Background: This study aimed to examine the immediate effects of the Nordic Hamstring Exercise (NHE) on the stiffness of the biceps femoris (BF) and semitendinosus (ST) muscles. Methods: This parallel-group randomised controlled trial followed CONSORT 2025 guidelines. Twenty-four physically active adults (16 females, 8 males) were randomly assigned to an NHE group (n = 12) or a control group (n = 12) using 1:1 gender-stratified randomisation. The NHE group performed 3 sets of 10 repetitions of the NHE, while the control group remained inactive. Muscle stiffness of the BF and ST was assessed pre- and post-intervention using the MyotonPro device. Results: No significant overall changes in hamstring stiffness were observed within or between groups (p > 0.05). Within the NHE group, the ST tended to increase in stiffness (11.25 N/m, p = 0.057), while the BF showed a small, non-significant reduction (−12.00 N/m, p = 0.696). The difference in changes between BF and ST was significant (p = 0.039). Independent of group allocation, males demonstrated significantly higher baseline stiffness than females for BF (258.13 vs. 195.81 N/m, p < 0.001) and for ST (247.88 vs. 174.00 N/m, p = 0.003). Regression analysis showed that only height predicted the change in ST stiffness after NHE (R = 0.625, R² = 0.39, p = 0.030). Conclusions: A single NHE session did not alter overall hamstring stiffness but produced opposite, muscle-specific effects. More research with larger, uniform samples is needed to confirm these findings.

Dancers are subjected to high-intensity workouts when they practice dancesport, and according to the literature, they are prone to injury, primarily of the lower limbs. The purpose of this study was to determine whether differences exist in relative activation amplitudes for dancers involved in dancesport due to muscle, gender, and type of dance. Measurements were carried out using surface electromyography equipment during the choreography of a performance in the following leg muscles: rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius medialis. Eight couples of active dancesport athletes (aged 20.50±2.75 yrs) were analyzed. Significant gender differences were found in rumba in the tibialis anterior (p≤0.05) and gastrocnemius medialis (p≤0.05). Based on the different activations, it is possible to establish possible mechanisms of injury, as well as tools for preventing injuries and improving sports performance.

The aim of the present study was to develop a predictive model of academic achievement (school success or failure) by applying a decision tree analysis. A cross-sectional study was carried out to design a system for the early detection of academic failure. 219 adolescents (aged 14 to 16) participated and information on their socioeconomic status, body mass index (BMI) percentile, physical activity, leisure time spent in front of screens, enjoyment, hope, anger, anxiety, boredom, behavioral engagement, emotional engagement, cognitive engagement, self-perceived school performance and intention to go to university was collected as input variables in decision tress analysis. 6 failure and 3 success groups were found able to predict academic performance. Good accuracy was obtained in the training (80.11 %) and validation (81.40 %) datasets of the decision tree. It is possible to predict academic failure or success by assessing weight status, physical activity, anger and hope during school attendance, intention to go to university and self-perceived school performance.

This study aimed to describe the response of heart rate (HR) and the subjective rating of perceived exertion (RPE) during a simulated DanceSport competition. The mean and maximum HR of 18 dancers of the highest level were evaluated during a simulated DanceSport competition consisting of 5 Latin dances. RPE values were recorded immediately after each dance. The dances were ranked as follows according to the mean HR (samba [165.3 ± 16.3 bpm] < rumba bolero [176.9 ± 9.9 bpm] < cha-cha-chá [179.1 ± 11.4 bpm] = paso doble [182.5 ± 12.5 bpm] = jive [184.3 ± 11.4 bpm]); maximum HR (samba [185.6 ± 8.9 bpm] = rumba bolero [187.0 ± 9.1 bpm] < cha-cha-chá [190.1 ± 8.0 bpm] = paso doble [191.4 ± 9.0 bpm] < jive [194.2 ± 8.1 bpm]); and RPE (rumba bolero [5.22 ± 1.40] < samba [6.42 ± 2.06] = cha-cha-chá [6.78 ± 1.31] = paso doble [7.39 ± 1.04] < jive [8.33 ± 0.91]). The only significant correlation between RPE and HR values was observed for the maximum HR during the first dance of the competition (samba) (r = 0.485). A simulated DanceSport competition causes high physiological stress being influenced by the type of dance.

Background and Objectives: Hamstring strain injuries (HSIs) are frequent and recurrent in athletes who perform high-speed running. The long head of the biceps femoris (BFlh) is often affected by HSIs. While the Nordic hamstring exercise (NHE) is used for prevention, evidence shows it mainly activates the semitendinosus (ST) instead of the biceps femoris (BF). It was argued that hamstrings may contract isometrically during sprinting’s late swing phase; exercises like the single-leg Roman Chair-Hold (RCH) might better mimic sprinting. Limited electromyographic (EMG) data compare NHE and RCH. This study examined EMG activation of BF and ST during both exercises in athletes. Materials and Methods: Thirty-six professional handball players (17 females, 19 males) were randomly assigned to NHE (n = 18; mean age 22.1 ± 3.9 years) or RCH (n = 18; mean age 22.6 ± 4.9 years). A wireless EMG system recorded dominant leg BFlh and ST activity, normalised to maximal voluntary isometric contraction (MVIC%). NHE participants completed one set of ten repetitions; RCH participants performed three sets of ten repetitions with progressive loads (bodyweight, +10 kg, +20 kg). Results: RCH led to a significantly higher mean BFlh activation in the third set with +20 kg weight compared to NHE (72.9% versus 46.5%; p < 0.001, g = 1.52). BFlh activation steadily increased across RCH sets, coinciding with additional load increments (p < 0.001). Conversely, NHE produced greater ST activation than the RCH at the first set, where RCH was performed with only bodyweight (p < 0.001). Conclusions: NHE primarily activates the ST, while RCH gradually increases BFlh activation, particularly under load. Future research should investigate which exercises are more effective at reducing HSIs to draw more robust conclusions based on the study’s findings.