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Mobility Impairment in Type 2 DiabetesAssociation with muscle power and effect of Tai Chi intervention

RHONDA ORR, MEXSPSC1

TRACEY TSANG, BAPPSC(EXSPSC)(HONS)1

PAUL LAM, MBBS2

ELIZABETH COMINO, PHD3

MARIA FIATARONE SINGH, MD1,4

The increasing prevalence of type 2diabetes is a major health concern.Reducing the vascular complica-

tions of diabetes has been a primary focuso f t r e a t m e n t . H o w e v e r , t h e l e s s -recognized complications of physical dis-ability, cognitive impairment, anddepression that impact on quality of life(QOL) are also important primary careconsiderations in older patients with dia-

betes.Diabetes has been associated with agreater risk of decline in function and in-creased prospect of severe disability (1,2).Studies have sought to identify relation-ships or causal pathways between thesyn-dromes of mobility, disability, andneuropsychological function in adultswith type 2 diabetes (1,3). Few have si-multaneously examined these factors po-tentially modifiable by physical activity(4) across multiple domains or at morethan one point in time.

The dose of aerobic and resistance ex-

ercise necessary to achieve metabolic ben-efits in clinical trials has sometimes led topoor compliance (5). Older adults withdiabetes, often characterized by long-term sedentariness, overweight/obesity,and multiple comorbidities, may demon-strate better adherence to a low-intensity,low-impact exercise, such as Tai Chi. Al-though Tai Chi has demonstrated im-proved balance, gait speed, musclestrength, cardiorespiratory fitness, and

QOL in older adults (613), it has neverbeen tested specifically in a diabetic cohortfor benefits across multiple domains.

If Tai Chi was shown to be effectivefor mobility and other health outcomesrelevant to this cohort, it may present aviable alternative exercise modality. Theaim of this study was to examine the phys-iologic impairments associated with mo-bility in older adults with type 2 diabetes

and to investigate whether Tai Chi wouldimprove mobility in this cohort relative tosham exercise.

RESEARCH DESIGN AND

METHODS We conducted a 16-week single-blind, randomized, sham-exercise controlled trial with an intention-to-treat design. Baseline outcomesassessment was blinded. The study wasapproved by human research ethics com-mittees of the Universities of Sydney andNew South Wales. Written informed con-sent was obtained by participants.

We studied 38 type 2 diabetic pa-tients (79% female). We excluded pa-tients who were physically active,institutionalized, or cognitively impaired(Mini-Mental State Examination 24)(14) or had arthritic pain, unstable condi-tions, or disease precluding them fromthe planned exercises. Participants wererandomly allocated to the Tai Chi or con-trol groups, named Eastern or Westernexercise, both presented as being poten-

tially beneficial. The same exercise phys-iologist conducted both group exercise

sessions (10 min warm-up and cool-down, 45 min exercise) twice weekly. TheTai Chi group performed Tai Chi for Dia-betes (15), a 12-movement hybrid fromSun and Yang styles. Control subjects per-formed sham exercise (e.g., seated calis-thenics, stretching) (16).

All testing was conducted by the ex-ercise physiologist before randomizationand after completing 32 sessions (within5 months of randomization). Mobility im-pairment was determined from measuresof balance and gait speed (habitual and

maximal). Static balance (timed single-legstance with eyes open and closed), dy-namic balance (3-m forward tandemwalk), and balance index (summary scoreof static balance and postural control per-formance on a Chattecx balance platform)(17) were measured.

Physiological capacity assessmentsincluded knee extensor strength (one rep-etition maximum), peak power, peakcontraction velocity, and endurance (18)and overall exercise capacity (6-minwalk) (19). Health status included num-ber of comorbidities, body composition

(waist circumference, total body fat[%BF]) (20), fasting blood glucose, cog-nition (14), QOL (21), and attitude to-ward diabetes (22).

Statistical analyses were performedusing Statview 5.0. Values are reported asmeans SD or median (range). Groupswere compared using t tests or2. The effectof time and group-by-time interactionswere analyzed with repeated-measures

ANOVA. Variables, different betweengroups and their baseline values, were usedas covariatesin ANCOVAmodels. Relation-

ships between variables of interest were an-alyzed with multiple and forward stepwiselinear regression or Spearman rank-ordercorrelation. Statistical significance was ac-cepted at P 0.05.

