Assessment of Cardiorespiratory and Metabolic Contributions in an Extreme Intensity CrossFit® Benchmark Workout.

Our purpose was to characterize the oxygen uptake kinetics (VO2), energy systems contributions and total energy expenditure during a CrossFit® benchmark workout performed in the extreme intensity domain. Fourteen highly trained male CrossFitters, aged 28.3 ± 5.4 years, with height 177.8 ± 9.4 cm, body mass 87.9 ± 10.5 kg and 5.6 ± 1.8 years of training experience, performed the Isabel workout at maximal exertion. Cardiorespiratory variables were measured at baseline, during exercise and the recovery period, with blood lactate and glucose concentrations, including the ratings of perceived exertion, measured pre- and post-workout. The Isabel workout was 117 ± 10 s in duration and the VO2 peak was 47.2 ± 4.7 mL·kg-1·min-1, the primary component amplitude was 42.0 ± 6.0 mL·kg-1·min-1, the time delay was 4.3 ± 2.2 s and the time constant was 14.2 ± 6.0 s. The accumulated VO2 (0.6 ± 0.1 vs. 4.8 ± 1.0 L·min-1) value post-workout increased substantially when compared to baseline. Oxidative phosphorylation (40%), glycolytic (45%) and phosphagen (15%) pathways contributed to the 245 ± 25 kJ total energy expenditure. Despite the short ~2 min duration of the Isabel workout, the oxygen-dependent and oxygen-independent metabolism energy contributions to the total metabolic energy release were similar. The CrossFit® Isabel requires maximal effort and the pattern of physiological demands identifies this as a highly intensive and effective workout for developing fitness and conditioning for sports.

Acute Responses in Blood Flow Restriction Low-intensity Aerobic Training: A Meta-analysis.

The purpose was to determine the effect low-intensity training with blood flow restriction (LI-BFR) versus high-intensity aerobic training (HIT) on acute physiological and perceptual responses. The Cumulative Index to Nursing and Allied Health Literature, National Library of Medicine, Scopus, SPORTDiscus and Web of Science databases and the reference list of eligible studies were consulted to identify randomized experimental studies, published until July 4, 2022, that analyzed physiological or perceptual responses between LI-BFR versus HIT in healthy young individuals. Mean difference (MD) and standardized mean difference (SMD) were used as effect estimates and random effects models were applied in all analyses. Twelve studies were included in this review. During exercise sessions, HIT promoted higher values of heart rate (MD=28.9 bpm; p<0.00001; I 2 =79%), oxygen consumption (SMD=4.01; p<0.00001; I 2 =83%), ventilation (MD=48.03 l/min; p=0.0001; I 2 =97%), effort (SMD=1.54; p=0.003; I 2 =90%) and blood lactate (MD=3.85 mmol/L; p=0.002; I 2 =97%). Perception of pain/discomfort was lower in HIT (SMD=-1.71; p=0.04; I 2 =77.5%). In conclusion, LI-BFR promotes less pronounced physiological responses than HIT but with greater perception of pain.

Ischemic Preconditioning Improves Resistance Training Session Performance.

