Fast bowlers are especially prone to injury as they perform their bowling techniques repetitively at very high intensities. The fast bowling action in the past has been described as a highly explosive activity that produces high levels of stress and strain on the body. The aim of this study was to compile an injury profile of 46 fast bowlers aged 11 to 18, and to identify the associated risk factors for injury during an academy cricket season. A descriptive correlational research design was utilised. Subjects were selected according to age and fast bowling ability. These subjects were observed for one academy cricket season (March to November). Three testing sessions occurred during this time (T1, T2 and T3). Each subject completed two questionnaires: i) bowler history (at T1) and ii) injury history (at T1, T2, and T3). These assisted in grouping the subjects according to their responses into one of three injury classifications (uninjured = S1; injured but able to play = S2; injured and unable to play = S3). Anthropometric and postural data for the entire group of fast bowlers were also collected pre-season (T1). Physical fitness screenings were also conducted during each of the three testing sessions to establish any relationship between the fitness of each fast bowler and the occurrence of injuries. Additional factors assessed during the season were bowling techniques and bowling workload. Statistical significance was indicated by p-values less than .05 (p< .05), while practical significance was indicated by either Cohen’s d-values of 0.2 or better (d>0.2) for tests based on sample means or Cramer’s V for tests based on sample frequencies, the values of which depend on the applicable degrees of freedom. All fitness scores as well as bowling workload figures for each testing session were converted to standard T-scores and these in turn were summated to derive overall fitness and workload T-scores. ‘TT’ indicated the overall average score for the entire season. Changes in performances, bowling workload and injury status were analysed using ANOVA and ANCOVA. A regression analysis was also conducted to analyse the relationship between bowling workload and weeks incapacitated. This study found that hyperextension in the knees had the highest incidence of postural deviation injury (43 percent) followed by winged scapula (39 percent). Only 15 percent of the fast bowlers remained injury-free for the duration of the season, while 35 percent of the subjects were at some stage injured to such an extent that they were unable to play. The incidence of serious injury (S3) showed a statistical and moderate practical (V=0.23, d.f. ≥2) significant increase throughout the data collection period (4 percent at T1 to 30 percent at T3). The most common injury was to the knee (41 percent) followed by those to the lower back (37 percent). These injuries occurred mostly during test periods T2 and T3. The nature of injuries were predominantly strains and "other" which accounted for 39 percent of the injuries overall (TT) and had the highest reported incidence during the period T1 to T3. Sprains followed with an overall incidence of 14 percent. Less frequently reported injuries were tears, fractures, bruises and dislocations. The degree of severity of injuries was defined in terms of the number of weeks a player reported being incapacitated as a result of injury during the academy session. During midand end-season bowlers were on average incapacitated approximately one week out of every five due to injury. The statistics for the duration of the study translate to approximately one week incapacitated out of every seven weeks of play. When comparing the S1/S2 bowlers with the S3 group, the S1/S2 bowlers performed consistently better than the S3 bowlers in all the fitness variables tested. However no significant differences (p>.05) in either flexibility or muscle strength were observed. Of the risk factors analysed, bowling workload presented a statistically significant (p<.0005) increased risk for injury. A strong significant positive relationship (p<.0005, R²=.619) was found between weeks incapacitated and bowling workload, supporting the finding that increased bowling workloads show a linear relationship with the increase in the number of weeks incapacitated from normal play. This study concluded that inadequate fitness, high bowling workload and bowling technique all have a multi-factorial role in predisposing a bowler to increased risk for injury. These variables did not act alone, but have all contributed to recurring injuries. The bowling action alone would not have been detrimental if the workloads were not in excess of the recommended guidelines. Furthermore the workload would not have been as detrimental if the bowlers were well conditioned and uninjured. Management of minor injuries and adequate recovery time, coupled with adequate and relevant fitness preparation would better prepare fast bowlers for the demands of the game.

