The relationship between strength asymmetries and jumping performance in professional volleyball players

Knee peak torque (PT) is associated to jump performance in volleyball players. It is not clear whether muscle strength imbalances of the knee joint can influence jump performance. The purpose of study was to analyse the association between PT and knee muscular imbalances with jump performance in professional volleyball players. Eleven elite male volleyball players (90.3 ± 9.7 kg body mass and 1.94 ± 0.06 m height) were evaluated in an isokinetic dynamometer at speeds of 60, 180 and 300 deg/s. Muscle strength imbalances were obtained through calculation of contralateral deficit between limbs and the conventional ratio (hamstrings/quadriceps). Countermovement jump (CMJ) was performed on a force plate to calculate mechanical power and height. Association was found between knee extensor PT at 180 deg/s with CMJ power (r = 0.610, p = 0.046). Conventional ratio at 300 deg/s showed negative association with CMJ (r = ?0.656, p = 0.029). The optimal ratio between knee extensors PT in relation to the flexors PT is associated with the greater mechanical power in CMJ. Contralateral deficit does not seem to be associated with the CMJ performance. Considering the knee extensor PT is associated with CMJ power, our findings suggest that strength-based training in volleyball athletes should not omit the conventional muscle ratio.     

Heart rate recovery after aerobic and anaerobic tests: is there an influence of anaerobic speed reserve?

The present study assessed if differences in the metabolic profile, inferred from the anaerobic speed reserve (ASR), would influence the dynamics of heart rate recovery (HRR) after two modes of exercise. Thirty-nine physical education students (14 females and 25 males) volunteered for this study. Participants carried out three separate testing sessions to assess maximal sprinting speed (MSS, 1st session), repeated sprint ability (RSA, 2nd session) and maximal aerobic speed (MAS) using the Université of Montreal Track Test (UMTT, 3rd session). ASR was defined as the difference between MSS and MAS. Heart rate was continuously registered throughout the tests and during the 5-min post-test recovery. To evaluate the influence of ASR on post-exercise, HRR comparisons between ASR-based groups [high ASR vs. low ASR] and sex groups (males vs. females) were performed. Significant differences (P < 0.05) were found between high ASR and low ASR groups of the same sex for indices of relative HRR after the RSA and UMTT. In addition, after the RSA test, males from the high ASR group had a significantly slower HRR kinetics compared with the males of the low ASR (P < 0.05) and the females of high ASR (P < 0.05); whereas females of the high ASR groups had a faster HRR kinetics compared with the females of low ASR group (P < 0.05). Our results showed that in males, post-exercise HRR could be related to the ASR, whereas in females, the influence of ASR is less clear.     

Differences in soccer kicking type identified using principal component analysis

Soccer kicks are characterized by segmental and joint rotations in multiple planes, where large discrepancies between two- and three-dimensional analyses for angular measurements of soccer kicks exist. The aim of this study was to clarify the differences in motions of the lower limbs and the pelvis required to achieve a shot without rotations as compared with an instep kick. Kinematic parameters obtained from non-rotational shots and instep kicks were analyzed using principal component analysis (PCA). The results clearly demonstrated that the PCA identified the differences in the instep kick and the non-rotational shot relative to the kinematic motions of the lower limbs and the pelvis. These findings suggest that the key issue for executing the NR shot is achieving a straight-line foot trajectory in the impact phase.     

Mental Health Help-Seeking Experience and Attitudes in Asian American,Multiracial American,and White American Emerging Adults

In this cross-sectional survey, we examined the direct and indirect mental health help-seeking experiences and relevant psychological factors in Asian American, multiracial American, and White American emerging adults aged 18–25 years old. The study sample consisted of 384 Asian American (249 women, 135 men), 244 multiracial American (172 women, 72 men), and 245 White American (190 women, 55 men) emerging adults, who were recruited from a four-year public university in the state of Hawai?i of the United States (U.S.). Results revealed that Asian American and multiracial American emerging adults were less likely to: (a) have previous experience of seeking professional psychological services: (b) have been prescribed, or are currently taking, a psychotropic medication; (c) know someone close to them who had sought psychological services; or (d) know someone close to them who was diagnosed with a psychological disorder, compared to their White American peers. We also discuss implications of the present findings, limitations of the study, and future directions in this line of research.

     

Analysis of the distance covered by Brazilian professional futsal players during official matches

The purpose of this study was to measure and characterise the distances covered by Brazilian professional futsal players. The trajectories of 93 players during five matches were obtained using an automatic tracking method. The distances covered were analysed for different game conditions: over the entire game and during the times when the ball was out of play and in play separately. When the entire game was considered, the results showed that there was a reduction in the total distance covered per minute from the first [median ± IQR (interquartile range): 97.9 ± 16.2 m/min] to the second half (median = 90.3 m/min; IQR = 12.0), and when only the in-play time was considered (first half: 136.6 ± 17.2 m/min; second half: 129.2 ± 16.7 m/min). The percentage of distance covered in the standing and walking velocity range was higher in the second half than in the first when considering the entire game (30.8% and 28.0%, respectively) and during the in-play time (19.3% and 16.2%, respectively). In conclusion, this study verified that futsal players reduced the physical performance during the second half.     

Scientific evidence by fluorescence spectrometry for safflower red on ancient Japanese textiles stored in the Shosoin Treasure House repository

Shosoin textiles, handed down from the eighth century in Nara, Japan, have entranced many people with their beautiful colors made from natural dyes. Dye analysis of the Shosoin textiles, including the red carpet laid inside the workshop hall at the Todaiji Temple in Nara, used for the inauguration of the statue of the Great Buddha in the temple in 752 AD; a red undergarment and a gown with a tie-dyed design worn by craftsmen in the Todaiji Temple; and embroidered shoes belonging to Empress Komyo (701–760 AD), were conducted by excitation–emission matrix fluorescence spectrometry equipped with a fiber optics probe. Comparison of the spectra to references identified safflower red (Carthamus tinctorius L.) in the red or orange areas on these original textiles. The spectrometry of the gown and the shoes offered the identification not only of safflower red but also of amur cork tree. This study finds these examples to be the oldest scientifically confirmed presence of safflower red on historic textiles at present.