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Hip and shoulder internal rotation range of motion deficits in professional tennis players
Hip and shoulder internal rotation range of motion deficits in professional tennis players V B Vad 1'2'3'4, A Gebeh 5, D Dinesl,2,D Altchek & B Norris 3 1The Hospital for special surgery, New York, New York, USA. 2The Weill Medical College of Cornell University, Ne.w York, New York, USA. 3Associationof_Tennisprofessionals Circuit, Ponte Verda Beach, Florida, USA. 4Professional Golfers' AssociationTour. ~Department of Rehabilitation Medicine, Mount Sinai Hospital, New York, New York, USA.
Vad, V, B, Gebeh, A, Dines, D, Altchek, D, & Norris, B (2003). Hip and shoulder internal rotation range of motion deficits in professional tennis players. Journal of Science and Medicine in Sport 6 (1): 71-75. One hundred tennis players were recruited from the professional men's tennis tour to investigate the correlation between hip internal rotation deficits and low back pain (LBP), as well as shoulder internal rotation deficits and shoulder pain. A statistically significant correlation was observed between dominant shoulder internal rotation deficits and shoulder pain. Also observed was a statistically significant correlation between lead hip internal rotation deficits and lumbar extension deficits with LBP. We conclude that due to repetitive demands on the dominant shoulder and repetitive pivoting at the lead hip, the cycle of microtrauma and scar formation leads to capsular contracture and subsequent reduction in internal range of motion. It is likely that the limitation in lumbar extension in the symptomatic group is not only due to decreased flexibility from an increased load on the spine, but also due to a protective mechanism to prevent further exacerbation of the LBP. Physical conditioning that includes shoulder as well as hip internal rotation stretching programs should therefore be essential aspects in the treatment of tennis players with shoulder pain and LBP respectively.
Introduction L a c k of flexibility in a t h l e t e s h a s b e e n r e l a t e d to b o t h a d e c r e a s e in p e r f o r m a n c e a n d a n i n c r e a s e in m u s c u l a r i n j u r i e s (1). R e p e a t e d d e m a n d s o n a m u s c l e m a y c a u s e it to s h o r t e n b e c a u s e of t h e v i c i o u s cycle of m i c r o t r a u m a , s c a r f o r m a t i o n , followed b y m o r e m i c r o t r a u m a w i t h c o n t i n u e d u s e . T h e h i s t o l o g i c b a s i s of t h e cycle of m i c r o t r a u m a d a m a g e to t h e m u s c l e h a s b e d n well described(2). S i n c e t e n n i s r e q u i r e s r e p e a t e d m u s c l e c o n t r a c t i o n s , t i g h t n e s s in t e n n i s p l a y e r s c a n b e a s i g n i f i c a n t s o u r c e of p o t e n t i a l i n j u r y , p a i n a n d s u b s e q u e n t d e c r e a s e d p e r f o r m a n c e . T h i s is b e c a u s e t h e r e d u c e d j o i n t r a n g e of m o t i o n r e s u l t s in m u s c u l o s k e l e t a l a d a p t a t i o n s t h a t d e c r e a s e t h e efficiency of force p r o d u c t i o n t h e r e b y i n c r e a s i n g t h e l i k e l i h o o d of i n j u r y to t h e m u s c l e . A l t h o u g h t h e r e l a t i o n s h i p b e t w e e n s h o u l d e r i n t e r n a l r o t a t i o n deficits i n professional tennis players has previously been investigated, the relationship b e t w e e n h i p i n t e r n a l r o t a t i o n deficits a n d low b a c k p a i n in t e n n i s p l a y e r s h a s not, to o u r k n o w l e d g e , b e e n p r e v i o u s l y i n v e s t i g a t e d , T h e p r e s e n c e of deficits in a m a j o r i t y of s h o u l d e r s w i t h m i c r o i n j u r i e s is well e s t a b l i s h e d (a,4). A d a p t a t i o n s in g l e n o h u m e r a l r o t a t i o n h a v e b e e n d e m o n s t r a t e d in t e n n i s a t h l e t e s w h o 71
Hip and shoulder internal rotaion range...
