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.

Three-dimensional motion analysis of facial movement during verbal and nonverbal expressions in healthy subjects.

Functional impairments of facial expressions alter the quality of life and their quantitative analysis is key to describing and grading facial function and dysfunction. The aim of this investigation was to quantify 3D lip movements in a group of healthy young subjects. Lip movements during five repetitions of common and random sequences of vowels and nonverbal expressions were recorded using an optoelectronic 3D motion analyzer. The mean maximum displacement of facial landmarks was used to compute 3D unilateral mobility and the symmetry indices (SI) separately for each sex. Facial mobility was significantly greater during open-mouth than closed-mouth smiles. Facial movement among the subjects was largest during articulation of the vowel /a/ and smallest for /i/. Lips were pursed with a SI very close to 95%, while smiles were slightly more asymmetric. The vowel /a/ was articulated with significantly greater symmetry than /e/, /i/ and /u/. The outcomes suggest that the proposed method characterized normal facial animations satisfactorily, so it could be a useful tool for assessing patients with facial lesions and dentofacial deformities. Patient assessment would profit from this quantitative approach, which would reduce discrepancies among several clinical examinations. Clin. Anat. 29:991-997, 2016. © 2016 Wiley Periodicals, Inc.

Double-powered free gracilis muscle transfer for smile reanimation: A longitudinal optoelectronic study.

The choice of the motor donor nerve is a crucial point in free flap transfer algorithms. In the case of unilateral facial paralysis, the contralateral healthy facial nerve can provide coordinated smile animation and spontaneous emotional expression, but with unpredictable axonal ingrowth into the recipient muscle. Otherwise, the masseteric nerve ipsilateral to the paralysis can provide a powerful neural input, without a spontaneous trigger of the smile. Harvesting a bulky muscular free flap may enhance the quantity of contraction but esthetic results are unpleasant. Therefore, the logical solution for obtaining high amplitude of smiling combined with spontaneity of movement is to couple the neural input: the contralateral facial nerve plus the ipsilateral masseteric nerve. Thirteen patients with unilateral dense facial paralysis underwent a one-stage facial reanimation with a gracilis flap powered by a double donor neural input, provided by both the ipsilateral masseteric nerve (coaptation by an end-to-end neurorrhaphy with the obturator nerve) and the contralateral facial nerve (coaptation through a cross-face nerve graft: end-to-end neurorrhaphy on the healthy side and end-to-side neurorrhaphy on the obturator nerve, distal to the masseteric/obturator neurorrhaphy). Their facial movements were evaluated with an optoelectronic motion analyzer. Before surgery, on average, the paretic side exhibited a smaller total three-dimensional mobility than the healthy side, with a 52% activation ratio and >30% of asymmetry. After surgery, the differences significantly decreased (analysis of variance (ANOVA), p < 0.05), with an activation ratio between 75% (maximum smile) and 91% (maximum smile with teeth clenching), and <20% of asymmetry. Similar modifications were seen for the performance of spontaneous smiles. The significant presurgical asymmetry of labial movements reduced after surgery. The use of a double donor neural input permitted both movements that were similar in force to that of the healthy side, and spontaneous movements elicited by emotional triggering.

Effect of Leg Dominance on The Center-of-Mass Kinematics During an Inside-of-the-Foot Kick in Amateur Soccer Players.

Soccer kicking kinematics has received wide interest in literature. However, while the instep-kick has been broadly studied, only few researchers investigated the inside-of-the-foot kick, which is one of the most frequently performed techniques during games. In particular, little knowledge is available about differences in kinematics when kicking with the preferred and non-preferred leg. A motion analysis system recorded the three-dimensional coordinates of reflective markers placed upon the body of nine amateur soccer players (23.0 ± 2.1 years, BMI 22.2 ± 2.6 kg/m2), who performed 30 pass-kicks each, 15 with the preferred and 15 with the non-preferred leg. We investigated skill kinematics while maintaining a perspective on the complete picture of movement, looking for laterality related differences. The main focus was laid on: anatomical angles, contribution of upper limbs in kick biomechanics, kinematics of the body Center of Mass (CoM), which describes the whole body movement and is related to balance and stability. When kicking with the preferred leg, CoM displacement during the ground-support phase was 13% higher (p<0.001), normalized CoM height was 1.3% lower (p<0.001) and CoM velocity 10% higher (p<0.01); foot and shank velocities were about 5% higher (p<0.01); arms were more abducted (p<0.01); shoulders were rotated more towards the target (p<0.01, 6° mean orientation difference). We concluded that differences in motor control between preferred and non-preferred leg kicks exist, particularly in the movement velocity and upper body kinematics. Coaches can use these results to provide effective instructions to players in the learning process, moving their focus on kicking speed and upper body behavior.

Facial reanimation with masseteric to facial nerve transfer: a three-dimensional longitudinal quantitative evaluation.

Facial paralysis is a severe pathological condition, negatively affecting patients' quality of life. The altered tone and mobility of the mimetic musculature provoke both functional and morphological deficits. In the present study, we longitudinally measured facial movements in 14 patients (21-69 years) affected by unilateral facial paralysis not lasting longer than 23 months. The patients were analyzed before and after surgical masseteric to facial nerve neurorrhaphy. Examinations were performed at least 3 months after they had clinically started to regain facial mimicry. The displacement of selected facial landmarks was measured using an optoelectronic three-dimensional motion analyzer during: maximum smile without clenching (pre- and postsurgery), maximum smile by clenching on their posterior teeth (only postsurgery), and spontaneous smile (recorded during the vision of a funny video in both examinations). Before facial surgery, in all smiles facial landmarks moved more in the healthy than in the paretic side; after surgery, the differences decreased for both reduction of the healthy-side motion, and increment of the paretic-side motion (motion ratio before 52%, after 87%, p < 0.05, Students' t-test). The ratio between the paretic and healthy-side total motion (asymmetry) did not modify for maximum and spontaneous smiles, but significantly increased for the maximum smiles made with teeth clenching (asymmetry before 32%, after 11%, p < 0.001). Spontaneous smiles were recorded only in a subset of patients, but their execution was modified by surgery, with more symmetrical movements of the rehabilitated-side landmarks (asymmetry before 33%, after 10%), and reduced motion of the healthy-side ones (motion ratio before 51%, after 83%). In conclusion, the significant asymmetry in the magnitude of facial movements that characterized the analyzed patients before surgery reduced after surgery, at least in those facial areas interested by the masseteric to facial nerve reanimation.