スポーツ医学およびドーピング研究ジャーナル

A few studies have evaluated swaying motion of the body in the seated posture; however, these studies did not evaluate motion sickness caused by watching movies, traveling, etc. This study aimed to analyze stabilograms recorded while the individuals were seated. Stabilometry was performed on 7 healthy male subjects (age, 21–22 years) in the seated position 5 min before, and at 5-min intervals from 5 to 60 min after alcohol load. Alcohol caused a decrease in the cerebellar equilibrium function that controls the vestibulospinal reflex. We adjusted the degree of simulative effect on the human equilibrium function. The stabilograms of the test subjects were analyzed according to the area of sway, total locus length, and total locus length per unit area. We found that significant alcohol-induced changes in the sway values in the seated posture were similar to those in the upright posture.

The purpose of the present study was to examine the heart rate responses during small-sided games with different number of players. Sixteen professional soccer players were evaluated for body fat (%) using the skin fold thickness at three sites, VO2 max and running velocity at the lactate threshold using an incremental treadmill protocol. %HRmax was measured during four-, five-, six-, seven-, and eight-a side soccer games. The four-a-side game showed significantly (p<0.05) higher %HRmax in comparison to the other small-sided games. On the other hand, the %HRmax of the eight-a-side game was significantly lower (p<0.05) than three-, four-, five-, six-, and seven-a-side game. The intensity of small-sided games decreases as the number of players increase. The monitoring of heart rate during small-sided games combined with laboratory VO2 max tests is a possible way to define target training intensity zones.

Knee injuries are common in sport competitions. Risks of injuries can be significantly lowered by warm-up exercise prior to intense activity. This study aimed to determine simultaneously the long-term effect of competitive volleyball training and short-term effect of a warm-up exercise on passive kinematics and musculo-articular impedance of the knee joint. Twelve professional volleyball players (mean age 23.8 ± 3.9 years, weight 71.5 ± 7.1kg and height 1.75 ± 0.07m) and 12 moderately active subjects (mean age 20.2 ± 1.1 years, weight 63.2 ± 9.6 kg and height 1.63 ± 0.05 m) participated in the study. Passive knee joint kinematics (number of oscillations, start and end angles, total duration of oscillations, first four peak flexion angles, first peak extension angle, period of the first three cycles, plateau amplitude, amplitude of first flexion and extension, Flexion and Extension Relaxation Indexes), stiffness and viscosity were investigated using a leg drop pendulum test performed before and after a warm-up exercise consisting of a 10-minute treadmill running. Results showed no effect of competitive volleyball training background on knee joint kinematics, stiffness and viscosity. However, in the moderately active subjects, amplitude of the first flexion and Flexion Relaxation Index were significantly higher after the running exercise than before, reflecting greater musculo-articular compliance of the knee after the warm-up compared to volleyball players. In conclusion, no change in the stiffness of the knee in volleyball players could be beneficial to the practice of volleyball since insufficient lower limb stiffness may destabilize joint motion and increase the incidence of soft tissue injuries.

The purpose of this study was to determine if Critical Power (CP) and Anaerobic Work Capacity (AWC) could be estimated from a single, all-out test of less than 3-min. Twenty-eight subjects (mean ± SD: age 23.3 ± 3.3 years, body mass 71.6 ± 16 kg) performed an incremental cycle ergometer test to exhaustion to determine peak oxygen consumption rate and heart rate peak. The 3-min all-out test was used to determine the criterion and six estimated values of CP and AWC. The criterion critical power (CP180) and anaerobic work capacity (AWC180) values were determined from the 3-min all-out test and were expressed as 30-s averages (155-180-s). The six estimated CP and AWC values were calculated from 30-s averages at decreasing 10-s intervals from 145 to 170-s (CP170 and AWC170), 135 to 160-s (CP160 and AWC160), 125 to 150-s (CP150 and AWC150), 115 to 140-s (CP140 and AWC140), 105 to 130-s (CP130 and AWC130), and 95 to 120-s (CP120 and AWC120). Mean differences, total error, constant error, standard error of the estimate, and correlations were used to compare the criterion to the estimated CP and AWC values. The results of the present study indicated that 150-s was the shortest test duration that resulted in non-significant differences between the criterion (CP180 and AWC180) and estimated CP (CP150) and AWC (AWC150) values. The subsequent validation analyses showed that there were close agreements for the estimated CP150 and AWC150 versus the criterion (CP180 and AWC180) values. Therefore, the current findings indicated that estimates of CP and AWC were not affected by shortening the test by 30-s. Reducing the length of the test to 2.5 minutes provides a less strenuous, yet valid protocol for estimating CP and AWC.