RESULTS Participant characteris-tics and performance data are presentedin Table 1. Participants were obese (63%),displayed metabolic syndrome (82%),had one or more diabetes complications(40%), had comorbidities (predomi-nantly osteoarthritis [84%] and hyperten-

From the

1

Exercise and Sport Science Department, University of Sydney, Sydney, Australia; the

2

FamilyMedicine Department, University of New South Wales, New South Wales, Australia; the 3Health EquityTraining Research and Evaluation Department,University of New South Wales, New SouthWales, Australia;and the 4University of Sydney, Sydney, Australia, and Hebrew SeniorLife and Jean Mayer USDA HumanNutrition Center on Aging, Tufts University, Boston, Massachusetts.

Address correspondence and reprint requests to Rhonda Orr, P.O. Box 170, Lidcombe, NSW, 1825,Australia. E-mail: r.orr@fhs.usyd.edu.au.

Received for publication 1 June 2006 and accepted in revised form 7 June 2006.P.L.was the creator ofthe Tai Chi for Diabetesformand producer ofits video and isthe founder ofTai Chi

Productions, which distributes these videos and similar products and services.Abbreviations: %BF, total body fat; QOL, quality of life.

A table elsewhere in this issue shows conventional and Systeme International (SI) units and conversionfactors for many substances.

DOI: 10.2337/dc06-1130 2006 by the American Diabetes Association.The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby

marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

E m e r g i n g T r e a t m e n t s a n d T e c h n o l o g i e sB R I E F R E P O R T

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sion [76%]), and were recurrent fallers(16%; two or more falls in the past year).

At baseline, older age, more comorbidi-ties, higher %BF, poorer cognition, QOL,exercise capacity and muscle power, andslower gait speed and muscle contractionvelocity were related to poor balance (P0.043 to 0.0001). Similarly, older age,

poorer QOL, exercise capacity, balanceand muscle power, and slower musclecontraction velocity were related tos l o w e r g a i t s p e e d ( P 0 . 0 4 3 t o0.0001). Forward stepwise regressionmodels revealed that slower muscle con-traction velocity was the sole common in-dependent contributor to both balanceand gait impairment at baseline.

Balance (P 0.03) and maximal gaitspeed (P 0.005) improved significantlyover time, but there were no group-by-time interactions. Habitual gait speed

(P

0.053) and 6-min walk (P

0.06)showed a trend toward improvementover time. Physiological and health statusdid not significantly change after theintervention.

Participants with poorer QOL im-proved balance the most (P 0.023). Bycontrast, increased maximal gait speedwas associated with better baselinehealth, muscle function, and exercise ca-pacity. Following stepwise regression,lower baseline blood glucose and %BF in-dependently predicted improved maxi-mal gait speed (r 0.71, P 0.0001),

accounting for 65% of the variance.Improvements in balance index (r

0.34, P 0.047) and gait speed (maximalgait speed: r 0.46, P 0.008; habitualgait speed: r 0.44, P 0.011) weresignificantly correlated with compliancebut neither were related to each other(P 0.90) nor could they be explained bychanges in physiological or health status.

CONCLUSIONS Wereport for thefirst time the novel and robust relation-ships between muscle power and contrac-

tion velocity and mobility impairment intype 2 diabetes.Muscle contraction veloc-ity was the single characteristic indepen-dently associated with poorerbalance andgait in this cohort.

After 4 months, Tai Chi providedmodest significant improvements in mo-bility, although not different from shamexercise. The dose and/or movements ofthe Tai Chi for Diabetes program may nothave been sufficient to elicit robust adap-tations. Furthermore, the high prevalenceof obesity and osteoarthritis may havecompromised an optimal training style.

Table1Baselinecharacteristicsofparticipantsandoutcomes

afterTaiChiandshamexercise

Characteristic

TaiChi(n

17)

Shamexercise(control)(n

18)

Change

overtime

P

value

Group

effect

P

value

Baseline

Follow-up

%change

Baseline

Follow-up

%change

Age(years)

65.9

7.4

64.9

8.1

Durationofdiagnosedty

pe2diabetes(years)

8.5(025)

9.0(0.750)

Numberofcomorbidities

6.9

6.7

6.1

8.8

Cognition(030)*

28(2530)

27(2330)

Weight(kg)

87.5

13.7

88.1

12.3

1.1

3.0

80.7

16.1

80.6

16.2

0.1

1.9

0.2

0.3

%BF

43.0

4.8

42.7

5.7

0.6

3.4

37.3

8.4

36.8

9.1

1.0

2.8

0.1

0.7

Waistcircumference(cm

)

