BACKGROUND: Cryotherapy is widely utilized for therapeutic purposes, yet its specific effects on knee joint proprioception and quadriceps muscle performance in healthy individuals remain unclear. This study addresses this gap by examining the impact of a 20-minute cryotherapy session on knee joint proprioception and related muscle parameters in a cohort of healthy college students. OBJECTIVES: To investigate the effects of cryotherapy on knee joint proprioception and quadriceps muscle peak moment, work and power in healthy college male and female students. METHODS: Thirty-two healthy students, aged 19–23, underwent a 20-minute cryotherapy session using Cryogel packs applied to the anterior thigh and knee. An isokinetic dynamometer measured knee joint proprioception and quadriceps muscle parameters before, immediately after, 10-min, and 20-min post-cryotherapy. RESULTS: Proprioception values did not significantly differ between genders or post-tests ([Formula: see text] 0.05). However, the female group exhibited significantly lower moment, power, and work values compared to males ([Formula: see text] 0.05). No significant differences were observed within or between post-tests in moment, power, and work for both genders ([Formula: see text] 0.05). CONCLUSIONS: A 20-minute cryotherapy application demonstrated no adverse effects on knee joint proprioception or quadriceps muscle metrics in healthy college students, supporting the safety of cryotherapy in this context.

BACKGROUND: Long-time judo training can lead athletes to develop upper limb asymmetry and shoulder asymmetry during force production, mainly in the action of pulling, pushing, and throwing; that requires higher strength and velocity of the internal and external rotators of the shoulders, which may also result in shoulder injury, or a decrease in judo performance. OBJECTIVE: To investigate asymmetries in concentric force of the internal and external shoulder rotators of the dominant and non-dominant upper limbs in high-level judokas at angular velocities of 60, 180, and 300∘/s. METHODS: 14 highly trained male judokas (age 24.4 [Formula: see text] 4.8 yrs.; body mass 87.9 [Formula: see text] 18.7 kg; height 1.8 [Formula: see text] 0.1 m). All participants performed 5 attempts of movement concentric internal and external rotation of the shoulder with 3 angular velocities (60∘/s, 180∘/s, and 300∘/s) in an isokinetic dynamometer (Cybex® Humac Norm Dynamometer CSMI, model 502140). The data were analyzed by independent t-student (discrete analysis) a statistical parametric mapping (SPM) curve (one-dimensional analysis). RESULTS: There was no difference in dominant vs. non-dominant for discrete analysis ([Formula: see text] 0.05). There was no difference in dominant vs. non-dominant for SPM analysis. None of the comparisons surpassed the comparison cut-off (tcrit) for the [Formula: see text]-test ([Formula: see text] 0.05). CONCLUSIONS: Based on results, judokas do not present significant asymmetries in concentric force of external or internal shoulder rotators when compared to the dominant vs. the non-dominant upper limb according to discrete and one-dimensional (SPM) analysis.

BACKGROUND: Deadlift (DL) and back squat (BSQ) are considered different exercises because of their kinematic and kinetic characteristics. However, there are similarities, such as joint movement and the maximal muscle strength generated. Although there are differences and similarities, it is unclear which is more related to athletic performance. OBJECTIVE: This study aimed to determine the relationship between DL and jump, acceleration, and change of direction and compare whether DL or BSQ differ in their relationship to jumping, acceleration, and change of direction. METHODS: Eighty male volleyball players (age: 19.6 [Formula: see text] 0.9 years, height: 179.2 [Formula: see text] 6.7 cm, mass: 71.9 [Formula: see text] 9.4 kg) volunteered to participate in this study. Countermovement jump (CMJ), 10-m sprint, and 1–5 repetition maximum (1–5 RM) BSQ were measured on day 1. The T-test and 1–5 RM DL were measured on day 2. RESULTS: DL had a significant and moderate relationship with all parameters of CMJ ([Formula: see text] 0.328, [Formula: see text] 0.01), 10-m sprint ([Formula: see text] [Formula: see text]0.471, [Formula: see text] 0.01), and T-test ([Formula: see text] [Formula: see text]0.441, [Formula: see text] 0.01). BSQ showed a significant and moderate relationship with the 10-m sprint ([Formula: see text] [Formula: see text]0.489, [Formula: see text] 0.01) and T-test ([Formula: see text] [Formula: see text]0.356, [Formula: see text] 0.01), but a significant and weak relationship only with CMJ ([Formula: see text] 0.289, [Formula: see text] 0.01). In addition, no significant differences were found in the comparison of correlation coefficients ([Formula: see text] 0.05). CONCLUSIONS: Deadlift may be introduced as an alternative exercise to BSQ when there are limitations in the training environment, such as the lack of a squat rack to safely perform BSQ or home confinement due to external factors like pandemics.

