LOW BACK PAIN: BIOMECHANICS ANALYSIS AND PREVENTION

Epidemiological studies have shown that lower back pain from golf represent 25% of all golf related injuries. A review of the literature shows that the etiology is pluri-factorial, with general and specific risk factors. For the average players and the elite players, the mechanical loadings on the lumbar spine must be analyzed during all the golf swing. The specific risk factors, as range of motion restriction, abnormal muscle recruitment, excessive X-factor, important right side bending with high velocity lumbar rotation (crunch factor) are essential elements to be considered in a prevention strategy. Golf can aggravate pre-existing low back pain, especially in a context of overuse, without correct warm-up and with important golf swing technical fault but golf could also be an efficient treatment when it is practiced in good conditions

Antimicrobials in a rabbit semen extender: effects on reproduction

[EN] The use of fluoroquinolone antibiotics was legally restricted by the European Commission in March 2019. Since the extender for rabbit semen Galap® contained this antibiotic, it became necessary to modify it. The purpose of this study was to search for another molecule, based on its antimicrobial activity and also on the conservation, motility and fertility of semen diluted with the new extender. Several bacterial strains were isolated from 10 poor-quality ejaculates, including Enterococcus spp., Staphylococcus aureus and Proteus spp. They were then tested for antimicrobial susceptibility. Out of 15 antibiotics evaluated, gentamicin was the one targeting such bacteria. In vivo tests were then carried out to assess the effects of this antibiotic change on sperm parameters. Up to 26 pools of good quality semen (total motility >70%) were diluted in original Galap® or in this extender with gentamicin. Ejaculates were analysed on the day (D) of collection and up to 6 d of storage at +17°C. After 24 h storage, the motility in the new extender was reduced by 7.7% compared to the original; this decrease did not worsen by storing. After 6 d of storage, no difference between the two media was detected. A total of 360 females were then inseminated with pools of 4 to 5 good quality semen diluted 1:10 in both extenders, following the routine protocol of rabbit semen processing centres. There was no difference in female fertility or prolificacy between both formulations. In conclusion, these preliminary results suggest that the addition of gentamicin to this extender is useful and also has no adverse effect on fertility or prolificacy.This study was supported by IMV TechnologiesRouillon, C.; Camugli, S.; Carion, O.; Echegaray, A.; Delhomme, G.; Schmitt, E. (2022). Antimicrobials in a rabbit semen extender: effects on reproduction. World Rabbit Science. 30(4):295-308. https://doi.org/10.4995/wrs.2022.1713229530830

LOWER BODY KINEMATICS AND MUSCLE ACTIVITY DURING EXERCICES IN 3D MOTORIZED ROTATING PLATFORM. IN-VIVO STUDY AND MODEL

The purpose of this study was to characterize muscle solicitations implied by the movement of a motorized rotating platform (MRP). Subjects performed five classical exercises on a MRP as part of lower limbs rehabilitation programs. EMG signals were recorded to quantify level and duration of activation of seven lower limbs muscles. Subject-specific musculoskeletal models were built and animated from kinematic recordings to estimate muscle lengths evolution. Results show that unipodal stance exercise was more demanding compared to bipodal ones. The characterization of solicitations imposed by MRP exercises could be useful for physiotherapists in order to help them to better select and configure exercises regarding to subject specificities, pathology and rehabilitation evolution

Contribution of vertical and horizontal components of ground reaction forces on global motor moment during a golf swing: a preliminary study

No abstract availabl

Biomechanical analysis of the golf swing: methodological effect of angular velocity component on the identification of the kinematic sequence

The golf swing is a complex whole-body motion for which a proximal-to-distal transfer of the segmental angular velocitiesfrom the pelvis to the club is believed to be optimal for maximizing the club head linear velocity. However, previous experimental resultsabout such timing (or kinematic sequence) are contradictory. Nevertheless, methods that were used in these studies differed significantly,in particular, those regarding the component of the angular velocity vector selected for the identification of the kinematic sequence.Hence, the aim of this study was to investigate the effect of angular velocity vector component selection on the identified kinematicsequence. Methods: Thirteen golfers participated in this study and performed driver swings in a motion capture laboratory. Seven meth-ods based on different component selection of segmental angular velocities (vector norm, component normal-to-sagittal, frontal, trans-versal and swing planes, segment longitudinal component and a method mixing longitudinal and swing plane components) were tested.Results: Results showed the critical influence of the component chosen to identify the kinematic sequence with almost as many kine-matic sequences as the number of tested methods for every golfer. Conclusion: One method seems to show the strongest correlation toperformance but none of them can be assessed as a reference method for the identification of the golf swing kinematic sequence. Re-garding the limited time lag between the different peak occurrences and the uncertainty sources of current materials, development ofsimulation studies would be more suitable to identify the optimal kinematic sequence for the golf swin

Effect of shoulder model complexity in upper-body kinematics analysis of the golf swing

The golf swing is a complex full body movement during which the spine and shoulders are highly involved. In order to determine shoulder kinematics during this movement, multibody kinematics optimization (MKO) can be recommended to limit the effect of the soft tissue artifact and to avoid joint dislocations or bone penetration in reconstructed kinematics. Classically, in golf biomechanics research, the shoulder is represented by a 3 degrees-of-freedom model representing the glenohumeral joint. More complex and physiological models are already provided in the scientific literature. Particularly, the model used in this study was a full body model and also described motions of clavicles and scapulae. This study aimed at quantifying the effect of utilizing a more complex and physiological shoulder model when studying the golf swing. Results obtained on 20 golfers showed that a more complex and physiologically-accurate model can more efficiently track experimental markers, which resulted in differences in joint kinematics. Hence, the model with 3 degrees-of-freedom between the humerus and the thorax may be inadequate when combined with MKO and a more physiological model would be beneficial. Finally, results would also be improved through a subject-specific approach for the determination of the segment lengths

Determination of the intervertebral spinal axial rotation in a golf player population: a preliminary study

No abstract availabl

Influence of the projection plane and the markers choice on the X-factor computation of the golf swing X-factor: a case study

Study of variability induced by the methology choice on the X-factor computation of the golf swing. Based on optoelectronic measurements. Variability of the choice of upper limb, plane of projection and instant of computation

Effect of Horizontal Ground Reaction Forces during the Golf Swing: Implications for the development of technical solutions of golf swing analysis

The swing is a key movement for golf. Its in-field performance could be estimated by embedded technologies, but often only vertical ground reaction forces (VGRF) are estimated. However, as the swing plane is inclined, horizontal ground reaction forces (HGRF) are expected to contribute to the increase of the club angular velocity. Thus, this study aimed at investigating the role of the HGRF during the golf swing. Twenty-eight golf players were recruited and performed 10 swings with their own driver club, in a motion analysis laboratory, equipped with a full body marker set. Ground reaction forces (GRF) were measured with force-plates. A multibody kinematic optimization was performed with a full body model to estimate the instantaneous location of the golfer’s center of mass (CoM). Moments created by the GRF at the CoM were investigated. Results showed that horizontal forces should not be neglected regarding to VGRF because of their lever arm. Analyzing golf swing with only VGRF appeared not enough and further technological developments are still needed to ecologically measure other components