Energy Cost of Continuous Shuttle Running: Comparison of 4 Measurement Methods.

Ciprandi, D, Lovecchio, N, Piacenza, M, Limonta, E, Esposito, F, Sforza, C, Zago, M. Energy cost of continuous shuttle running: Comparison of 4 measurement methods. J Strength Cond Res 32(8): 2265-2272, 2018-Assessing runs with frequent turns (shuttle run) is a viable option to evaluate the energy cost associated with sport-specific high-intensity intermittent activities. To date, no study investigated the extent to which the computation of energy cost of exercise is affected by the following factors: procedure and duration of oxygen uptake measurement during exercise, oxygen uptake measurement during recovery, estimation of the anaerobic alactic contribution, consideration of respiratory exchange ratio (RER) in the computation, and exercise intensity. Therefore, the aim of the current study was to determine whether these factors may lead to different estimations of the energy cost of locomotion. Twenty-six healthy young men participated in two 5-m shuttle-run trials at an average speed of 50 and 75% of their maximal aerobic velocity, respectively. Oxygen uptake and lactate concentration were measured before, during, and after the trials. Results revealed that different methods of computing the energy cost of 5-m shuttle run returned significantly different results, in particular at high intensity levels. The largest significant difference found between methods was lower than 10%. This suggests that for the most accurate computation of the workload, the contribution of the anaerobic alactic mechanisms and the influence of the RER cannot be neglected. These findings might help sport scientists and conditioning trainers in identifying the exercise conditions in which including all the metabolic components are required for an accurate computation of athletes' energy expenditure. In turn, exercise conditions would be defined where the computation could be conveniently simplified without worsening results reliability.

Dribbling determinants in sub-elite youth soccer players.

Dribbling speed in soccer is considered critical to the outcome of the game and can assist in the talent identification process. However, little is known about the biomechanics of this skill. By means of a motion capture system, we aimed to quantitatively investigate the determinants of effective dribbling skill in a group of 10 Under-13 sub-elite players, divided by the median-split technique according to their dribbling test time (faster and slower groups). Foot-ball contacts cadence, centre of mass (CoM), ranges of motion (RoM), velocity and acceleration, as well as stride length, cadence and variability were computed. Hip and knee joint RoMs were also considered. Faster players, as compared to slower players, showed a 30% higher foot-ball cadence (3.0 ± 0.1 vs. 2.3 ± 0.2 contacts · s(-1), P < 0.01); reduced CoM mediolateral (0.91 ± 0.05 vs. 1.14 ± 0.16 m, P < 0.05) and vertical (0.19 ± 0.01 vs. 0.25 ± 0.03 m, P < 0.05) RoMs; higher right stride cadence (+20%, P < 0.05) with lower variability (P < 0.05); reduced hip and knee flexion RoMs (P < 0.05). In conclusion, faster players are able to run with the ball through a shorter path in a more economical way. To effectively develop dribbling skill, coaches are encouraged to design specific practices where high stride frequency and narrow run trajectories are required.

Kinematic traits of an elite paralympic karateka: a case report.

Karate is a martial art that includes striking, kicking and punching techniques, and requires high levels of functional skills. Karate counts millions of practitioners worldwide and it is also spreading in Paralympic competitions: there is a need for accurate categories definition for disabled athletes. The aim of the current study was to present kinematic data of an elite Paralympic karateka, in comparison with able-bodied athletes, to promote a better classification within the discipline, based on objective evaluations of physical impairments. A male black belt Paralympic karateka (age: 36 years; body weight: 75.5 kg; height: 173 cm) with lower limbs impairments was evaluated. He performed a standardized sequence of movements (kata) from Shotokan karate. Joints and center-of-mass kinematics were collected with an optoelectronic motion capture system and compared with those obtained in two groups of able-bodied (Masters and Practitioners) athletes from a previous study. The sequence performed by the karateka lasted longer than in both able-bodied groups. Center of mass velocity and acceleration lowered in comparison with Masters. Knees range of movement and peak angular velocity were similar to Practitioners but lower than Masters. We concluded that physical impairments negatively affected the function of lower limbs in the Paralympic athlete, as fundamental skills in karate elite performance (dynamic balance control and joint angular velocity) were lower.

Influence of energy cost and physical fitness on the preferred walking speed and gait variability in elderly women.

Typically gait speed decreases and gait variability increases in elderly. The aim of this study was to define the influence of energy cost of walking on gait speed and of health-related physical fitness on gait variability. Thirty healthy young and older women were recruited in the study. Energy cost of walking (NetCW) was analyzed with indirect calorimetry while a kinematic analysis was performed with an optoelectronic system to calculate gait variability (GV) during treadmill walking at different speeds. Gait speed was defined as the preferred walking speed (PWS) of the subject and health related physical fitness (HRPF) comprised body fat, strength, flexibility, and cardiorespiratory fitness. In healthy elderly women, the coefficient of variation of step width was found to be a better indicator of GV than stride time, stride length and double support coefficients of variation. GV was not affected by age allowing a high PWS. Furthermore, significant associations, adjusted for age, body mass index and number of falls, were identified neither between NetCW and the PWS, nor between HRPF and GV; only a significant association was found between hand-grip strength and gait stability. Findings highlighted the importance to evaluate hand-grip strength as an indicator of gait efficiency.

Reanimation of the paralyzed lids by cross-face nerve graft and platysma transfer.