ABSTRACT: da Silva Novaes, J, da Silva Telles, LG, Monteiro, ER, da Silva Araujo, G, Vingren, JL, Silva Panza, P, Reis, VM, Laterza, MC, and Vianna, JM. Ischemic preconditioning improves resistance training session performance. J Strength Cond Res 35(11): 2993-2998, 2021-The aim of this study was to investigate the acute effect of ischemic preconditioning (IPC) in a resistance exercise (RE) training session on the number of repetitions performed, total volume, and rating of perceived exertion in recreationally trained and normotensive men. Sixteen recreationally trained and normotensive men completed 3 RE sessions in a counterbalanced and randomized order: (a) IPC protocol using 220 mm Hg followed by RE (IPC), (b) IPC cuff control protocol with 20 mm Hg followed by RE (CUFF), and (c) no IPC (control) followed by RE (CON). RE was performed with 3 sets of each exercise (bench press, leg press, lateral pulldown, hack machine squat, shoulder press, and Smith back squat) until concentric muscular failure, at 80% of one repetition maximum, with 90 seconds of rest between sets and 2 minutes of rest between exercises. Ischemic preconditioning and CUFF consisted of 4 cycles of 5 minutes of occlusion/low pressure alternating with 5 minutes of no occlusion (0 mm Hg) using a pneumatic tourniquet applied around the subaxillary region of the upper arm. For each condition, the number of repetitions completed, total volume of work performed, and rating of perceived exertion were determined. No significant difference was found for rating of perceived exertion between any experimental protocol. Ischemic preconditioning significantly (p < 0.05) increased the number of repetitions across exercises. Consequently, total volume performed (sum of total number of repetitions x load for each exercise) was significantly higher in IPC (46,170 kg) compared with CON (34,069 kg) and CUFF (36,590 kg) across all exercises. This work may have important implications for athletic populations because it demonstrates increase in muscle performance outcomes during a single RE session. Therefore, performing IPC before RE could be an important exercise prescription recommendation to increase maximum repetition performance and total volume of work performed and thus potentially increase desired training adaptations (i.e., strength and hypertrophy).

Comparison of Post-Exercise Hypotension Responses in Paralympic Powerlifting Athletes after Completing Two Bench Press Training Intensities.

Background and objective: Post-exercise hypotension, the reduction of blood pressure after a bout of exercise, is of great clinical relevance. Resistance exercise training is considered an important contribution to exercise training programs for hypertensive individuals and athletes. In this context, post-exercise hypotension could be clinically relevant because it would maintain blood pressure of hypertensive individuals transiently at lower levels during day-time intervals, when blood pressure is typically at its highest levels. The aim of this study was to compare the post-exercise cardiovascular effects on Paralympic powerlifting athletes of two typical high-intensity resistance-training sessions, using either five sets of five bench press repetitions at 90% 1 repetition maximum (1RM) or five sets of three bench press repetitions at 95% 1RM. Materials and Methods: Ten national-level Paralympic weightlifting athletes (age: 26.1 ± 6.9 years; body mass: 76.8 ± 17.4 kg) completed the two resistance-training sessions, one week apart, in a random order. Results: Compared with baseline values, a reduction of 5-9% in systolic blood pressure was observed after 90% and 95% of 1RM at 20-50 min post-exercise. Furthermore, myocardial oxygen volume and double product were only significantly increased immediately after and 5 min post-exercise, while the heart rate was significantly elevated after the resistance training but decreased to baseline level by 50 min after training for both training conditions. Conclusions: A hypotensive response can be expected in elite Paralympic powerlifting athletes after typical high-intensity type resistance-training sessions.

The Influence of Warm-Up on Body Temperature and Strength Performance in Brazilian National-Level Paralympic Powerlifting Athletes.

Background and Objectives: The effects of warm-up in athletic success have gained strong attention in recent studies. There is, however, a wide gap in awareness of the warm-up process to be followed, especially in Paralympic powerlifting (PP) athletes. This study aimed to analyze different types of warm-up on the physical performance of PP athletes. Materials and Methods: The sample consisted of 12 elite Brazilian PP male athletes (age, 24.14 ± 6.21 years; bodyweight, 81.67 ± 17.36 kg). The athletes performed maximum isometric force (MIF), rate of force development (RFD), and speed test (Vmax) in three different methods of warm-up. Tympanic temperature was used to estimate the central body temperature. Results: A significant difference was observed for MIF in the without warm-up (WW) condition in relation to the traditional warm-up (TW) and stretching warm-up (SW) (p = 0.005, η2p = 0.454, high effect). On the contrary, no significant differences were observed in RFD, fatigue index (FI) and time in the different types of warm up (p > 0.05). Furthermore, no significant differences were observed in relation to the maximum repetition (p = 0.121, η2p = 0.275, medium effect) or the maximum speed (p = 0.712, η2p = 0.033, low effect) between the different types of warm up. In relation to temperature, significant differences were found for the TW in relation to the "before" and "after" conditions. In addition, differences were found between WW in the "after" condition and SW. In addition, WW demonstrated a significant difference in relation to TW in the "10 min later" condition (F = 26.87, p = 0.05, η2p = 0.710, high effect). Conclusions: The different types of warm-up methods did not seem to provide significant differences in the force indicators in elite PP athletes.

