Purpose A small share of the world's population meets current physical activity guidelines, which recommend regular engagement in endurance, strength, and neuromotor exercise. As lack of time represents a major cause of inactivity, multidimensional training methods with short durations may provide a promising alternative to classical, volume‐oriented approaches focusing on one biomotor ability. This trial examined the effects of a high‐intensity functional circuit training (HIFCT) on motor performance and exercise motivation in untrained adults. Methods Thirty‐three inactive participants were randomly allocated to two groups exercising for six weeks. The intervention group (HIFCT, n = 20) 3×/week performed functional whole‐body exercises in a circuit. Each 15‐minute workout included repetitive 20s all‐out bouts with 10s breaks. In the comparison group (moderate aerobic exercise, MAE, n = 13), the participants walked 3×/week for 50 minutes at moderate intensity. Measured motor outcomes were cycling endurance capacity (respiratory threshold, maximum workload), maximum strength (leg and chest press), postural control (force plate), and jump capacity (counter‐movement jump, single leg hop for distance); exercise motivation was assessed using the self‐concordance index. Results In comparison with MAE, HIFCT enhanced maximum leg strength (between‐group difference of relative pre‐ to post‐changes of 5.0%), shoulder strength (7.6%), and endurance workload (5.0%; P < 0.05), while increasing motivation to exercise (+5.5 points, P < 0.05). No between‐group differences occurred for postural control and jump capacity (P > 0.05). Conclusion Despite considerably shorter training duration, HIFCT enhances motor function and motivation to exercise more effectively than MAE. Further research should investigate the long‐term adherence to the program and its effectiveness in other settings.

Knee acoustic emissions provide information about joint health and loading in motion. As the reproducibility of knee acoustic emissions by vibroarthrography is yet unknown, we evaluated the intrasession and interday reliability of knee joint sounds. In 19 volunteers (25.6 ± 2.0 years, 11 female), knee joint sounds were recorded by two acoustic sensors (16,000 Hz; medial tibial plateau, patella). All participants performed four sets standing up/sitting down (five repetitions each). For measuring intrasession reliability, we used a washout phase of 30 min between the first three sets, and for interday reliability we used a washout phase of one week between sets 3 and 4. The mean amplitude (dB) and median power frequency (Hz, MPF) were analyzed for each set. Intraclass correlation coefficients (ICCs (2,1)), standard errors of measurement (SEMs), and coefficients of variability (CVs) were calculated. The intrasession ICCs ranged from 0.85 to 0.95 (tibia) and from 0.73 to 0.87 (patella). The corresponding SEMs for the amplitude were ≤1.44 dB (tibia) and ≤2.38 dB (patella); for the MPF, SEMs were ≤13.78 Hz (tibia) and ≤14.47 Hz (patella). The intrasession CVs were ≤0.06 (tibia) and ≤0.07 (patella) (p < 0.05). The interday ICCs ranged from 0.24 to 0.33 (tibia) and from 0 to 0.82 (patella) for both the MPF and amplitude. The interday SEMs were ≤4.39 dB (tibia) and ≤6.85 dB (patella) for the amplitude and ≤35.39 Hz (tibia) and ≤15.64 Hz (patella) for the MPF. The CVs were ≤0.14 (tibia) and ≤0.08 (patella). Knee joint sounds were highly repeatable within a single session but yielded inconsistent results for the interday reliability.

Plantar foot SMR increases hamstring extensibility, which is explained by age to a small degree. Additional research is warranted in order to delineate the substrate of remote exercise effects. Besides mechanical force transmission, also cortical adaptations might represent the driving factor.

A glenohumeral internal rotation deficit (GIRD) of the shoulder, is associated with an increased risk of shoulder injuries in tennis athletes. The aim of the present study was to reveal the impact of 1) age, sex, specific training data (i.e. training volume, years of tennis practice, years of competitive play) and 2) upper extremity injuries on GIRD in youth competitive tennis athletes. A cross-sectional retrospective study design was adopted. Youth tennis players (n = 27, 12.6 ± 1.80 yrs., 18 male) belonging to an elite tennis squad were included. After documenting the independent variables (anthropometric data, tennis specific data and history of injury), the players were tested for internal (IR) and external (ER) shoulder rotation range of motion (RoM, [°]). From these raw values, the GIRD parameters ER/IR ratio and side differences and TRoM side differences were calculated. Pearson's correlation analyses were performed to find potential associations of the independent variables with the GIRD outcomes. A significant positive linear correlation between the years of tennis training and IR side asymmetry occurred (p < .05). A significant negative linear relation between the years of tennis training and the ratio of ER to IR range of motion (RoM) in the dominant side (p < .05) was found. The analysis of covariance showed a significant influence of the history of injuries on IR RoM (p < .05). Injury and training history but not age or training volume may impact on glenohumeral internal rotation deficit in youth tennis athletes. We showed that GIRD in the dominant side in youth tennis players is progressive with increasing years of tennis practice and independent of years of practice associated with the history of injuries. Early detection of decreased glenohumeral RoM (specifically IR), as well as injury prevention training programs, may be useful to reduce GIRD and its negative consequences.

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BackgroundPhysical inactivity and sedentary behavior are modifiable risk factors for an unhealthy lifestyle in university students. The aim of this study was to identify subgroups among German university students with an increased risk for unhealthy behavior. For this purpose, differences in physical activity and sedentary behavior with respect to sociodemographic and study related factors were examined.MethodsA total of 4,351 students participated in an online survey. The amount of physical activity (metabolic equivalent of task-min/week) and the sitting time (h/day) were assessed using the German short form of the International Physical Activity Questionnaire. Differences in gender and age as well as field of study, targeted degree and study semester were analyzed using a single factorial ANOVA with Tukey correction or a Welch-ANOVA with Games-Howell correction.ResultsFor physical activity, significant differences were found for gender (F(2, 80.46) = 17.79, p &lt; 0.001, ηp2 = 0.009), for field of study (F(5, 1738.09) = 7.41, p &lt; 0.001, ηp2 = 0.01), and for study semester (F(1, 948.12) = 5.53, p &lt; 0.05, ηp2 =0.001), but not for age and targeted degree (p &gt; 0.05). For sedentary behavior, significant differences were found for field of study (F(5, 3816) = 5.69, p &lt; 0.001, ηp2 = 0.01) and targeted degree (F(3, 3868) = 3.94, p &lt; 0.01, ηp2 = 0.003), but not for gender, age and study semester (p &gt; 0.05).ConclusionFemale students, students enrolled in “natural sciences, mathematics and informatics” and first year students appear to have an increased risk of an unhealthy lifestyle. Future research should identify barriers to and incentives of physical activity as well as reasons for high amounts of SB in sub-populations of university students. Suitable prevention and intervention programs are necessary.