Browsing by Author "Rainsford, Ian George"
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- ItemThe role of the gluteus maximus during prone hip extension(Stellenbosch : Stellenbosch University, 2015-12) Rainsford, Ian George; Welman, Estelle; Venter, Rachel Elizabeth; Stellenbosch University. Faculty of Education. Dept. of Sport Science.ENGLISH ABSTRACT: Background: The clinical prone hip extension (PHE) test is used to assess lumbo-pelvic function with a large focus placed on the activation of the gluteus maximus (Gmax), and is also used as a prescribed exercise in the treatment of Gmax recruitment deficits. The activation sequences (AS) are compared to those of the ‘golden standard’ as set out by Janda (1991). Gmax activation becomes important due to its role in injury prevention as well as maintenance of lower limb alignment. Previous research into the AS reveals no consistent order, questioning the functionality of the PHE. Objective: The current study set out to determine whether a consistent AS exists during the PHE and, in the presence of an erroneous AS, whether one can achieve the proposed AS with concentrated gluteal training. The current study also looked into the AS of more functionally loaded movements. The study further looked at the influence of improved Gmax recruitment on lower limb alignment. Methods: Pre- (n=18) and post-testing (n=7) of the muscle AS (time-normalized onsets) (with electromyography) were assessed in healthy young club-level netball players during the PHE, quadruped opposite arm/leg extension (QALE), and the single limb squat (SQT) along with lower limb alignment (valgus and knee-over-toe angles). The following muscles were included in the assessment: Gluteus maximus, bicep femoris, and lumbar erector spinae. Onsets were reported relative to gluteus maximus. Following pre-testing the players then entered a nine-week gluteal training intervention. Results: No consistent AS was noted at pre-testing (n=18) with the Gmax onset occurring after that of the lumbar erector spinae in both non-dominant and dominant PHE. At post-testing (n=7) the Gmax onset occurred earlier (non-dominant first and dominant second) with the lumbar erector spinae shifting later (dominant significantly, p<0.05). During the QALE and SQT movements, Gmax onset was consistently not the first muscle to become active at pre- and post-testing. No change in lower limb alignment was observed with no change in gluteal muscle onset or amplitude (p>0.05) during the SQT. Conclusion: The gluteal training intervention seems to have improved gluteal recruitment during the PHE but this did not have an influence on lower limb alignment during the SQT bringing to question the usage of the PHE in the assessment of Gmax function. The AS (both non-dominant and dominant PHE) agree more closely with the suggested norm and hence lends weight that it can be used as a reference. The QALE and SQT don’t appear to be suitable replacements for the PHE.