Exercise prescription for patients with type 2 diabetes-a synthesis of international recommendations: narrative review.

BACKGROUND: Physical activity is a cornerstone of type 2 diabetes treatment and control. AIM: We analysed and synthesised the guidelines and recommendations issued by scientific organisations, regarding exercise prescription for patients with type 2 diabetes. METHOD: A systematic bibliographic search in Pubmed, Web of Science and Scopus databases was conducted. Clinical guidelines from major international scientific organisations in the field of diabetology, endocrinology, cardiology, public health and sports medicine were also considered. 11 publications were selected. RESULTS: Published guidelines recommend a weekly accumulation of a minimum of 150 min of aerobic exercise at moderate-to-vigorous intensity spread over a minimum of 3 days per week. Resistance exercise for muscle strengthening is also recommended at least 2 days a week. Flexibility exercises may complement other types of exercise. Combining aerobic and resistance exercise within the same exercise session is recommended by most guidelines. CONCLUSIONS: Exercise prescription for individuals with type 2 diabetes should include specific information on the type, mode, duration, intensity and weekly frequency. The exercise strategies must be adapted for each individual, based on comorbidities, contraindications and realistic personal goals.

A Randomized Trial Investigating the Influence of Strength Training on Quality of Life in Ischemic Stroke.

BACKGROUND: Strength training post stroke is widely acknowledged as an important part of a rehabilitation program. Muscle strength has been shown to be a significant contributor to physical disability after stroke, which in turn has an immense impact on the reintegration of patients into society, affecting their quality of life. OBJECTIVE: This was a randomized intervention trial to determine the effect of a resistance training program on the quality of life in patients with stroke. METHODS: An experimental group (EG), consisting of 11 subjects aged 51.7 ± 8.0 years, and a control group (CG), consisting of 13 subjects aged 52.5 ± 7.7 years, were studied before and after 12 weeks. EG underwent 12 weeks of strength training three times a week. The CG did not undergo strength training during the 12-week study period. RESULTS: There was a significant increase in quality of life from pre-test to post-test (Δ% = 21.47%; p = 0.021) in EG. There were significant differences in all indicators of quality of life between groups at 12 weeks. There were greater gains in strength in EG than in CG (p ≤ 0.05). There was a negative correlation between the strength gains as determined with the 1RM test and the quality of life, especially in lower limb exercises. CONCLUSION: The results of this study indicate that there was an improvement in the measures of strength in EG, and that there was a correlation between improvements in strength and quality of life in these patients who had previously suffered a stroke at least one year prior to study.

Influence of number of sets on blood pressure and heart rate variability after a strength training session.