developed d e c r e a s e d internal rotation of the d o m i n a n t s h o u l d e r w h e n c o m p a r e d with their n o n - d o m i n a n t side (5,6), or with players from other sports(7). The relationship between hip mobility a n d LBP in non-athletes h a s b e e n examined in a few reports. Mellin(8) examined hip mobility in 476 patients with r e c u r r e n t LBP and showed t h a t patients who h a d more hip external rotation t h a n hip internal rotation were more likely to develop LBP. In a n o t h e r s t u d y examining patients with unspecified LBP, patients who h a d m o r e hip external rotation t h a n hip internal rotation were more likely to have LBP (9). The p r i m a r y aim of this s t u d y w a s to determine if there w a s a n y correlation between hip internal rotation deficits a n d LBP, as well as shoulder internal rotation deficits and shoulder pain in professional tennis players. The secondary aim of the s t u d y was to determine if l u m b a r range of motion deficits correlated with LBP in these athletes.
Methods The subjects in this s t u d y were professional m e n tennis players from the Association of Tennis Professionals Circuit. One h u n d r e d players, all men, were evaluated and the m e a n age w a s 25.4 years (range 17-37 years). S t a n d a r d goniometric range of motion m e a s u r e m e n t s were done on the d o m i n a n t a n d n o n - d o m i n a n t u p p e r extremities and on the lead a n d non-lead hips for the lower extremities. Shoulder flexibility was m e a s u r e d with the subjects supine and the s c a p u l a stabilised. The shoulder was a b d u c t e d to 90°and the glenohumeral joint rotated into m a x i m u m internal rotation. Crosschest adduction was m e a s u r e d as the distance in centimetres (cm) from the tip of the contralateral acromion to the elbow of the ipsilateral a d d u c t e d a r m with the subject in the supine position. For the lower extremities, with the subjects supine, lead a n d non-lead m e a s u r e m e n t s were t a k e n with the hip flexed, a b d u c t e d and externally rotated (Fabere maneuvre). The vertical knee-to-floor distance during the Fabere m a n e u v r e we referred to as the FABERE's distance. Finger-to-floor and b a c k extension m e a s u r e m e n t s were also recorded. All subjects were a s k e d if they h a d LBP limiting tennis p e r f o r m a n c e for greater t h a n 2 weeks. Subjects were then divided into s y m p t o m a t i c a n d a s y m p t o m a t i c groups b a s e d on this information. Similarly, there were two groups for the shoulder. M e a s u r e m e n t s of s y m p t o m a t i c vs. a s y m p t o m a t i c individuals were c o m p a r e d a n d the d a t a were analysed using the Wilcox SignedR a n k Test with statistical significance set at p<0.05.
Results Of the 100 participants, 40 were s y m p t o m a t i c for LBP limiting p e r f o r m a n c e for greater t h a n 2 weeks and 44 participants were s y m p t o m a t i c for s h o u l d e r p a i n limiting p e r f o r m a n c e for greater t h a n 2 weeks. This results in a 40% prevalence of LBP and, a 44% prevalence of shoulder p a i n in o u r s t u d y group. Table 1 displays the results for the finger-to-floor distance, l u m b a r extension, 90 ° a b d u c t i o n / i n t e r n a l rotation of shoulder, FABERE's distance, c r o s s - c h e s t distance, and 90 ° flexion/internal rotation of hip for b o t h the s y m p t o m a t i c a n d a s y m p t o m a t i c groups. Table 2 shows the differences between the lead a n d non-lead sides for the s y m p t o m a t i c a n d the a s y m p t o m a t i c groups for 90 ° a b d u c t i o n / i n t e r n a l rotation of shoulder, FABERE's distance, c r o s s - c h e s t distance and 90 ° flexion/internal rotation of the hip. From Table 2, it c a n be observed t h a t in the s y m p t o m a t i c low b a c k group, there w a s a 7.6 ° deficit in
72
Hip and shoulder internal rotaion range... /
Symptomatic LBP and Shoulder Pain Respectively Finger-to-floor distance(cm) Lumbar extension (degrees)*
90 ° abd/IR* FABERE's (cm)*
Cross-chest (cm)* 90 ° flex/IR*
Asymptomatic LBP and Shoulder Pain Respectively
12.2_+2.4 11.4
10.3_+2.8 20.3
(p=0.12)
lead hip
non-lead hip
lead hip
non-lead hip
16,1_+1.3 14.6_+1.4
31.6_+1.6 6.4_+1.2
24.2_+1.2 9.1_+1.2
31.7_+1.4 5.9_+1.3
lead shoulder
non-lead shoulder
lead shoulder
non-lead ShOUlder
11,6_+1.2 12.2_+1.1
4.4_+1.3 19.8_+1.6
6.5_+1.2 18.1_+1,3
4.2_+1,2 21,5_+1,8
Note: Data presented as mean.+SD * P<0.05, significant.
