Search

Context: Horizontal hops can provide insight into how athletes can tolerate high-intensity single-leg stretch loads and are commonly used in athlete monitoring and injury management. Variables like flight, contact, and total time provide valuable diagnostic information to sports science professionals. However, gold-standard assessment tools (eg, 3-dimensional motion capture, force plates) require monetary and technological resources. Therefore, we used a tablet and free software to determine the between-rater, within-rater, and test-retest variability of the temporal events of multiple horizontal hop tests., Design: Reliability study., Methods: Nine healthy males (20.8 [1.3] y, 71.4 [9.8] kg, 171.7 [4.5] cm) across various university sports teams and clubs volunteered and performed several triple (3-Hop) and quintuple (5-Hop) horizontal hops over 3 testing sessions. Six raters detected temporal events from video to determine between-rater variability, while a single rater quantified within-session and test-retest variability. The temporal variables of flight time, ground contact time for each individual hop, and the total time of each hoping series were determined. The consistency of measures was interpreted using the coefficient of variation and interclass correlation coefficients (ICC)., Results: Good to excellent between-rater consistency was observed for all hops (ICC = .85-1.00). Absolute (coefficient of variation ≤ 2.0%) and relative consistency (ICC = .98-1.00) was excellent. Test-retest variability showed acceptable levels of absolute consistency (coefficient of variation ≤ 8.7%) and good to excellent consistency in 10/16 variables (ICC = .81-.93), especially those later in the hopping cycle., Conclusions: A tablet and free digitizing software are reliable in detecting temporal events during multiple horizontal hops, which could have exciting implications for power diagnostics and return-to-play decisions. Therefore, rehabilitation and performance professionals can confidently utilize the highly accessible equipment from this study to track multiple hop performances.

The aim of the current study was to evaluate the effect of personalized sleep hygiene education on sleep indices in elite athletes. Nine elite male cricket players performed 3 weeks of baseline sleep monitoring (PRE), followed by group and individualized sleep hygiene education and a further 3 weeks of sleep monitoring (POST). Subjective sleep questionnaires included the Athlete Sleep Behaviour Questionnaire (ASBQ), the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). Objective sleep indices were monitored via wrist actigraphy. There were significant improvements (p < 0.05) in two of the sleep questionnaires (ESS and PSQI) and in sleep efficiency (+5%), sleep latency (-29 min) and sleep onset variance (-28 min) following the intervention, all associated with large or very large effect sizes ( d = 1.38, -0.85 and -0.88, respectively). The current study reports that personalized sleep hygiene education using the ASBQ to target maladaptive sleep behaviours may be effective in acutely improving sleep indices in elite male athletes.

The structures of gas-phase M + (CO 2 ) n (M = Co, Rh, Ir; n = 2-15) ion-molecule complexes have been investigated using a combination of infrared resonance-enhanced photodissociation (IR-REPD) spectroscopy and density functional theory. The results provide insight into fundamental metal ion-CO 2 interactions, highlighting the trends with increasing ligand number and with different group 9 ions. Spectra have been recorded in the region of the CO 2 asymmetric stretch around 2350 cm -1 using the inert messenger technique and their interpretation has been aided by comparison with simulated infrared spectra of calculated low-energy isomeric structures. All vibrational bands in the smaller complexes are blue-shifted relative to the asymmetric stretch in free CO 2 , consistent with direct binding to the metal center dominated by charge-quadrupole interactions. For all three metal ions, a core [M + (CO 2 ) 2 ] structure is identified to which subsequent ligands are less strongly bound. No evidence is observed in this size regime for complete activation or insertion reactions.

Sound rotational power and mobility are an integral component in functional performances, such as throwing and striking. The purpose of this study was to examine the role of rotational power and mobility on cricket ball-throwing velocity. Eleven professional cricketers and 10 under-19 club-level cricketers performed the chop and lift, seated and standing cricket ball throw, seated and standing side medicine ball throw, and seated active thoracic rotation range of motion (ROM) and hip rotation ROM on one occasion. Participants were divided into 2 groups (fast and slow) based on their standing cricket ball-throwing velocity. The seated and standing cricket ball throw on the dominant side was significantly different (p < 0.00) between fast and slow throwers (11.03 and 10.7 km·h(-1), respectively). Muscular performance measures, such as bilateral thoracic rotation ROM, hip external rotation ROM on the dominant side, and force and work required in the chop, were significantly different (p ≤ 0.05) between fast and slow throwers. Faster throwers in this study displayed greater force (18.4%) and work (31.2%) outputs in the chop compared with the slower throwers; however, slower throwers showed significantly greater ROM in the thoracic (13.4-16.8%) and hip regions (11.8%). It was concluded that greater ROM at proximal segments, such as hips and thoracic, may not increase throwing velocity in cricket as reduced ROM at proximal segments can be useful in transferring the momentum from the lower extremity in an explosive task such as throwing.

To examine the possibility of an electrical polyspermy block in the mouse, we recorded the electrophysiological properties of zona-free mouse eggs during fertilization. Starting from an unfertilized value of -41 +/- 4 mV (SD), the membrane potential undergoes an oscillation (seen in 8 of 11 records) of 4 +/- 1 mV in amplitude, starting 7 +/- 5 min after insemination, and lasting about 1 min. However, except for this small oscillation, the membrane potential is constant during the 60 min following insemination; the average range (11 +/- 4 mV) is not significantly different from that which is observed in 60-min recordings from unfertilized eggs. These results indicate that the polyspermy block which is established during this period (D. P. Wolf, 1978, Dev. Biol. 64, 1-10) is not electrically mediated. Consistent with this finding, reduction of the sodium or calcium concentration in the external medium does not induce polyspermy. As a consequence of fertilization, the resistance of the egg membrane decreases from 96 +/- 34 to 44 +/- 15 M omega; this change accompanies the voltage oscillation.

1. Intracellular pH (pHi) was measured in crab muscle fibres using pH-sensitive micro-electrodes. The mean stable pHi was 7.19 +/- 00.2 (S.E. of mean) and the corresponding mean membrane potential was -64.6 +/- 0.4 mV (S.E. of mean) at an external pH of 7.5. 2. The effects on pHi of replacing 20% (100 mM) of the external NaCl by the Na salts of various anions were examined. The anions of weak acid (pK'a greater than 4.5) caused large internal acidifications. The anions of strong acids (pK'a less than 2.6) caused little or no change in pHi. The anions of acids with an intermediate pK'a had varied effects on pHi. In particular salicylate (pK'a = 2.97) was found to cause a large fall in pHi. 3. Increasing the external pH reduced the effects of the anions of weak acids on pHi. It is argued that these effects are the result of the entry and subsequent dissociation of undissociated acid molecules. 4. The results with propionate were quantified by comparing them with the effects of 5% CO2 and were found to be smaller than expected. It is suggested that this is the result of substantial membrane permeability to the propionate anion.