The purpose of this study was to compare the acute effects of 1, 3, and 5 sets of strength training (ST), on heart rate variability (HRV) and blood pressure. Eleven male volunteers (age: 26.1 ± 3.6 years; body mass: 74.1 ± 8.1 kg; height: 172 ± 4 cm) with at least 6 months previous experience in ST participated in the study. After determining the 1 repetition maximum (1RM) load for the bench press (BP), lat pull down (LPD), shoulder press (SP), biceps curl (BC), triceps extension (TE), leg press (LP), leg extension (LE), and leg curl (LC), the participants performed 3 different exercise sequences in a random order and 72 hours apart. During the first sequence, subjects performed a single set of 8-10 repetitions, at 70% 1RM, and with 2-minute rest interval between exercises. Exercises were performed in the following order: BP, LPD, SP, BC, TE, LP, LE, and LC. During the second sequence, subjects performed the same exercise sequence, with the same intensity, 2-minute rest interval between sets and exercises, but with 3 consecutive sets of each exercise. During the third sequence, the same protocol was followed but with 5 sets of each exercise. Before and after the training sessions, blood pressure and HRV were measured. The statistical analysis demonstrated a greater duration of postexercise hypotension after the 5-set program vs. the 1 set or 3 sets (p ≤ 0.05). However, the 5-set program promoted a substantial cardiac stress, as demonstrated by HRV (p ≤ 0.05). These results indicate that 5 sets of 8-10 repetitions at 70% 1RM load may provide the ideal stimulus for a postexercise hypotensive response. Therefore, ST composed of upper- and lower-body exercises and performed with high volumes are capable of producing significant and extended postexercise hypotensive response. In conclusion, strength and conditioning professionals can prescribe 5 sets per exercises if the goal is to reduce blood pressure after training. In addition, these findings may have importance, specifically in the early phase of high blood pressure development, but more research is needed in hypertensive populations to validate this hypothesis.

Subcutaneous and Visceral Fat: Relation with Brown Adipose Tissue Activation in Women.

Brown adipose tissue (BAT) helps control body weight and is inversely correlated with body fat, but it is unclear whether it is subcutaneous adipose tissue (SAT) or visceral adipose tissue (VAT) that is related to BAT activation. The presented study aimed to verify the relation of SAT and VAT on BAT activation through infrared thermography (IRT) and cold stimulation in adult women. Forty women were evaluated in body composition and skin temperature (Tskin) acquisition by IRT. Student's independent t-test, Pearson's correlation, and two-way repeated measures ANOVA with Tukey post-hoc were applied. Women with low amounts of SAT and VAT had a significant increase in supraclavicular Tskin (SCVT). Medium negative degrees of linear variation were found before and after cold stimulation between SCVT, SAT and VAT. A significant effect of the moment factor and the group factor on the SCVT between subjects divided into the groups were pointed out. No difference was found in the relation between SAT, VAT, and BAT in adult women, pointing out that both types of fat are equally related. These results can help clinical practice understand clearly, through IRT, that the high accumulation of SAT and VAT can impair the activation of BAT and hinder the loss of weight in women.

Effect of the Fran CrossFit Workout on Oxygen Uptake Kinetics, Energetics, and Postexercise Muscle Function in Trained CrossFitters.

PURPOSE: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake (V˙O2) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. METHODS: Twenty trained CrossFitters performed Fran at maximal exertion. V˙O2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. RESULTS: A marked increase in V˙O2 kinetics was observed at the beginning of Fran, remaining elevated until the end (V˙O2peak: 49.2 [3.7] mL·kg-1·min-1, V˙O2 amplitude: 35.8 [5.2] mL·kg-1·min-1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. CONCLUSIONS: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue.

Do Men and Women Differ in Hematological Adaptations to 24 Weeks of Crossfit® Training?

Regular exercise can modulate the immune system functioning through changes in the number and function of leukocytes as well as in red blood cells and other typical blood markers. High intensity exercise promotes increases in cytotoxic activity, phagocytic capacity, chemotaxis and cell apoptosis. The aim of the study was to compare the chronic effects of a 24-week training program using CrossFit® methodology on hematological variables of men vs. women. Twenty-nine CrossFit® athletes (35.3 ± 10.4 years, 175.0 ± 9.2 cm, 79.5 ± 16.4 kg) participated in the study. The blood count, the lipid profile and glucose markers were measured every two months during the study period. The erythrocyte count and hemoglobin concentrations increased in months 4 and 6 in men and women, respectively. Hematocrit levels increased in men in months 2, 4 and 6, while in women only in month 6. Red cell distribution width increased in men in month 6 when compared to the value in month 2. Segmented neutrophils increased in men in month 6 and eosinophil levels increased in women in month 6. Differences between the two sexes were observed in monocytes levels at baseline, as well as in months 2, 4 and 6. Cross-Fit® training increased red cell count indicators in both sexes, which may be related to increased erythropoiesis. Some white blood cell counts were altered and these differed between sexes. The number of lymphocytes remained stable throughout the experiment.