Tabel 1:
Rangeof motion data for players in the ATP Circuit iN= 100).
Symptomatic LBP arid Shoulder Pain Respectively 90 ° abd/IR* FABERE's (cm)* Cross-chest (cm)* 90 ° flex/IR*
15.2 8.6 7.2 7.6
Asymptomatic LBP and Shoulder Pain Respectively 7.5 3.2 2.3 3.2
Note: Data presented as mea .+SD * P<0.05, significant,
Table 2:
Differences of range of motion between lead and non lead sides for players in the ATP Circui (N=100).
hip internal rotation in the lead hip when compared to the non-lead hip, whereas there was only a 3.2 ° difference for the asymptomatic group (p<0.05). Also, in the symptomatic low back group, the difference in FABERE's distance was 8.6 cm w h e n comparing the lead and non-lead hip while that for the asymptomatic group was 3.2 cm (p<0.05}. As seen in Table 1, l u m b a r extension in the symptomatic low b a c k group had a range of 11.4 ° versus 20.3 ° for the a s y m p t o m a t i c group (p<0.05). The difference in finger-to-floor distance between the symptomatic and asymptomatic group was not statistically significant (p=0.12). In the symptomatic shoulder group, there was a 15.2 ° deficit in the lead shoulder w h e n compared to the non-lead shoulder at 90 ° abduction in internal rotation while that for the asymptomatic group was 7.5 ° (p<0.05}. For crosschest adduction, the difference between the lead and the non-lead shoulder in the symptomatic group was 7.2 cm b u t only 2.3 cm in the asymptomatic group
(p<0.05).
DisCussion Adaptations in glenohumeral rotation have been demonstrated not only in tennis athletes b u t also in baseball players. These range of motion adaptations result in a decrease in internal rotation of the shoulder as shown in our study. Chandler et al. (5) did flexibility m e a s u r e m e n t s in junior elite tennis players and
73
Hip and shoulder internal rotaion range...
theorised t h a t the decrease in s h o u l d e r internal rotation t h a t they observed, particularly on the d o m i n a n t side, w a s due to an a d a p t a t i o n of the posterior shoulder m u s c u l a t u r e a n d c a p s u l a r s t r u c t u r e s to the tennis stroke. H a r r y m a n et al.(101 d e m o n s t r a t e d t h a t in cadaveric shoulders in which the posterior capsules were experimentally tightened, glenohumeral rotation w a s subsequently decreased. We theorise t h a t a decrease in internal rotation of the shoulder results in a decrease in the efficiency of force production thereby increasing the chance of injury to the shoulder m u s c u l a t u r e . This altered a n d less efficient form not only contributes to shoulder pain b u t could also be a factor in elbow injuries in tennis players. In this study, we also observed excessive internal rotation deficits in the lead hip w h e n c o m p a r e d to the non-lead hip and t h a t lead hip internal rotation deficits correlated highly to the p r e s e n c e of LBP. The lead hip in tennis players could be experiencing repetitive forces during play resulting in c a p s u l a r e o n t r a c t u r e s and a s u b s e q u e n t decrease in internal rotation. Previous studies done on a professional golfer showed t h a t increasing the range of hip t u r n led to a cessation of LBP (n). We therefore theorise t h a t a reduction in hip mobility increases forces t r a n s m i t t e d to the l u m b a r spine. I m p r o v e m e n t in the range of hip t u r n therefore translates to decreased loads placed on the spine. We also observed a statistically significant difference in l u m b a r extension between the s y m p t o m a t i c and a s y m p t o m a t i e groups. It is likely t h a t the limitation in l u m b a r extension in the s y m p t o m a t i c group is not only due to decreased flexibility from an increased load on the spine, b u t also due to a protective m e c h a n i s m to prevent further exacerbation of the LBP.