Thesis (MScPhysio)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Aim: The aim of the study was to improve understanding of the hip joint kinematics in cricket fast bowlers and to ascertain whether a relationship exists between hip joint biomechanical parameters, including kinematics, ROM characteristics and lumbar symptoms. Study design: A descriptive cross-sectional study was conducted. Participants: Sixteen adult male fast bowlers between the ages of 18 and 40 years old, playing first-club league, were featured in the study. Main outcome measures: To obtain data with regards to the training history, as well as the nature of lumbar-spine symptoms experienced by the cricket fast bowlers, a newly designed questionnaire was compiled. For analysis of the front foot hip joint ROM and kinematics, the biomechanical equipment used included: a two-dimensional Canon MV950 Digital Video Camcorder, a Kodak EasyShare C310 camera and XSENS Motion Tracking equipment (Xsens Technologies B. V., Enschede, Netherlands). Results: Eight of the sixteen bowlers in our study experienced LBP in the season with seven of these bowlers presenting with recent symptoms most of which are experienced after bowling a spell and described as “tightness” or a “stabbing pain” in the lower back. Intensity of LBP ranged between 1/10 to 8/10. Front foot hip joint kinematics of fast bowlers showed highly individualised patterns of movement between different subjects. Medium amplitude movements in the flexion/extension as well as the rotation plane of movement showed a significant difference in bowlers with- and without LBP. No significant differences between groups with LBP and without LBP were found in the three passive hip ROM measurements. Conclusions: It has proved to be very difficult to improve the understanding of the front foot hip biomechanics in cricket fast bowlers due to the high inter-subject variability. Variability in movement patterns remains under-researched by sports biomechanics. Although decreased hip mobility could alter mechanical forces transmitted to the lumbar spine and therefore predispose or be a causative factor in LBP development, this study found no significant relation between these parameters. The sample size was very small in this study which will influence the validity of results. Our study confirmed the high incidence of LBP and preventative efforts for bowlers should therefore be strongly supported. / AFRIKAANSE OPSOMMING: Doelwit: Die doelwit van die studie was om die heupgewrig kinematika van krieket snelboulers beter te verstaan en om vas te stel of daar ‘n verwantskap bestaan tussen heupgewrig biomeganiese parameters, insluitende kinematika, omvang van beweging karakter en lumbale simptome. Studie ontwerp: ‘n Deursneë beskrywende studie is onderneem. Deelnemers: Sestien volwasse manlike snelboulers tussen die ouderdomme van 18 en 40 jaar oud wat eerste liga speel maak deel uit van die studie. Hoof uitkoms maatreëls: ‘n Nuut ontwerpte vraelys is opgestel om data aangaande oefen geskiedenis sowel as aard van lumbale simptome wat deur krieket snelboulers ervaar word in te samel. Die biomeganiese apparaat wat gebruik is vir die analiese van die voorvoet heup omvang van beweging, sowel as die kinematika, sluit in: ‘n twee dimensionele Canon MV950 Digitale Video Camcorder, ‘n Kodak EasyShare C310 kamera en XSENS beweging volgende apparaat (Xsens Technologies B. V., Enschede, Netherlands). Resultate: Agt van die sestien boulers in ons studie het lae rug pyn in die seisoen ervaar. Sewe van die boulers het gepresenteer met onlangse simptome waarvan die meeste na ‘n bouler se boulbeurt ervaar is en beskryf was as ‘n “styfheid” of “steekpyn” in die lae rug. Die intensiteit van die lae rug pyn het gewissel tussen 1/10 en 8/10. Voorvoet heup kinematika van snelboulers het hoogs individualistiese patrone van beweging getoon tussen verskillende deelnemers. Medium amplitude bewegings in die fleksie/ekstensie sowel as die rotasie plein van beweging het ‘n beduidende verskil tussen boulers met- en sonder lae rug pyn getoon. Geen beduidende verskille tussen die groep met- en sonder rugpyn is gevind met die drie passiewe heup omvang van beweging meetings nie. Gevolgtrekkings: Dit blyk baie moelik te wees om die voorvoet heup biomeganika in krieket snelboulers beter te verstaan a.g.v. die hoë inter-deelnemer veranderlikheid. Veranderlikheid in bewegings patrone is nog nie genoeg nagevors deur sport biomeganici nie. Alhoewel ingekorte heup mobiliteit meganiese kragte wat deur die lumbale werwelkolom gaan kan wysig, en sodoende die ontwikkeling van lae rug pyn kan predisponeer of ‘n oorsakende faktor kan wees, het hierdie studie nie ‘n beduidende verwantskap tussen die parameters gevind nie. Die steekproef groote was baie klein en dit sal die geldigheid van die resultate beïnvloed. Ons studie het die hoë insidensie van lae rug pyn bevestig en pogings tot voorkomende maatreëls moet daarom ten sterkste ondersteun word.