Retrospective Study of Risk Factors and the Prevalence of Injuries in HIFT.

The aim of this study was to investigate the risk factors and the incidence of injuries in high-intensity functional training (HIFT) practitioners. A survey was administered to 213 HIFT practitioners. Participants reported the number of injuries, the location of the injuries, and training exposure during the preceding six months and answered questions regarding potential risk factors for injury. We found there were 7.1 injuries for every 1000 hours of training. In addition, we found that individuals with experience in the modality (>2 years) were 3.77 times more likely to be affected by injury when compared with beginner individuals (<6 months) (CI95%=1.59-8.92; p=0.003). When the analysis was performed only for the competitive level, we found that practitioners competing at the national level were 5.69 times more likely to experience an injury than competitors who do not compete (CI95%=1.10-29.54; p=0.038). We also found that the injuries mainly affect the shoulder and lumbar regions. It was possible to conclude that subjects with a higher level of experience in the modality are more likely to be affected by injuries and that the shoulder and lumbar areas are most likely to be injured during HIFT.

Mental Fatigue Reduces Training Volume in Resistance Exercise: A Cross-Over and Randomized Study.

The present study aimed to determine the effect of mental fatigue (MF) on total training volume (TTV; number of repetitions x number of sets x load) and on ratings of perceived exertion (RPE; Borg, 1982) in the half-back squat exercise (HBSE). Nine male subjects (M age = 22.6 years, SD = 2.3; M height = 172.3 cm, SD = 6.8; M weight = 76.2 kg, SD = 9.8; M years of resistance training experience = 4.1, SD = 2.3 years) recruited from a university population were study participants in this participant-blind cross-over and randomized study. Participants underwent either the Stroop task - a highly demanding cognitive task (CT) - or a control condition (CON) in which they viewed a documentary exhibition for 30 minutes. Perception of MF and motivation were assessed after treatments using a visual analog scale of 100 mm. Participants then engaged in a countermovement jump (CMJ) test and three sets of HBSE until they reached momentary concentric failure, reporting RPE at the end of each exercise set. Following the CT, participants showed a significantly increased self-perception of MF in relation to the CON condition (p = 0.01; d = 1.2), but this did not affect their motivation to engage in subsequent tests (p = 0.99; d = 0.006). Neither the CMJ performances nor the RPE were statistically different between CT and CON conditions (p = 0.33; d = 0.09 and p = 0.20; η2 = 0.20, respectively). TTV was significantly lower in the CT relative to the CON experimental condition (Δ = -15.8%; p = 0.04; η2 = 0.48). Prolonged involvement in a CT was associated with reduced volume on a resistance exercise, though this effect was not associated with changes in CMJ performance or motivation to exercise.

The stretch-shortening cycle efficiency is dependent on the maturational stage / A eficiência do ciclo alongamento-encurtamento é dependente do estágio maturacional

Abstract Maturation interferes with physiological and mechanical aspects of muscle contraction. The aim of the present study was to compare the efficiency of the stretch-shortening cycle (SSC) between different maturation stages. One hundred forty six young people, with 72 boys and 74 girls, were recruited to participate in the study. Sexual maturation was measured and the group was stratified into adolescents (> 3 auto-tanner) and children (<2 auto-tanner). Squat jump (SJ) and countermovement jump (CMJ) performance were measured to measure reactive force (RF) capacity, eccentric utilization ratio (EUR) and pre-stretch augmentation (PSAP). The children did not present statistical difference between SJ and CMJ (t(55)= -1.93; ∆ = -0.61; 95% CI = -1.24 to -0.02; p = 0.058), while the adolescents presented higher performance of CMJ (t(89)= -12.28; ∆ = -2.44; 95% CI = -2.84 to -2.05; p <0.001). In addition, adolescents had higher RF performance (t(144)= 5.18; p <0.0001; 95% CI = 2.53 to 1.13), PSAP (t(144)= 4.38; p <0.0001; 95% CI = 14.00 to 5.29) and EUR (t(144)= 4.38; p <0.0001; 95% CI = 0.14 to 0.05). We conclude that more mature young people have better SSC utilization.

Resumo Maturação interfere em aspectos fisiológicos e mecânicos da contração muscular. O objetivo do estudo foi comparar a eficiência do ciclo alongamento-encurtamento (SSC) em diferentes estágios maturacionais. Cento e quarenta e seis jovens, sendo 72 meninos e 74 meninas, foram recrutados para participar do estudo. Maturação sexual foi mensurada e o grupo foi estratificado em adolescentes (≥ 3 e crianças (< estágio 2). Salto estático (SJ) e o salto contramovimento (CMJ) foram utilizados para mensurar a força reativa (RF), razão de utilização da excêntrica (EUR) e aumento do pré-estiramento (PSAP). As crianças não apresentaram diferença significante entre SJ e CMJ (t(55)= -1.93; ∆ = -0.61; 95% CI = -1.24 to -0.02; p = 0.058), Enquanto que os adolescentes apresentaram maior desempenho de CMJ (t(89)= -12.28; ∆ = -2.44; 95% CI = -2.84 to -2.05; p <0.001). Em adição, adolescentes apresentaram maior RF (t(144)= 5.18; p <0.0001; 95% CI = 2.53 to 1.13), PSAP (t(144)= 4.38; p <0.0001; 95% CI = 14.00 to 5.29) e EUR (t(144)= 4.38; p <0.0001; 95% CI = 0.14 to 0.05). Nós concluímos que jovens com mais maturados apresentam maior capacidade de utilização do SSC.