ConClusion In our s t u d y sample, excessive internal rotation deficits in the d o m i n a n t lead shoulder as well as in the lead hip highly correlated to the p r e s e n c e of s h o u l d e r pain and LBP respectively. We theorise t h a t due to repetitive d e m a n d s on the d o m i n a n t shoulder a n d repetitive pivoting at the lead hip, the cycle of m i c r o t r a u m a and scar formation leads to c a p s u l a r c o n t r a c t u r e a n d subsequent reduction in internal range of motion. This decrease in internal rotation m a y decrease efficiency of force production, thereby increasing the chance of injury, p e r p e t u a t i n g a n d worsening the cycle. We also observed t h a t l u m b a r extension deficits highly correlated to LBP. Physical conditioning t h a t includes shoulder as well as hip internal rotation stretching p r o g r a m s should -therefore be essential aspects in the t r e a t m e n t of tennis players with s h o u l d e r p a i n and LBP respectively.
References (1) Shellock, F.G., Prentice, W.E. (1985). Warming-up and stretching for improved physical performance and prevention of sports-related injuries. Sports Medicine 2 (4): 267-278. (2) Garrett, W.E. (1986).t The Lower Extremity and Spine in Sports Medicine. CV Mosby. St. Louis, 42-58. (3) Abrams, J. S. (1991). Special shoulder problems in the throwing athlete: Pathology, diagnosis, and non operative management. Clinics in Sports Medicine 10 {4): 839-861. (4) Silliman, J. F., Hawkins, R. J. (1991). Current concepts and recent advances in the athlete's shoulder. Clinics in Sports Medicine 10 (4): 693-705. (5) Chandler, T.J., Kibler, W.B., Uhl, T.L, et al. (1990). Flexibility comparisons of junior elite tennis players to other athletes. American Journal of Sports Medicine 18 (2): 134-136. (6) Ellenbecker, T.S. (1995). Rehabilitation of shoulder and elbow injuries in tennis players.
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Hip and shoulder internal rotaion range... Clinics in Sports Medicine 14 (1): 87-110. (7) Kibler, W.B., Chandler, T.J. (1993). Musculoskeletal adaptations and injuries associated with intense participation in youth sports, in Cahill B {Ed): The Effect of Intensive Training on Prepubescent Athletes in Sports. AAOS, Chicago. 203-216. (8) Mellin, G. (1988). Correlation of hip mobility with degree of back pain and lumbar spinal mobility in chronic low back pain patients. Spine 13 (16): 668-670. (9) Ellison J. B., Rose, S. J., Sahrmann, S. A, (1990). Patterns of hip rotation range of motion: A comparison between healthy subjects and patients with low back pain. Physical Therapy 70 (9): 537-41. (10) Harryman, D. T. II, Sidles, J. A., Clark, J. M. et al. (1990). Translation of the humeral head on the glenoid with passive glenohumeral motion. Journal o f Bone and Joint Surgery (Am) 72 (9): 1334-1343. (11) Gimshaw, P. N., and Burden, A. M. (2000). Case report: reduction of low back pain in a professional golfer. Medicine and Science in Sports and Exercise 32 (10): 1667-1673.
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Vad, V, B, Gebeh, A, Dines, D, Altchek, D, & Norris, B (2003). Hip and shoulder internal rotation range of motion deficits in professional tennis players. Journal of Science and Medicine in Sport 6 (1): 71-75. One hundred tennis players were recruited from the professional men's tennis tour to investigate the correlation between hip internal rotation deficits and low back pain (LBP), as well as shoulder internal rotation deficits and shoulder pain. A statistically significant correlation was observed between dominant shoulder internal rotation deficits and shoulder pain. Also observed was a statistically significant correlation between lead hip internal rotation deficits and lumbar extension deficits with LBP. We conclude that due to repetitive demands on the dominant shoulder and repetitive pivoting at the lead hip, the cycle of microtrauma and scar formation leads to capsular contracture and subsequent reduction in internal range of motion. It is likely that the limitation in lumbar extension in the symptomatic group is not only due to decreased flexibility from an increased load on the spine, but also due to a protective mechanism to prevent further exacerbation of the LBP. Physical conditioning that includes shoulder as well as hip internal rotation stretching programs should therefore be essential aspects in the treatment of tennis players with shoulder pain and LBP respectively.
