomotor and cognitive performance of well-trained people are still not clear. This paper aims to evaluate the immediate effects induced by HIFT on blood lactate levels, physical performance in terms of body stability and jump ability, and cognitive performance in terms of reaction time. Nineteen well-trained participants were enrolled in the experimental studies and asked to execute six repetitions of a circuit training. Data were gathered both in a pre-training session and after each one of the circuit repetitions. An immediate significant increase with respect to the baseline was observed during the first repetition, with a further increase after the third one. No effects on jump ability were found, whereas a deterioration in body stability was found. Positive immediate effects on cognitive performance in terms of accuracy and speed in task execution were assessed. The findings can be exploited by trainers during coaching to optimize the design of training programs.

Comparing Two Protocols of Exercise on Physical Fitness and Psychological Factors of Mild to Moderate Multiple Sclerosis Patients

Background: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Previous studies have shown that aerobic activity is inversely related to MS symptoms and may be restorative and possibly protective. Objectives: This study aimed to compare the effects of high-intensity functional training (HIFT) protocols and aerobic exercise on functional fitness as well as the cognitive aspect of female patients with multiple sclerosis. Methods: This quasi-experimental and applied clinical trial study consisted of all patients with MS registered in an MS clinic. Among eligible individuals, 30 female RRMS patients were randomly and equally divided into three groups high-intensity functional training (n = 10); aerobic exercise (n = 10), and control group (n = 10). The forearm test, the 30-second standing test, and single leg stance test (SLST), the timed up and go (TUG), Expanded Disability Status Scale (EDSS) were performed to assess physical factors as well as the 21-DAS questionnaire to assess cognitive aspects. Results: This study showed a meaningful difference between the intervention groups and the control group (P &lt; 0.05), in the level of power in the upper body (P = 0.001), lower torso strength (P = 0.001), static balance (P = 0.001), dynamic balance (P = 0.001). the psychological and behavioral components. Conclusions: Present study suggests that aerobic exercise and HIFT in women with MS can improve and further enhance physical function plus psychological and behavioral factors.

The Effects Of High-Intensity Functional Training On Perceptions Of Exercise In Middle-Aged Females

The Effects Of High-Intensity Functional Training On Perceptions Of Exercise In Middle-Aged Females

Acute Effects of High-Intensity Functional Training and Moderate-Intensity Continuous Training on Cognitive Functions in Young Adults.

Background: The purpose of the present study was to compare the influence of an acute bout of high-intensity functional training (HIFT) with an acute bout of moderate-intensity continuous training (MICT) on measures of cognitive function. Methods: Sixty-nine young adults (Mean ± SD: age = 21.01 ± 2.79 yrs; body mass = 69.65 ± 6.62 kg; height = 1.74 ± 0.05 m; Body Mass Index = 22.8 ± 1.41) gave informed consent and were randomly divided into three groups. The HIFT group, with 27 participants, performed a high-intensity (>85% Max. HR) circuit of functional exercises for 30 min. The MICT group, with 28 participants, performed moderate-intensity (70–80% Max. HR) continuous training on a cyclo-ergometer. The control group did not perform any activity. The Stroop Test, Word Recall and N-Back Test were completed to assess during the familiarization period, immediately before and immediately after the training’s bouts. Results: The repeated measures ANOVA did not show significant mean differences for any group. However, the T-Test for the paired samples demonstrated very significant differences in the Stroop Test, in terms of fastest response time (FRT; mean difference (MD) = −1.14, p < 0.01, d = 0.9), mean response time (MRT; MD = −2.16, p < 0.01, d = 0.66) and the number of correct answers (NCA; MD = 1.08, p < 0.05, d = 0.5) in the HIFT group and in the MICT group (FRT; MD = −1.79, p < 0.01, d = 0.9), (MRT; MD = −3.07, p < 0.01, d = 0.9) (NCA; MD = 1.54, p < 0.05, d = 0.5). Conclusions: There were no differences in the control group. HIFT and MICT may elicit specific influences on cognitive function, mainly in executive function and selective attention.

The Effects of High-Intensity Functional Training on Cognition in Older Adults with Cognitive Impairment: A Systematic Review.

