Realización de los análisis apropiados

Based on the above, it is hypothesised that golfers would have more ER on the dominant shoulder and more IR on the lead shoulder while controls would have no difference in GHJ rotations patterns between sides. It is hypothesised that golfers would have a more upward rotated Scapula on the dominant shoulder compared to the lead side while this pattern would not be significant in controls. In addition, it is hypothesised that golfers would have a longer pectoralis muscle on the dominant side compared with the lead shoulder while the opposite would be found in controls.

METHOD

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ANALYSIS

Healthy shoulders were included in analysis and sorted according to dominant and non-dominant sides. The mean of three measures was calculated. Outliers were removed. Normality of

distributions was ensured with Shapiro Wilk and Kolmogorov-Smirnow tests. Descriptive analysis was run and Paired t-tests used for within-group analysis and independent t-tests used for between- group analysis (significance level is set at 0.05).

RESULTS

Data from 36 male controls (mean age 24.28years STD 6.81 years) were included in the study. Data from 45 professional male golfers on the Challenge Tour (mean age 27.91 years STD 4.74 years) were included in the study.

Within group analysis

164 Table 36. There is no significant differences in side to side comparison between controls in the GHJ total arc of rotation (dominant side133.73° STD 13.76° and non-dominant side 132.13° STD

13.49°), nor in IR (dominant side 52.25° STD 23.81° non dominant side 55.25° STD 12.04°), nor in ER (dominant side 81.18° STD 11.13° and non-dominant side 79.25° STD 10.91°). The dominant Scapula of controls is more upwardly-rotated in both neutral (dominant side 3.72° STD 4.18° and non-dominant side 2.38° STD 3.41°) and in 60° of shoulder abduction(dominant side 10.17° STD 6.36° and non-dominant side 8.53° STD 3.61°). Only the Scapular rotation angle in neutral

achieved significance between sides (paired t-test p=0.04). Controls exhibited a significantly longer Pectoralis Minor muscle on the non-dominant side (dominant side 16.30cm STD 1.30cm and non- dominant side 16.84cm STD 1.31cm. Paired T-test p=0.01), however the difference of 0.54cm is less than MDC95% reported for this measure in Chapter 3. (MDC95%=0.92cm-0.95cm).

Results from paired t-tests showed that there is no difference in side to side comparison between in golfers in the GHJ total arc of rotation (dominant side149.03° STD 11.55° and non-dominant side 154.11° STD 15.87°), nor in IR (dominant side 58.47° STD 11.72° non dominant side 63.19° STD 12.12°), nor in ER (dominant side 89.68° STD 11.65° and non-dominant side 90.29° STD 9.05°). The dominant Scapula of golfers is significantly more upwardly-rotated in neutral (dominant side 5.41° STD 3.22° and non-dominant side 3.17° STD 3.80°) (p=0.01) and in the non-dominant side is significantly more upwardly-rotated in 60° of shoulder abduction(dominant side 6.89° STD 3.77° and non-dominant side 8.89° STD 3.36°)(p=0.01). Golfers had a significantly longer Pectoralis Minor muscle on the dominant side (dominant side 16.89cm STD 1.14cm and non-dominant side 15.82cm STD 1.20cm. Paired T-test p=0.01). The difference of 0.87cm is less than MDC95% reported for this measure in Chapter 3. (MDC95%=0.92cm-0.95cm).

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Table 36. Descriptive for variables and results of t-tests in both golfers and controls.

Golfers Mean (STD) degrees Paired t-test golfers p value Controls mean (STD) degrees Paired t-test controls p value Mean difference degrees Independent t- test p value Dom TROM 149.03(11.55) 133.73(13.76) -15.30 0.01 Non- dom TROM 154.11(15.87) 132.13(13.49) -21.98 0.01 Dom IR 58.46(11.72) 52.25(23.81) -2.52 0.55 Non- dom IR 63.19(12.12) 55.25(12.04) -8.50 0.01 Dom ER 89.68(11.65) 81.18(11.13) -7.94 0.01 Non- dom ER 90.29(9.05) 79.25(10.91) -11.04 0.01 Dom SR 0° 5.43(3.18) 0.01 3.72(4.18) 0.04 -1.71 0.05 Non-dom SR 0° 3.03(3.72) 2.38(3.41) 0.65 0.40 Dom SR 60° 6.93(3.78) 0.01 10.17(6.36) 3.24 0.01 Non-dom SR 60° 8.67(3.52) 8.53(3.61) -0.14 0.86 Dom PM 16.67(1.13)cm 0.01 16.30(1.30)cm 0.01 -0.36cm 0.20 Non-dom PM 15.80(1.25)cm 16.84(1.31)cm 1.04cm 0.00