Salmeterol is a long-acting beta2-agonist, which is on the WADA prohibited list, but can be used by athletes in therapeutic doses by inhalation. The prohibited list, however, contains no urinary threshold for salmeterol, which gives athletes the opportunity to inhale unlimited doses of salmeterol. In doping controls, metabolites may be used as markers for misuse of substances. No studies have determined urine concentrations of α-hydroxysalmeterol, the metabolite of salmeterol. Furthermore, the metabolism and excretion of salmeterol may vary between asthmatics and nonasthmatics. We determined the serum and urinary concentrations of salmeterol and its metabolite α-hydroxysalmeterol after inhalation of 100 μg salmeterol in ten asthmatics and ten non-asthmatics. Blood samples were collected at baseline and ½, 1, 2, 3, 4 and 6 hours after the administration of salmeterol. Urine samples were collected at baseline and 4, 8 and 12 hours after administration. The urinary concentration of salmeterol following enzymatic hydrolysis of the glucuronide fraction was 0.38 ± 0.26 ngmL-1 in asthmatics and 0.38 ± 0.22 ngmL-1 in non-asthmatics, 4 hours after inhalation. The highest median serum concentration (Cmax) was 0.07 ± 0.03 ngmL-1 in asthmatics after 30 minutes (Tmax) and 0.06 ± 0.03 ngmL-1 in non-asthmatics. No statistical differences were found in Cmax or Tmax of salmeterol between asthmatics or non-asthmatics in neither the serum nor urine samples. The highest median urinary concentration of α-hydroxysalmeterol following enzymatic hydrolysis of the glucuronide fraction was 2.86 ± 1.75 ngmL-1 in asthmatics, 4 hours after inhalation of salmeterol. In non-asthmatics, it was 2.73 ± 2.08 ngmL-1. The asthmatics had a significantly (p<0.05) higher concentration after 12 hours compared with non-asthmatics. In doping control, α-hydroxysalmeterol may be a more suitable marker for excessive use of inhaled salmeterol, due to its higher concentration in urine.

Acute soft-tissue lesions and chronic overuse injuries in the sports medicine field are very frequent and in most cases, difficult to treat. Tissue repair in musculoskeletal lesions is often too slow and sometimes incomplete for a given athlete. The fastest, most complete recovery is of primary importance, and keeping the delay until return-to- field as brief as possible, a priority. Many bioactive proteins and growth factors amongst others influence healing processes. Administration of Platelet Rich Plasma enables the production, from the patient’s own blood, of natural, high concentrations of autologous growth factors. Basic research and animal studies are promising, but evidence- based studies examining the treatment of human musculoskeletal lesions by Platelet Rich Plasma are still lacking. Nevertheless, such treatment is increasingly used in sports medicine clinical practice and much is expected of growth factor injections. The aim of this non exhaustive review is to analyze the existing literature published in the fields of sports medicine. The results of this analysis do not permit us to recommend the systematic and generalized use of Platelet Rich Plasma injections in the management of sport injuries. Nevertheless, a few promising results have to be mentioned, but high-quality studies are needed to provide scientific evidence about these injections’ effectiveness.

Introduction: The term joint hypermobility syndrome (JHS) was adopted after clinicians became aware of the myriad of symptoms associated with this multisystemic condition. JHS is an inherited disorder of connective tissues affecting the musculoskeletal and visceral systems which may contribute to a reduction in health related physical fitness. Pain associated with JHS may be influenced by hypermobility and biomechanical dysfunction. Biomechanical dysfunction observed in patients with JHS may be as a result of impaired motor control and in particular developmental coordination disorder (DCD). DCD (described in the literature utilising the terms clumsy child syndrome; perceptual motor dysfunction; dyspraxia) is a neurodevelopmental condition characterised by coordination difficulties affecting function. The objective of this review is to examine the association between hypermobility, JHS, motor control impairment and DCD.

Methods and data sources: EMBASE, MEDLINE, CINAHL, ASSIA, PsychARTICLES, SPORTDiscus and PsycINFO from 1989 - 2009. Research articles written in English and peer reviewed were included.

Results: Five research papers were identified. The studies employed a variety of methodologies and assessment tools for reporting joint hypermobility, JHS, motor delay, motor impairments and DCD. All five studies reported on children between the ages of six months and 12 years. Three out of four studies reported on association between impaired motor development, motor delay and joint hypermobility. There was no consensus as to whether motor delay, impaired motor development and joint hypermobility continued as the child matured. One study ascertained that children with JHS reported similar functional difficulties as children with DCD.

Conclusion: There was a paucity of literature relating to an association between joint hypermobility, JHS, impaired motor control, motor delay and DCD in children, there was no literature pertaining to adults. This association requires further exploration if professionals are to understand, nurture and manage those reporting these associated conditions.