(1) Background: High-Intensity Functional Training (HIFT) is a new exercise modality that emphasizes multi-joint functional movements adaptable to any fitness level and promotes greater muscle recruitment. Previous studies have evaluated the positive effects of HIFT on mental and cognitive health but have not evaluated it in older people. This study aims to conduct a systematic review of randomized controlled trials assessing the effects of HIFT on general cognition in older adults with cognitive impairment. (2) Methods: Following the PRISMA 2020 guideline, articles that did a high-intensity functional physical exercise intervention on cognitive performance in older adults with mild to moderate cognitive impairment (MMSE > 10) or dementia, aged 55 years or older, published between 2011 and 2021 in five different electronic databases: PubMed, Web of Science, Scopus, CINAHL, and Cochrane plus were included. (3) Results: 7 articles were included, all having general cognition as their primary outcome. All assessed general cognition using the Mini-Mental State Examination, the ADAS-Cog, or both. All studies had at least one HIFT experimental group with a frequency of 2 sessions per week and a variable duration between protocols of 12, 13, 16, and 26 weeks. Two articles showed that a progressive HIFT program improves general cognition, four articles showed no significant changes within or between groups and one article concluded that a HIFT intervention does not slow cognitive decline. (4) Conclusions: Evidence exists of the benefits of HIFT on general cognition in older adults with cognitive impairment, assessed using the MMSE, the ADAS-cog, or both. Two articles that showed improvement in cognitive function used progressive HIFT with 80% RM at 6, 12, and 1 weeks; however, in the other articles, due to the heterogeneity of intervention protocols, measurement time points, and control group activities, mixed results were evidenced

The effects of high-intensity functional training on cardiometabolic risk factors and exercise enjoyment in men and women with metabolic syndrome: study protocol for a randomized, 12-week, dose-response trial

BackgroundIndividuals with metabolic syndrome (MetS) are at a greater risk for developing atherosclerotic cardiovascular disease (ASCVD) than those without MetS, due to underlying endothelial dysfunction, dyslipidemia, and insulin resistance. Exercise is an effective primary and secondary prevention strategy for MetS; however, less than 25% of adults meet the minimum stated public recommendations. Barriers often identified are lack of enjoyment and lack of time. High-intensity functional training (HIFT), a time-efficient modality of exercise, has shown some potential to elicit positive affectivity and elicit increased fitness and improved glucose metabolism. However, the effects of HIFT on dyslipidemia and endothelial dysfunction have not been explored nor have the effects been explored in a population with MetS. Additionally, no studies have investigated the minimal dose of HIFT per week to see clinically meaningful changes in cardiometabolic health. The purpose of this study is to (1) determine the dose-response effect of HIFT on blood lipids, insulin resistance, and endothelial function and (2) determine the dose-response effect of HIFT on body composition, fitness, and perceived enjoyment and intention to continue the exercise.Methods/designIn this randomized, dose-response trial, participants will undergo a 12-week HIFT intervention of either 1 day/week, 2 days/week, or 3 days/week of supervised, progressive exercise. Outcomes assessed at baseline and post-intervention will be multiple cardiometabolic markers, and fitness. Additionally, the participant’s affective response will be measured after the intervention.DiscussionThe findings of this research will provide evidence on the minimal dose of HIFT per week to see clinically meaningful improvements in the risk factors of MetS, as well as whether this modality is likely to mitigate the barriers to exercise. If an effective dose of HIFT per week is determined and if this modality is perceived positively, it may provide exercise specialists and health care providers a tool to prevent and treat MetS.Trial registrationClinicalTrials.gov NCT05001126. August 11, 2021.

The Effects of High-Intensity Functional Training Compared with Traditional Strength or Endurance Training on Physical Performance in Adolescents: A Randomized Controlled Trial.