Introduction L a c k of flexibility in a t h l e t e s h a s b e e n r e l a t e d to b o t h a d e c r e a s e in p e r f o r m a n c e a n d a n i n c r e a s e in m u s c u l a r i n j u r i e s (1). R e p e a t e d d e m a n d s o n a m u s c l e m a y c a u s e it to s h o r t e n b e c a u s e of t h e v i c i o u s cycle of m i c r o t r a u m a , s c a r f o r m a t i o n , followed b y m o r e m i c r o t r a u m a w i t h c o n t i n u e d u s e . T h e h i s t o l o g i c b a s i s of t h e cycle of m i c r o t r a u m a d a m a g e to t h e m u s c l e h a s b e d n well described(2). S i n c e t e n n i s r e q u i r e s r e p e a t e d m u s c l e c o n t r a c t i o n s , t i g h t n e s s in t e n n i s p l a y e r s c a n b e a s i g n i f i c a n t s o u r c e of p o t e n t i a l i n j u r y , p a i n a n d s u b s e q u e n t d e c r e a s e d p e r f o r m a n c e . T h i s is b e c a u s e t h e r e d u c e d j o i n t r a n g e of m o t i o n r e s u l t s in m u s c u l o s k e l e t a l a d a p t a t i o n s t h a t d e c r e a s e t h e efficiency of force p r o d u c t i o n t h e r e b y i n c r e a s i n g t h e l i k e l i h o o d of i n j u r y to t h e m u s c l e . A l t h o u g h t h e r e l a t i o n s h i p b e t w e e n s h o u l d e r i n t e r n a l r o t a t i o n deficits i n professional tennis players has previously been investigated, the relationship b e t w e e n h i p i n t e r n a l r o t a t i o n deficits a n d low b a c k p a i n in t e n n i s p l a y e r s h a s not, to o u r k n o w l e d g e , b e e n p r e v i o u s l y i n v e s t i g a t e d , T h e p r e s e n c e of deficits in a m a j o r i t y of s h o u l d e r s w i t h m i c r o i n j u r i e s is well e s t a b l i s h e d (a,4). A d a p t a t i o n s in g l e n o h u m e r a l r o t a t i o n h a v e b e e n d e m o n s t r a t e d in t e n n i s a t h l e t e s w h o 71
Hip and shoulder internal rotaion range...
developed d e c r e a s e d internal rotation of the d o m i n a n t s h o u l d e r w h e n c o m p a r e d with their n o n - d o m i n a n t side (5,6), or with players from other sports(7). The relationship between hip mobility a n d LBP in non-athletes h a s b e e n examined in a few reports. Mellin(8) examined hip mobility in 476 patients with r e c u r r e n t LBP and showed t h a t patients who h a d more hip external rotation t h a n hip internal rotation were more likely to develop LBP. In a n o t h e r s t u d y examining patients with unspecified LBP, patients who h a d m o r e hip external rotation t h a n hip internal rotation were more likely to have LBP (9). The p r i m a r y aim of this s t u d y w a s to determine if there w a s a n y correlation between hip internal rotation deficits a n d LBP, as well as shoulder internal rotation deficits and shoulder pain in professional tennis players. The secondary aim of the s t u d y was to determine if l u m b a r range of motion deficits correlated with LBP in these athletes.