Abbreviations: Dom=dominant; Non-dom = non-dominant; TROM=total range of motion; IR=internal rotation; ER = external rotation; SR= Scapular rotation in coronal plane; PM=Pectoralis Minor length; °=degrees; cm =centimetres; STD = standard deviation.

Between-group analysis

Significant difference was found bilaterally in GHJ total arc of rotation (15.30° -21.98° greater total arc of rotation in golfers p=0.01) and bilaterally in GHJ ER (7.94° -11.04° greater GHJ IR rotation in golfers p=0.01) and in non-dominant GHG IR (8.50° greater GHJ IR rotation in golfers p=0.01) between golfers and controls. It is noted that for all these variables other than dominant shoulder IR golfers have significantly more measures of motion. There was no significant difference in Scapular rotation between golfers and controls in neutral but controls had significantly more upward rotation on the dominant side compared with the dominant side of golfers in 60° of abduction (difference = 3.24° p=0.01). No significant length difference was noted between golfers and controls in Pectoralis Minor length on the dominant side. Significance was achieved in Pectoralis Minor length on the non-dominant side with controls exhibiting a longer Pectoralis Minor length by 1.04 (p=0.01).

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DISCUSSION

GHJ rotation

It was hypothesised that golfers would have more ER on the dominant shoulder and more IR on the lead shoulder while controls would have no difference in GHJ rotations patterns between sides. The results do not support his hypothesis as professional golfers were not found to have a unique pattern of increased GHJ rotations on either side. However, golfers’ shoulders did have significantly more degrees of rotation than controls in total arc of rotation and external rotation. Golfers have more internal rotation than controls, this was significant in the lead/non-dominant shoulder but not on the dominant side. Results are in keeping with those of previous studies (Brumitt et al., 2008; Sell et al., 2007) in players with a lower handicap than golfers included in this study (Table 1.). Methods used to determine the end of rotation range differs between studies so care needs to be taken when comparing the definite measurements. The present study used the movement of the Coracoid as an indication of end of range whereas previous studies used over pressure and capsular end feel to determine limits range as a result definite measurements would be expected to be less in the current study. Based on this probability it can be conclude that the professional elite golfers than the present study exhibited greater range of shoulder rotations than those reported in the previous studies, but this comparison is conjecture. The aim of the current study is to provide a reference for ranges of shoulder rotation in healthy elite professional golfers for screening purposes it does not examine the influence of stretching in these ranges, therefore, cautiousness needs to be taken when interpreting the clinical implications of the results. Previous research advocating the benefits of aggressive stretching of the shoulder for golfers was done on golfers with a mean age of 58 years who are known to loose range due to increased age. In addition, rotation and increase of range of the X- factor during the back swing does not only occur at the shoulder and although awareness of the

167 golfer’s anatomical shoulder make up is useful it is only one component of the kinetic link in the summation of forces between the hip, and trunk, and upper limbs.

Scientific evidence of what physical characteristics improve performance in sports will give clinicians parameters for training programs and prevention of injury. Golfers’ shoulders have significantly more degrees of rotation than controls in total arch of rotation and external rotation. The professional golfers in this study were not found to have a unique pattern of shoulder rotations between sides. Thus supporting that side to side comparison of shoulder rotational range is

appropriate in the golfer when screening. If unique loss of range is noted between sides in the context of a loss of total rotational range it may have consequences for the efficacy of the swing technique as well imply risk to injury

Table 37. Passive GHJ ROM in golfers reported in the literature.

Author GHJ ER