Corrigendum: Enhancing performance: unveiling the physiological impact of submaximal and supramaximal tests on mixed martial arts athletes in the -61 kg and -66 kg weight divisions.

[This corrects the article DOI: 10.3389/fphys.2023.1257639.].

Prevention of exercise-related injuries and adverse events in patients with type 2 diabetes.

Physical activity is widely recommended as an essential non-pharmacological therapeutic strategy to the prevention and control of type 2 diabetes and cardiovascular risk. Microvascular and macrovascular complications associated with the natural progression of the disease and typical age and anthropometric profile of individuals with type 2 diabetes may expose these patients to an increased risk of injury and acute adverse events during exercise. These injuries and adverse events can lead to fear of new injury and consequent physical inactivity. Preventative measures are essential to reduce risk, increase safety and avoid the occurrence of exercise-related injuries in people with type 2 diabetes. This population can exercise safely if certain precautions are taken and if exercise is adapted to complications and contraindications of each individual. Conditions such as diabetic foot, diabetic retinopathy, diabetic nephropathy, diabetic autonomic neuropathy, cardiovascular risk factors, musculoskeletal disorders, hypoglycaemia, hyperglycaemia, dehydration and interactions between medication and exercise should be taken into consideration when prescribing exercise.

Influence of the Competitive Level and Weight Class on Technical Performance and Physiological and Psychophysiological Responses during Simulated Mixed Martial Arts Fights: A Preliminary Study.

This study aimed to analyze the influence of the competitive level and weight class on technical performance and physiological and psychophysiological responses during simulated MMA fights. Twenty MMA male athletes were divided into four groups: heavyweight elite (HWE; n = 6), lightweight elite (LWE; n = 3), heavyweight professional (HWP; n = 4), and lightweight professional (LWP; n = 7). All athletes performed four simulated fights of three 5-min rounds with a 1-min rest interval. Each fight was recorded using a video camera to analyze offensive and defensive actions. Moreover, the following measures were made: heart rate (before and after each round), blood lactate concentration (before and after the fight), readiness state (before each round), and the rate of perceived exertion (RPE) (after each round). The main findings were: i) LWE athletes applied more offensive touches than LWP athletes; ii) HWP athletes presented higher heart rate values than LWP athletes after the first round; however, LWP athletes presented greater heart rate changes than HWP athletes from the first to the second round; iii) no differences existed between groups in blood lactate concentration and readiness state; and iv) HWP and LWP athletes presented higher RPE values than LWE athletes in the first and third rounds; however, LWE athletes presented greater RPE changes than HWE, HWP, and LWP athletes from the first to the second and third rounds. This study shows that LWE athletes apply more offensive touches than LWP athletes during simulated MMA fights. Moreover, lightweight athletes tend to increase their physiological demand as the combat evolves, which is also reflected in their RPE.

Reduction of leptin levels during acute exercise is dependent on fasting but not on caloric restriction during chronic exercise: A systematic review and meta-analysis.

