Effects of a barefoot intervention programme on the landing kinetics and kinematics of netball players

Jaiyesimi, Boluwaji Gbenga (2018-12)

Thesis (PhD(SportSc))--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: Effective landings, as a component of movement tasks in many sports, have a significant role during ground contact and subsequent kinetic chain intersegmental interactions. Landings are frequently performed tasks in sports to manipulate skills, maximise mechanical functions of the body and to possibly avoid injury. The rationale of biomechanical studies on landing in netball focuses on the reduction of risk of lower extremity injuries and enhance performance. The trauma of injury to a female athlete ranges from immobility, disengagement from the team to psychophysiological stress and physical deterioration. The primary aim of the study was to determine the acute differences in landing kinetics and kinematics between barefoot and shod conditions in netball players. The secondary aim was to determine effect of a six-week barefoot training intervention on landing biomechanics in netball players. The experimental design adopted for the study was a pretest-posttest randomized groups design. Thirty netball players were recruited for the study and randomly allocated into an experimental (EXP) (n = 15) or a control group (CON) (n = 15). The players performed jump-landing tasks (single-leg drop landing right and left) (SLR and SLL), a drop vertical jump (DVJ) and a stop-jump performance task (SJPT) in barefoot (BF), and shod (SH) conditions. The intervention for the study spanned a 6-week period with 18 training sessions over this period. Ground reaction forces, time to peak ground reaction forces and shock attenuation were considered for kinetic variables while impact peak acceleration, initial contact angles, peak angles and range of motion were considered for kinematic variables. A 3D force plate (sampled at 1000 Hz) was used to capture force data while a wireless inertial motion capture system (sampled at 200 Hz, filtered with Butterworth 60 Hz low-pass), was used to capture kinematic data. The Subjective evaluation of the Landing Error Scoring System (LESS), Modified Lower Limb Comfort Index (mLLCI) and barefoot activity experience was adopted for qualitative assessment of the study. Mean, standard deviation, standard error of mean, and percentage differences were used in the descriptive analysis while Chi-square, independent t-tests and a mixed model ANOVA were used in the inferential analysis. The results showed a non-significant reduction in peak resultant force and vertical ground reaction forces for the jump-landing tasks in SH condition. The mediolateral ground reaction force was significantly lower in BF condition for some of the jump-landing tasks (SLL p = 0.02; DVJ p = 0.03). It was further shown that sagittal plane kinematics increased at initial contact in BF condition but decreased at peak angle. The frontal plane kinematics increased in BF more than SH conditions at initial contact but decreased at peak angle. The EXP (p = 0.00) and CON groups (p = 0.00) had significant changes in knee shock attenuation after the intervention. However, the CON group had more shock attenuation at the knee and ankle during the jump-landing tasks. The feedback of subjective experience of barefoot activities after the intervention showed that the negative experience of injury risks and significant others did not outweigh the positive perception of neuromuscular benefits and other related factors. In conclusion, BF training could form part of training modalities implemented to enhance safe and effective landings. Coaches need to be educated on the implementation of an injury prevention programme, including emphasis on effective landings, to possibly reduce the incidence of lower limb injuries in netball. Keywords: Barefoot, kinetics, kinematics, shock attenuation, impact peak acceleration

AFRIKAANSE OPSOMMING: Effektiewe landing, as ‘n komponent van baie sportbewegingstake, speel ‘n belangrike rol gedurende grondkontak en die gevolglike intersegmentale interaksies van die kinetiese ketting. Landing is ‘n bewegingstaak wat dikwels uitgevoer word by die manipulering van vaardighede, om meganiese funksies van die liggaam te maksimaliseer en om moontlike beserings te voorkom.Die rasionaal vir studies in verband met landing in netball is om ‘n moontlike bydrae te lewer om beseringsrisiko van die onderste ledemate te verinder en prestasie te verbeter. Die trauma as gevolg van beserings by vroue-atlete wissel van immobiliteit, verwydering van die span tot sielkundig-fisiologiese stress en fisieke agteruitgang. Die primêre doel was om te bepaal of daar akute verskille is tussen kaalvoet- en skoenkondisies tydens landings by die netbalspelers. Die sekondêre doel van die studie was om die effek van ‘n ses-weke kaalvoetintervensie op die landingsbiomeganika van netbalspelers te bepaal. Die studie-ontwerp was ‘n pre- posttoetsing met lukrake groepe. Dertig netbalspelers is vir die studie gewerf en lukraak in ‘n eksperimentele- (EKS) (n = 15) en ‘n kontrolegroep (KON) (n = 15) ingedeel. Die spelers het spring-landtake (enkelbeen aftree-landing links en regs EAL, EAR), vertikale spring en valsprong (VS), en ‘n stop-springtaak (SST) uitgevoer in kaalvoet- (KV) en skoen- (SK) kondisies. Die intervensie was oor ‘n periode van ses weke met 18 oefensessies in die tydperk. Grondreaksiekragte, tyd tot piek reaksiekragte en skokvermindering is ingesluit as kinetiese veranderlikes, terwyl peik-impak versnelling, aanvanklike kontakhoeke, piekhoeke en omvang van beweing as kinematiese veranderlikes ingesluit is. ‘n 3D kragplatform (1000 Hz) is gebruik om die kragdata op te neem, terwyl ‘n koordlose inersie bewegingssisteem (200 Hz; gefiltreer met Butterworth 60 Hz lae-deurgang), gebruik is om die kinematiese date te versamel. Kwalitatiewe data is genereer deur middel van die subjektiewe Landingsfoutsisteem, die Aangepaste Onderste Ledemaat Gemaksindeks en terugvoer oor die kaalvoetondervinding. Gemiddeldes, standaardafwyking, standardmetingsfout en persentasie verskille is gebruik in die beskrywende statistiek, terwyl Chi-kwadraat, onafhanklike T-toetse en ‘n gemengde model ANOVA gebruik is vir inferensiële analises. Resultate het ‘n afname in die piek resultante krag en vertikale grondreaksiekragte met die spring-land take in SK getoon. Die medio-laterale grondreaksiekrag was laer by sommige van die spring-landtake in KV (EAL p = 0.02; VS p = 0.03).Verder was daar ‘n toename in die sagittale vlak kinematika met aanvanklike kontak in KV, maar dit het verminder met piekhoek. Frontale vlak kinematika het meer in KV toegeneem as in SK met aanvanklike kontak, maar het verminder by piekhoeke. Die EKS (p = 0.00) en die KON (p = 0.00) het beduidende veranderinge in die knee en enkelskokvermindering na die intervensie getoon. Die KON het egter meer skokvermindering by die knie en enkel gedurende spring-landtake gehad. Die terugvoer oor die subjektiewe ervaring van die kaalvoet-aktiwiteite wys dat die ervaring van beseringsrisiko en beduidende ander nie die positiewe persepsie van neuromuskulêre voordele en verbandhoudende faktore negatief beinvloed het nie. Ten slotte, KV kan deel vorm van oefenmodaliteite wat toegepas word vir veilige en effektiewe landings. Afrigter behoort opgelei te word om beseringsvoorkomingsprogramme te implementer wat ook fokus op die leer van effektiewe landingspatrone om moontlik beserings aan die onderste ledemate te verminder. Sleutelwoorde: Kaalvoet, kinetika, kinematika skokvermindering, impak piekversnelling

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