BACKGROUND: Beetroot juice is an ergogenic aid containing high levels of nitrate and is known to have many physiological benefits. OBJECTIVE: This study aimed to examine the effects of beetroot juice supplementation on the physical capacity and isokinetic muscle function of power athletes. METHODS: Thirteen power athletes were orally administered three different volumes of beetroot juice: placebo (70 ml), low-volume beetroot juice (70 ml), and high-volume beetroot juice (140 ml). The Harvard step test, 20 m sprint, side-step, reaction time, Wingate test, blood lactate analysis, and isokinetic knee and trunk tests were performed to confirm their physical capacity and isokinetic muscle function. Significant differences between the drink groups were determined using repeated-measures ANOVA. RESULTS: There were no significant differences in the Harvard step, side step, whole-body reaction time, anaerobic power, blood lactate concentration, and isokinetic muscular strength in the knee and trunk for all groups. However, the 20 m sprint and isokinetic muscular endurance of the knee extensor were significantly higher with beetroot juice intake. CONCLUSIONS: Our findings suggest that [Formula: see text] 70 ml of beetroot juice supplement before performance may be useful as an ergogenic supplement to improve performance-related physical fitness, including speed and muscular endurance, in power athletes.

BACKGROUND: The return to activities and sports after the anterior cruciate ligament (ACL) reconstruction is a critical decision. OBJECTIVE: To verify the most used elements during the isokinetic evaluation for discharge after ACL reconstruction. METHODS: Systematic review (PROSPERO CRD42021224433). Research in the literature: PubMed, Medline, SciELO, Lilacs, CENTRAL, PEDro, Web of Science and Embase, in February 2022. Studies that performed isokinetic evaluation during the discharge period in male patients aged 18 to 59 years after ACL reconstruction. Descriptive synthesis on the most used parameters during isokinetic evaluation as a discharge criteria after ACL reconstruction. RESULT: Twenty-three studies involving 1,792 participants were included. Medium and high quality evidence identified that most isokinetic evaluations targeted only muscle strength after rehabilitation of the ACL (peak moment). CONCLUSION: The most used elements during the isokinetic evaluation were: angular velocity of 60∘/s, 1 set of 5 repetitions, concentric mode and peak moment.

BACKGROUND: Muscle fatigue is nearly unavoidable during resistance exercise, yet evaluating it in such circumstances can be challenging. OBJECTIVE: This study aimed to evaluate the validity of using the rating of perceived exertion (RPE) as a measure of muscle fatigue during non-explosive bench press (BP) exercise. METHODS: Fifteen male collegiate athletes participated in three BP tasks set at 65% of their one-repetition maximum. The RPE, spectral fatigue index (SFI), and velocity loss were measured across different experimental conditions. RESULTS: Significant effects were observed across different experimental conditions for the overall RPE, average velocity loss, and average SFI (all [Formula: see text] 0.001). As the lifting tasks progressed, there were significant increases in the RPE, velocity loss, and SFI ([Formula: see text] 0.001). Additionally, significant differences were observed between the experimental conditions in the RPE ([Formula: see text] 0.001), SFI ([Formula: see text] 0.001), and velocity loss ([Formula: see text] 0.01). A significantly stronger ([Formula: see text] 0.05) correlation was observed between the RPE and SFI ([Formula: see text] 0.68, df [Formula: see text] 117, [Formula: see text] 0.001) than between the velocity loss and SFI ([Formula: see text] 0.51, df [Formula: see text] 117, [Formula: see text] 0.001). CONCLUSIONS: The corresponding changes observed in the RPE, velocity loss, and SFI suggest that both the RPE and velocity loss can be used as indicators of muscle fatigue during non-explosive BP exercise. However, due to the strong correlation between the RPE and SFI, RPE is more effective for reflecting muscle fatigue in non-explosive resistance exercise settings. Regarding ease of use, the RPE is more suitable than velocity loss for assessing muscle fatigue in training scenarios.