Alterations of facial muscles may critically humper patients' quality of life. One of the worst conditions is the reduction or abolition of eye blinking. To prevent these adverse effects, surgical rehabilitation of eyelid function is the current treatment choice. In the present paper, we present a modification of the technique devised by Nassif to recover lids from long-standing paralysis. In our modification, the upper lid is rehabilitated by a platisma graft innervated by the contralateral facial nerve branches using a cross-face sural nerve graft. The lower lid is pulled upward by a fascia lata string suspension. Fourteen patients with unilateral facial paralysis were operated on consecutively. For each patient, two sets of frontal photographs with open and closed eyes were available, before and after the surgical rehabilitation. On average, eyelid lumen with closed eyes decreased by 2.6 mm (SD 2.4) after surgical rehabilitation (37% of the initial value). With open eyes, the decrement was 1.5 mm (SD 1.6, 15%). The modifications were highly significant (p < 0.01), with very large effect sizes. Reanimation of the paralyzed eye by mean of cross-face nerve graft followed by platisma neurotization can restore natural eyelid closure and blink reflex.

Gait analysis of young male patients diagnosed with primary bladder neck obstruction.

Primary bladder neck obstruction (PBNO) represents an inappropriate or inadequate relaxation of the bladder neck during micturition. Based on the observation of an increased rate of postural imbalances in male patients with PBNO, we hypothesized a possible role of an unbalanced biomechanics of the pelvis on urethral sphincters activity. Our aim was to identify kinematic imbalances, usually disregarded in PBNO patients, and which could eventually be involved in the etiopathogenesis of the disease. Seven male adult patients (39.6±7.1years) were recruited; in all patients, PBNO was suspected at bladder diary and uroflowmetry, and was endoscopically confirmed with urethroscopy. Participants gait was recorded with a motion capture system (BTS Spa, Italy) to obtain three-dimensional joint angles and gait parameters. Multivariate statistics based on a Principal Component model allowed to assess the similarity of patients' gait patterns with respect to control subjects. The main finding is that patients with PBNO showed significant discordance in the observations at the ankle and pelvis level. Additionally, 6/7 patients demonstrated altered trunk positions compared to normal curves. We suggest that the identified postural imbalances could represent the cause for an anomalous activation of pelvic floor muscles (hypertonia). The consequent urinary sphincters hypercontraction may be responsible for the development of voiding dysfunction in male patients with no significant morphological alterations. Results reinforced the hypothesis of an etiopathogenetic role of postural imbalances on primary bladder neck obstruction in male patients.

Study of the association between gait variability and physical activity.

BACKGROUND: Gait variability can be considered an indirect measure of gait stability, in particular regarding temporal or spatial variability assessment. Physical activity, such as walking, is advised for the elderly and can be improved by gait stability. The aim of this study was to investigate the associations between gait stability and physical activity in women of different age ranges. METHODS: Forty-two healthy women of different age ranges (18-40 yrs. and 65-75 yrs.) were recruited in the study. To assess physical activity, the subjects wore a multi-sensor activity monitor for a whole week, inferring the time spent in moderate to vigorous physical activity (MVPA). MVPA were analysed in bouts of at least 10 subsequent minutes (MVPAbouts) and in overall minutes (MVPAtot). A kinematic analysis was performed with an optoelectronic system to calculate gait variability - expressed as standard deviation (SD) and coefficient of variability (CV) of step width, stride length, stance and swing time (during treadmill walking at different speeds). RESULTS: Elderly women, with high walking speed (5 km/h), and moderate step width variability (CV = 8-27%), met the recommended levels of physical activity (MVPAtot and MVPAbouts). Furthermore, gait variability, adjusted for age and number of falls, was significantly and negatively associated with MVPAtot only at 3.5 km/h, and with MVPAbouts only at 4 km/h. CONCLUSIONS: In a population of healthy elderly women, gait variability was significantly and negatively associated with the level of physical activity. Healthy elderly women, with moderate gait variability (step width variability), and high preferred walking speed, seem to be able to meet the recommended levels of physical activity.

Primary bladder neck obstruction may be determined by postural imbalances.

Primary bladder neck obstruction (PBNO) is a frequent under-investigated urological condition in which the bladder neck fails to open adequately during voiding. In the majority of cases no known etiological factor can be found. In this study we propose a new hypothesis to explain the origin of the disease in young male patients with no neurological disorders. We suggest a possible role of an unbalanced biomechanics of the pelvis on urethral sphincters activity and on functional bladder capacity. To support the proposed hypothesis, we present pilot gait analysis data of young male patients with primary bladder neck obstruction.

Dynamic balance in elite karateka.

In karate, balance control represents a key performance determinant. With the hypothesis that high-level athletes display advanced balance abilities, the purpose of the current study was to quantitatively investigate the motor strategies adopted by elite and non-elite karateka to maintain balance control in competition. The execution of traditional karate techniques (kihon) in two groups of elite Masters (n = 6, 31 ± 19 years) and non-elite Practitioners (n = 4, 25 ± 9 years) was compared assessing body center of mass (CoM) kinematics and other relevant parameters like step width and angular joint behavior. In the considered kihon sequence, normalized average CoM height was 8% lower (p < 0.05), while CoM displacement in the horizontal direction was significantly higher in Masters than in Practitioners (2.5 vs. 1.9 m, p < 0.05), as well as CoM average velocity and rms acceleration (p < 0.05). Step width was higher in Masters in more than half of the sequence steps (p < 0.05). Results suggest that elite karateka showed a refined dynamic balance control, obtained through the increase of the base of support and different maneuvers of lower limbs. The proposed method could be used to objectively detect talented karateka, to measure proficiency level and to assess training effectiveness.