Methods The subjects in this s t u d y were professional m e n tennis players from the Association of Tennis Professionals Circuit. One h u n d r e d players, all men, were evaluated and the m e a n age w a s 25.4 years (range 17-37 years). S t a n d a r d goniometric range of motion m e a s u r e m e n t s were done on the d o m i n a n t a n d n o n - d o m i n a n t u p p e r extremities and on the lead a n d non-lead hips for the lower extremities. Shoulder flexibility was m e a s u r e d with the subjects supine and the s c a p u l a stabilised. The shoulder was a b d u c t e d to 90°and the glenohumeral joint rotated into m a x i m u m internal rotation. Crosschest adduction was m e a s u r e d as the distance in centimetres (cm) from the tip of the contralateral acromion to the elbow of the ipsilateral a d d u c t e d a r m with the subject in the supine position. For the lower extremities, with the subjects supine, lead a n d non-lead m e a s u r e m e n t s were t a k e n with the hip flexed, a b d u c t e d and externally rotated (Fabere maneuvre). The vertical knee-to-floor distance during the Fabere m a n e u v r e we referred to as the FABERE's distance. Finger-to-floor and b a c k extension m e a s u r e m e n t s were also recorded. All subjects were a s k e d if they h a d LBP limiting tennis p e r f o r m a n c e for greater t h a n 2 weeks. Subjects were then divided into s y m p t o m a t i c a n d a s y m p t o m a t i c groups b a s e d on this information. Similarly, there were two groups for the shoulder. M e a s u r e m e n t s of s y m p t o m a t i c vs. a s y m p t o m a t i c individuals were c o m p a r e d a n d the d a t a were analysed using the Wilcox SignedR a n k Test with statistical significance set at p<0.05.
Results Of the 100 participants, 40 were s y m p t o m a t i c for LBP limiting p e r f o r m a n c e for greater t h a n 2 weeks and 44 participants were s y m p t o m a t i c for s h o u l d e r p a i n limiting p e r f o r m a n c e for greater t h a n 2 weeks. This results in a 40% prevalence of LBP and, a 44% prevalence of shoulder p a i n in o u r s t u d y group. Table 1 displays the results for the finger-to-floor distance, l u m b a r extension, 90 ° a b d u c t i o n / i n t e r n a l rotation of shoulder, FABERE's distance, c r o s s - c h e s t distance, and 90 ° flexion/internal rotation of hip for b o t h the s y m p t o m a t i c a n d a s y m p t o m a t i c groups. Table 2 shows the differences between the lead a n d non-lead sides for the s y m p t o m a t i c a n d the a s y m p t o m a t i c groups for 90 ° a b d u c t i o n / i n t e r n a l rotation of shoulder, FABERE's distance, c r o s s - c h e s t distance and 90 ° flexion/internal rotation of the hip. From Table 2, it c a n be observed t h a t in the s y m p t o m a t i c low b a c k group, there w a s a 7.6 ° deficit in
72
Hip and shoulder internal rotaion range... /
Symptomatic LBP and Shoulder Pain Respectively Finger-to-floor distance(cm) Lumbar extension (degrees)*
90 ° abd/IR* FABERE's (cm)*
Cross-chest (cm)* 90 ° flex/IR*
Asymptomatic LBP and Shoulder Pain Respectively
12.2_+2.4 11.4
10.3_+2.8 20.3
(p=0.12)
lead hip
non-lead hip
lead hip
non-lead hip
16,1_+1.3 14.6_+1.4
31.6_+1.6 6.4_+1.2
24.2_+1.2 9.1_+1.2
31.7_+1.4 5.9_+1.3
lead shoulder
non-lead shoulder
lead shoulder
non-lead ShOUlder
11,6_+1.2 12.2_+1.1
4.4_+1.3 19.8_+1.6
6.5_+1.2 18.1_+1,3
4.2_+1,2 21,5_+1,8
Note: Data presented as mean.+SD * P<0.05, significant.
Tabel 1:
Rangeof motion data for players in the ATP Circuit iN= 100).