Abstract Gavanda, S, Isenmann, E, Geisler, S, Faigenbaum, A, and Zinner, C. The effects of high-intensity functional training compared with traditional strength or endurance training on physical performance in adolescents: a randomized controlled trial. J Strength Cond Res 36(3): 624–632, 2022—High-intensity functional training (HIFT) integrates different modes of exercise into training sessions performed at a relatively high intensity. Although HIFT is becoming more popular in youth strength and conditioning programs, research comparing the effects of HIFT with traditional forms of training, such as strength training (ST) or endurance training (ET) in younger populations are limited. Therefore, the aim of this study was to compare the effects of HIFT with those of ST and ET on strength and endurance performance in adolescents. Fifty-two untrained adolescents ( JOURNAL/jscr/04.03/00124278-202203000-00005/5FFU1/v/2023-10-16T001806Z/r/image-tiff = 26; JOURNAL/jscr/04.03/00124278-202203000-00005/5FFU2/v/2023-10-16T001806Z/r/image-tiff = 26; 17.3 ± 1.0 years) were randomly assigned to a HIFT, ST, ET, or control group. The intervention groups trained twice a week for 6 weeks with a training duration of 60–75 minutes per session. Performance was assessed before and after the intervention with the countermovement jump (CMJ), 20-m sprint (20 m), 3-repetition maximum back squat (3RM), and Yo-Yo test. The HIFT group made significant improvements in all performance tests (CMJ, +28.5 ± 27.6%; p &gt; 0.001; 20-m time, −3.9 ± 5.0%; p = 0.002; 3RM, +34.3 ± 23.3%; p &gt; 0.001; Yo-Yo, +14.5 ± 15.2%; p = 0.003), whereas the ST group improved in CMJ (+38.3 ± 27.7%; p &gt; 0.001), 3RM (+22.2 ± 11.2%; p &gt; 0.001), and Yo-Yo (+12.2 ± 21.4%; p = 0.013) and the ET group improved in CMJ (+23.4 ± 29.9%; p = 0.001), 20-m time (−5.2 ± 4.6%; p &gt; 0.001), and Yo-Yo (+30.7 ± 37.3%; p &gt; 0.001). No significant differences between the groups were evident when the results were compared for sex. These results indicate that HIFT is an effective training method for eliciting multifaceted improvements in strength, power, and endurance measures as compared with ET or ST alone in untrained adolescents.

Effects Of High-intensity Functional Training Using Two Different Resistance Loads On Body Composition And Strength

Effects Of High-intensity Functional Training Using Two Different Resistance Loads On Body Composition And Strength

Chronic effects of high-intensity functional training on motor function: a systematic review with multilevel meta-analysis

High-intensity functional training (HIFT) has become a popular method in the sports and fitness sector. In contrast to unimodal approaches such as strength or endurance training, it has been hypothesized to induce concurrent adaptations in multiple markers of motor function. However, to date, the effectiveness of HIFT in this regard has not been studied. The present systematic review quantified the chronic effects of HIFT on motor function in healthy individuals. A multilevel meta-analysis with a robust random effects meta-regession model was used to pool the standardized mean differences (SMD) between (a) HIFT and (b) no-exercise (NEX) as well as conventional endurance, resistance and balance training for outcomes of muscle strength, endurance capacity and balance. The influence of possible effect modifiers such as program duration, session duration, age or sex was examined in a moderator analysis. Seventeen papers with moderate to high methodological quality (PEDro scale) were identified. Compared to NEX, HIFT had small to moderate positive effects on endurance capacity (SMD: 0.42, 95% CI 0.07–0.78, p = 0.03) and strength (0.60, 95% CI 0.02–1.18, p = 0.04) but no effect on balance (SMD: − 0.10, 95% CI − 1.13 to 0.92, p = 0.42). Regarding endurance, HIFT showed similar effectiveness as moderate-intensity endurance training (SMD: − 0.11, 95% CI − 1.17 to 0.95, p = 0.75) and high-intensity interval endurance training (SMD: − 0.15, 95% CI − 1.4 to 1.1, p = 0.66). No comparisons of HIFT vs. classical resistance or balance training were found. Moderator analyses revealed no influence of most effect modifiers. However, regarding endurance, females seemed to respond more strongly to HIFT in the comparison to NEX (p < .05). HIFT appears to represent an appropriate method to induce chronic improvements in motor function. While being superior to NEX and non-inferior to endurance training, current evidence does not allow a comparison against resistance and balance training. The impact of possible effect moderators should be further elucidated in future research.