BACKGROUND: The importance of leptin in controlling body mass has recently gained more attention. Its levels are directly associated with the amount of fat mass, but not necessarily dependent on it. Exercise has great potential in reducing leptin levels, however the response of exercise to this cytokine is still not well understood. OBJECTIVE: The objective of the review was to analyze the effects of physical exercise on plasma leptin concentration, either acutely (post-exercise/training session) and/or after a training period (short- or long-term), as well as to investigate the existence of possible moderating variables. METHODS: The studies included in this systematic review were published between 2005 and May 2023. Only peer-reviewed studies, available in English, performed with humans that evaluated the effects of any form of exercise on leptin levels were included. The search was conducted on May 03, 2023, in Embase (Elsevier), MEDLINE via PubMed®, and Web of Science (Core collection). The risk of bias in the included trials was assessed by the Physiotherapy Evidence Database tool, considering 11 questions regarding the methodology of each study with 10 questions being scored. The data (n, mean, and standard deviation) were extracted from included studies to perform random effects meta-analyses using standardized mean difference between the pre- and post-intervention effects. RESULTS: Twenty-five studies (acute effect: 262 subjects; short- and long-term effect: 377 subjects) were included in this systematic review and meta-analysis. Short- and long-term physical exercise and caloric restriction plus exercise reduce plasma leptin levels, presenting statistically significant differences (p<0.001); as well as acute effect (p = 0.035), however the latter result was influenced by the pre-exercise meal as shown in the subgroup analysis. In this meta-analysis the effect of moderating factors on leptin reduction, not addressed by past reviews, is verified, such as the relationship with caloric restriction, exercise intensity and pre-exercise meal on acute responses. CONCLUSION: Both acute and chronic exercise reduce leptin levels, yet the acute effect is dependent on the pre-exercise meal. In addition to having a long-term reduction in leptin levels, the minimum amount of weekly exercise to have a significant reduction in plasma leptin is 180 minutes of moderate-intensity exercise and 120 minutes of high-intensity exercise.

Bioenergetic Analysis and Fatigue Assessment During the Fran Workout in Experienced Crossfitters.

AIM: To quantify the physiological demands and impact of muscle function t of the Fran workout, one of the most popular CrossFit benchmarks. METHODS: Twenty experienced CrossFitters-16 male: 29 (6) years old and 4 female: 26 (5) years old- performed 3 rounds (with 30-s rests in between) of 21-21, 15-15, and 9-9 front squats to overhead press plus pull-up repetitions. Oxygen uptake and heart rate were measured at baseline, during the workout, and in the recovery period. Rating of perceived exertion, blood lactate, and glucose concentrations were assessed at rest, during the intervals, and in the recovery period. Muscular fatigue was also monitored at rest and at 5 minutes, 30 minutes, and 24 hours postexercise. Repeated-measures analysis of variance was performed to compare time points. RESULTS: Aerobic (52%-29%) and anaerobic alactic (30%-23%) energy contributions decreased and the anaerobic lactic contribution increased (18%-48%) across the 3 rounds of the Fran workout. Countermovement jump height decreased by 8% (-12 to -3) mean change (95% CI), flight duration by 14% (-19 to -7), maximum velocity by 3% (-5 to -0.1), peak force 4% (-7 to -0.1), and physical performance (plank prone 47% [-54 to -38]) were observed. CONCLUSIONS: It appears that the Fran workout is a physically demanding activity that recruits energy from both aerobic and anaerobic systems. This severe-intensity workout evokes substantial postexercise fatigue and corresponding reduction in muscle function.

Smart Devices for Health and Wellness Applied to Tele-Exercise: An Overview of New Trends and Technologies Such as IoT and AI.

This descriptive article explores the use of smart devices for health and wellness in the context of telehealth, highlighting rapidly evolving technologies such as the Internet of Things (IoT) and Artificial Intelligence (AI). Key innovations, benefits, challenges, and opportunities related to the adoption of these technologies are outlined. The article provides a descriptive and accessible approach to understanding the evolution and impact of smart devices in the tele-exercise reality. Nowadays, technological advances provide solutions that were unthinkable just a few years ago. The habits of the general population have also changed over the past few years. Hence, there is a need to investigate this issue and draw the attention of the scientific community to this topic by describing the benefits and challenges associated with each topic. If individuals no longer go to exercise, the exercise must go to their homes instead.