Symptomatic LBP arid Shoulder Pain Respectively 90 ° abd/IR* FABERE's (cm)* Cross-chest (cm)* 90 ° flex/IR*
15.2 8.6 7.2 7.6
Asymptomatic LBP and Shoulder Pain Respectively 7.5 3.2 2.3 3.2
Note: Data presented as mea .+SD * P<0.05, significant,
Table 2:
Differences of range of motion between lead and non lead sides for players in the ATP Circui (N=100).
hip internal rotation in the lead hip when compared to the non-lead hip, whereas there was only a 3.2 ° difference for the asymptomatic group (p<0.05). Also, in the symptomatic low back group, the difference in FABERE's distance was 8.6 cm w h e n comparing the lead and non-lead hip while that for the asymptomatic group was 3.2 cm (p<0.05}. As seen in Table 1, l u m b a r extension in the symptomatic low b a c k group had a range of 11.4 ° versus 20.3 ° for the a s y m p t o m a t i c group (p<0.05). The difference in finger-to-floor distance between the symptomatic and asymptomatic group was not statistically significant (p=0.12). In the symptomatic shoulder group, there was a 15.2 ° deficit in the lead shoulder w h e n compared to the non-lead shoulder at 90 ° abduction in internal rotation while that for the asymptomatic group was 7.5 ° (p<0.05}. For crosschest adduction, the difference between the lead and the non-lead shoulder in the symptomatic group was 7.2 cm b u t only 2.3 cm in the asymptomatic group
(p<0.05).
DisCussion Adaptations in glenohumeral rotation have been demonstrated not only in tennis athletes b u t also in baseball players. These range of motion adaptations result in a decrease in internal rotation of the shoulder as shown in our study. Chandler et al. (5) did flexibility m e a s u r e m e n t s in junior elite tennis players and
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Hip and shoulder internal rotaion range...
theorised t h a t the decrease in s h o u l d e r internal rotation t h a t they observed, particularly on the d o m i n a n t side, w a s due to an a d a p t a t i o n of the posterior shoulder m u s c u l a t u r e a n d c a p s u l a r s t r u c t u r e s to the tennis stroke. H a r r y m a n et al.(101 d e m o n s t r a t e d t h a t in cadaveric shoulders in which the posterior capsules were experimentally tightened, glenohumeral rotation w a s subsequently decreased. We theorise t h a t a decrease in internal rotation of the shoulder results in a decrease in the efficiency of force production thereby increasing the chance of injury to the shoulder m u s c u l a t u r e . This altered a n d less efficient form not only contributes to shoulder pain b u t could also be a factor in elbow injuries in tennis players. In this study, we also observed excessive internal rotation deficits in the lead hip w h e n c o m p a r e d to the non-lead hip and t h a t lead hip internal rotation deficits correlated highly to the p r e s e n c e of LBP. The lead hip in tennis players could be experiencing repetitive forces during play resulting in c a p s u l a r e o n t r a c t u r e s and a s u b s e q u e n t decrease in internal rotation. Previous studies done on a professional golfer showed t h a t increasing the range of hip t u r n led to a cessation of LBP (n). We therefore theorise t h a t a reduction in hip mobility increases forces t r a n s m i t t e d to the l u m b a r spine. I m p r o v e m e n t in the range of hip t u r n therefore translates to decreased loads placed on the spine. We also observed a statistically significant difference in l u m b a r extension between the s y m p t o m a t i c and a s y m p t o m a t i e groups. It is likely t h a t the limitation in l u m b a r extension in the s y m p t o m a t i c group is not only due to decreased flexibility from an increased load on the spine, b u t also due to a protective m e c h a n i s m to prevent further exacerbation of the LBP.
ConClusion In our s t u d y sample, excessive internal rotation deficits in the d o m i n a n t lead shoulder as well as in the lead hip highly correlated to the p r e s e n c e of s h o u l d e r pain and LBP respectively. We theorise t h a t due to repetitive d e m a n d s on the d o m i n a n t shoulder a n d repetitive pivoting at the lead hip, the cycle of m i c r o t r a u m a and scar formation leads to c a p s u l a r c o n t r a c t u r e a n d subsequent reduction in internal range of motion. This decrease in internal rotation m a y decrease efficiency of force production, thereby increasing the chance of injury, p e r p e t u a t i n g a n d worsening the cycle. We also observed t h a t l u m b a r extension deficits highly correlated to LBP. Physical conditioning t h a t includes shoulder as well as hip internal rotation stretching p r o g r a m s should -therefore be essential aspects in the t r e a t m e n t of tennis players with s h o u l d e r p a i n and LBP respectively.
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