The Effects of High-intensity Functional Training (HIFT) on Spatial Learning, Visual Pattern Separation and Attention Span in Adolescents.

Aerobic, anaerobic, and strength exercises are known to improve various cognitive functions, such as executive functions, pattern separation, and working memory. High-intensity functional training (HIFT) is a form of physical activity that can be modified to any fitness level and elicits greater muscle recruitment than repetitive aerobic exercises, thereby improving cardiovascular endurance, strength, and flexibility. HIFT emphasizes functional, multi-joint movements via high-intensity interval training (HIIT) and muscle-strengthening exercises. It is yet unknown, however, whether HIFT affects cognitive functions in adolescents. To address this question, we subjected adolescents to 3 × 20 min training sessions/week of HIFT for 3 months. The effects of HIFT were tested on performance in: (1) virtual reality (VR)-based spatial learning task; (2) computerized visual pattern separation; and (3) attention span. The control group performed a typical physical class three times per week. The effects on cognition were tested at baseline and following 3 months of HIFT. Three months into the intervention, the HIFT group achieved higher scores in the spatial learning task, pattern separation task, and in the attention span test, compared with controls. These data suggest that HIFT can potentially translate into improving school performance in adolescents.

Effects of Six Weeks of High-Intensity Functional Training on Physical Performance in Participants with Different Training Volumes and Frequencies.

High-intensity functional training (HIFT) is characterized by presenting high volumes and training intensities with constantly varied exercises. The aim of this study was to analyze the internal training load and the effects of high-intensity functional training on physical performance in subjects with different training volumes and frequencies. A total of 31 volunteers involved in high-intensity functional training (14 men and 17 women) were divided according to their training volumes and frequencies (high training-volume and frequency—HTVF; (n = 17) (nine women and eight men; age: 31.0 ± 6.3 years; height: 168.8 ± 8.1 cm, body weight: 73.6 ± 11.9 kg; BMI: 25.96 kg/m2) and moderate training volume and frequency—MTVF; (n = 14) (eight women and six men; age: 26.6 ± 4.7 years; height: 167.2 ± 8.6 cm, body weight: 75.8 ± 18.0 kg; BMI: 27.33 kg/m2)). The internal training load was determined using the session-rating of perceived exertion method. The monotony index (MI) and training strain (TS) were used to determine training variability during the training weeks. Countermovement vertical jump height, 20-m sprinting and handgrip strength were assessed at baseline and after six weeks of training. There was a time effect for MI ((F(5, 145) = 5.942; p = 0.0001)), TS ((F(5, 145) = 5.734; p = 0.0001)), weekly internal training load ((F(4.006, 116.87) = 4.188; p = 0.003)) and mean weekly internal training load ((F(4.006, 116.87) = 4.188; p = 0.003)). There was no increase in performance in either group for countermovement vertical jump height ((F(1,29) = 6.081; p = 0.050)), sprinting ((F(1,29) = 1.014; p = 0.322)), right handgrip strength ((F(1,29) = 2.522; p = 0.123)) or left handgrip strength ((F(1,29) = 2.550; p = 0.121)). The current findings suggest that six weeks of high-intensity functional training was not able to increase performance in either group. Therefore, different volumes and frequencies do not seem to influence the increase in physical performance of HIFT practitioners.

Different amount of training affects body composition and performance in High-Intensity Functional Training participants.

The effects of High-Intensity Functional Training (HIFT) on body composition and the relationship of the latter with performance are not well defined. In this work we investigated, by means of Dual-energy X-ray Absorptiometry, the relative proportions of fat-, lean soft tissue-, and mineral mass in CrossFit® (CF, a popular mode of HIFT) participants (n = 24; age, 28.2 ± 3.39 y; BMI, 25.3 ± 2.04 kg/m2) with at least 1 year of CF training experience and weekly amount of training > 10 h/w (n = 13; Higher Training, HT) or < 10 h/w (n = 11; Lower Training, LT) as well as age- matched and BMI-matched physically active controls (CHT, CLT). Performance was assessed in the “Fran” workout. Data were analyzed by one-way or repeated measures ANOVA where needed. Association between variables was assessed with the Pearson’s correlation coefficient r. Partial correlation was used where needed. Results showed that HT performed better than LT in the “Fran” (P < 0.001) and they had higher whole-body bone mineral density (P = 0.026) and higher lean soft mass (P = 0.002), and borderline lower percent fat mass (P = 0.050). The main difference between CF participants (HT, LT) and their respective controls (CHT, CLT) was a lower adiposity in the former. In CF participants, performance positively correlated with appendicular lean soft tissue mass (P = 0.030). It can be concluded that, in CF participants, a higher amount of weekly training improves most notably lean body mass and increases performance in association with increased skeletal muscle mass. CF participation is especially effective in reducing fat mass vs. age- and BMI-matched physically active controls.