BACKGROUND: The quantitative recruitment of motor units depends on specific demands, including movement velocity. DNA microarrays differ according to sex, and these sex-related differences affect the fiber type composition. OBJECTIVE: The aim of this study is to demonstrate inter-sex differences in the isokinetic parameters, isokinetic phases, and muscle activities and to investigate the correlation between muscle activity and isokinetic data. METHODS: A total of 41 healthy adults (20 male, 21 female) performed concentric knee extension at angular velocities of 60∘/s, 180∘/s, and 240∘/s. The outcome measures consisted of the isokinetic peak moment (PM), normalized PM (PM/BW), total work, and power, alongside the acceleration, iso-speed and deceleration, sub-phases. Muscle activity was recorded from the rectus femoris, vastus lateralis, and vastus medialis using surface EMG. RESULTS: There were significant two-factor main effect and interaction between sex and angular velocity on the power of knee extension and isokinetic phase (p< 0.05). As the velocity increased, the increase in power of males was greater than that of females. In contrast, with the increase in velocity, PM, PM/BW, and total work decreased, but no significant interaction was observed between velocity and sex. At high velocity, males showed higher acceleration ability than females. CONCLUSION: The sex-dependent responses to velocity were more affected by differences in total movement time than force production. Fast isokinetic exercise should consider the acceleration ability rather than the ability to produce force.

BACKGROUND: Mounting evidence has demonstrated functional and cognitive-related benefits after Instability Resistance Training (IRT) in individuals, healthy as wellas patients presenting with neurological disorders. However, whether IRT may play a significant role in the postural control of older adults has not been established. OBJECTIVE: To evaluate the effects of 12- weeks of IRT on static postural control of older adults with subjective cognitive impairment. METHODS: In this randomized controlled trial, a total of 67 participants (aged 65 years and older) were randomly assigned to either 12 weeks of IRT (n= 22), traditional resistance training (RT) (n= 23), or a health education control group (CON) (n= 22). Static postural control was assessed using a force platform that recorded the displacement amplitude of the center of pressure (CoP) in the anteroposterior (AP) and mediolateral (ML) directions in bipedal support (30 seconds) with eyes open and closed. RESULTS: All groups increased AP displacement in the conditions of eyes open and closed. During the eyes-closed condition, only the IRT group increased the ML displacement. No between-group differences were detected in any postural control (p> 0.05). CONCLUSIONS: 12 weeks of IRT does not improve the static postural control in older adults with cognitive impairment.

BACKGROUND: Those undergoing pelvic floor muscle training (PFMT) often experience difficulty in perception; therefore, an easier PFMT method should be devised. OBJECTIVE: To determine the effectiveness of combining PFMT with either vibration stimulation or visual feedback provided by a branded cushion (not a prototype) in increasing PFM muscle activity. Since PFM does not involve large joint movements, muscle activity was a suitable indicator. METHODS: Twenty healthy adults were included in this study. All participants performed PFMT under three conditions using a branded cushion: vibration stimulation, visual feedback, and a control. All three conditions were provided separately. PFM activity of the midline of the perineum at two points was recorded as the root mean square measured using PFM electromyography, measured twice for each condition. Muscle activity ratio was obtained by calculating maximum voluntary contraction of PFM in pre- and post-PFMT conditions. RESULTS: PFM activity and muscle activity ratio were both significantly higher following PFMT under vibration stimulation and visual feedback conditions (p< 0.01, p< 0.01, respectively). CONCLUSIONS: PFMT accompanied by vibration stimulation or visual feedback could immediately raise PFM muscle activity. We believe this study contributes to improving PFMT efficiency by suggesting more suitable PFMT methods.

BACKGROUND: Measurements of hip abduction (ABD) and adduction (ADD) are important in strength and conditioning as well as in clinical practice. However, there is no clear consensus on how ABD and ADD compare in strength in different populations. OBJECTIVE: The aim was to perform a quantitative synthesis of comparisons between the isometric strength of ABD and ADD in different populations. METHODS: ABD and ADD strength data were collected and pooled mean values for ABD:ADD strength ratio were calculated and expressed as standardized mean differences. Forty studies of healthy adults, 5 studies of healthy older adults and 14 studies of adults with various musculoskeletal injuries were included in the analysis. RESULTS: Healthy (non-athletic) males, healthy older adults, and adults with hip and groin pathologies or osteoarthritis tend to have the same ADD and ABD strength; male athletes tend to have a stronger ADD compared with ABD; healthy females and adults with patellofemoral pain tend to have a stronger ABD compared with ADD. CONCLUSIONS: These results can serve as a database to help compare and interpret measurements of ADD and ABD strength ratio in different populations.