High-Intensity Functional Training Improves Cardiorespiratory Fitness and Neuromuscular Performance Without Inflammation or Muscle Damage.

Posnakidis, G, Aphamis, G, Giannaki, CD, Mougios, V, Aristotelous, P, Samoutis, G, and Bogdanis, GC. High-intensity functional training improves cardiorespiratory fitness and neuromuscular performance without inflammation or muscle damage. J Strength Cond Res 36(3): 615-623, 2022-We examined the effects of high-intensity functional training (HIFT) on cardiorespiratory and neuromuscular performance, as well as on inflammatory and muscle damage markers. Thirteen physically active healthy volunteers (aged 28.3 ± 3.8 years, 5 men and 8 women) underwent 8 weeks of a group HIFT program performed 3 times per week. Each session consisted of 4 rounds of a 9-exercise circuit (30-second exercise and 15-second recovery). During the first and last weeks of training, venous blood was sampled daily to monitor changes in serum C-reactive protein (CRP) and creatine kinase (CK). After 8 weeks of HIFT, body fat decreased by 0.64 ± 1.01 kg (p = 0.041), maximal oxygen uptake improved by 1.9 ± 2.2 ml·kg-1·min-1 (p = 0.009), countermovement jump by 2.6 ± 1.5 cm (p = 0.001), bench press 1-repetition maximum (1RM) by 4.5 ± 3.8 kg (p = 0.001), maximum number of bench press repetitions at 65% 1RM by 4 ± 5 repetitions (p = 0.03), and abdominal muscle endurance by 6 ± 4 repetitions (p < 0.001). In both week 1 and week 8 of training, CK increased mildly in the morning after the first session of the week (main effect for day, p = 0.008), whereas no significant changes were observed in CRP (p = 0.31). During week 8, CK on all days was ∼32% lower compared with week 1 (160 vs. 235 U·L-1; main effect of week 1 vs. week 8, p = 0.027), whereas CRP remained unchanged (p = 0.225). This HIFT program was effective in improving cardiorespiratory and neuromuscular physical fitness without causing significant inflammation or muscle damage in physically active subjects.

Effects of Eight Weeks of High Intensity Functional Training on Glucose Control and Body Composition among Overweight and Obese Adults.

High-intensity exercise has been found to positively influence glucose control, however, the effects of high-intensity functional training (HIFT) for overweight and obese sedentary adults without diabetes is unknown. The purpose of this study was to examine changes in body composition and glucose control from eight weeks of aerobic and resistance training (A-RT) compared to HIFT. Session time spent doing daily workouts was recorded for each group. Baseline and posttest measures included height, weight, waist circumference, dual X-ray absorptiometry (body fat percentage, fat mass, lean mass), and fasting blood glucose. Participants completing the intervention (78%, n = 9 per group) were 67% female, age = 26.8 ± 5.5 years, and had body mass index = 30.5 ± 2.9 kg/m2. Fasting blood glucose and 2-h oral glucose tolerance tests were used as primary outcome variables. On average, the HIFT group spent significantly less time completing workouts per day and week (ps < 0.001). No significant differences were found for body composition or glucose variables within- or between-groups. Even though our findings did not provide significant differences between groups, future research may utilize the effect sizes from our study to conduct fully-powered trials comparing HIFT with other more traditional training modalities.

High-Intensity Functional Training (HIFT): Definition and Research Implications for Improved Fitness.

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.