106.1

14.6

108.2

13.2

0.5

3.4

98.4

12.6

98.7

12.5

0.4

2.8

0.4

0.9

Bloodglucose(mmol/l)

7.6(3.915.6)

7.5(5.712.5)

7.7

28.8

7.9(5.613.9)

7.4(5.415.4)

3.2

20.4

0.9

0.2

Dailymedications(n)

7.5

4.0

8.2

4.4

4.6

19.7

6.4

3.8

6.8

4.0

9.0

5.9

0.9

0.2

Mobility

Balanceindex()

111.1

23.1

107.3

23.1

2.5

14.9

111.5

22.2

104.1

22.2

5.8

12.6

0.03*

0.5

Singlelegstance,eyes

open(s)

8.96(0.430)

1

7.9(0.630)

47.7(79.2to3,473.2)

30(1.330)

24.2(030)

0(100to407)

0.6

0.4

Singlelegstance,eyes

closed(s)

3.9(0.419.6)

2.8(0.114.0)22.6(93.6to190.9)

2.2(0.66.0)

2.0(08.3)

2

3.1(100to730)

0.2

0.2

Tandemwalkscore

19.1

7.0

18.1

8.3

4.7

27.6

18.5

6.3

17.2

6.2

5.3

23.4

0.2

0.8

Habitualgaitspeed(m/s)

1.0

0.2

1.1

0.2

12.3

27.4

1.1

0.2

1.2

0.3

7.9

26.6

0.053

0.7

Maximalgaitspeed(m/s)

1.6

0.3

1.7

0.3

6.6

10.3

1.6

0.3

1.7

0.3

5.9

12.8

0.005

0.9

Physiologicalcapacity

Musclestrength(nmol/l)

91.3

31.5

97.8

24.8

12.9

28.9

89.7

30.3

90.7

33.8

4.9

28.1

0.3

0.5

Peakmusclepower(W

)

215.9

75.4

220.9

64.9

4.8

18.1

221.7

74.5

217.4

74.5

0.4

16.7

1.0

0.5

Peakmusclevelocity(

rad/s)

2.7

0.8

2.6

0.7

0.8

34.1

2.6

0.8

2.8

0.6

15.5

46.0

1.0

0.3

Muscleendurance(nu

mberofrepetitions)

4(213)

5.5(014)

0(100to450)

4(211)

3(014)

3

6.6(100to200)

0.5

0.5

6-minwalkdistance(m)

474.0

76.1

481.8

83.0

1.7

7.4

456.6

117.8

470.1

118.2

3.6

8.2

0.06

0.6

Valuesofnormallydistribu

teddataaremeans

SD.Nonnormallydistributeddataaremedian(range).*Cognitionwa

sassessedbytheMini-MentalStateExaminatio

n,whichusesascaleof0-30,withscores24

indicatingcognitiveimpairment(14).Significantdifferencebetweengro

upsatbaseline(P

0.020.04).%BFwasdeterminedusingbioelectricalimpedanceanalys

is(20).Balanceindex:alowerscoreindicates

betteroverallbalanceperfo

rmance(17).Tandemwalkscoreequalstime

tocompletecourseplusnumberoferrorsmadeduringthetest;alowerscoreindicatesbetterbalance.P

valuesweredeterminedbyfactorial

ANOVA.AP

valueof0.05wasacceptedasstatisticallysignificant.

Orr and Associates

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Enhanced balance and gait speed werenotrelated to each other. Compliance, how-ever, wasrelatedto improvedmobility, sug-gesting that the observed improvementscannot be solely considered a learning ef-fect. Unmeasured aspects of group partici-pation, such as changes in motor control,socialization, or neuropsychological func-

tion, may explain our results.In conclusion, mobility impairments

in an older, obese cohort with type 2 dia-betes are associated with low musclepower and may therefore respond morerobustly to an exercise intervention spe-cifically designed to improve muscle con-traction velocity, such as explosiveresistance (power) training.

Acknowledgments We thank DouglassHanly Moir Pathology for their sponsorship,Keiser Sports Health for their donation of K400

Electronics for pneumatic-resistance machines,and the participants for their dedication.

References1. Volpato S, Blaum C, Resnick H, Ferrucci

L, Fried LP, Guralnik JM: Comorbiditiesand impairments explaining the associa-tion between diabetes and lower extrem-ity disability: the Womens Health andAging Study. Diabetes Care 25:678683,2002

2. Volpato S, Ferrucci L, Blaum C, Ostir G,Cappola A, Fried LP, Fellin R, GuralnikJM: Progression of lower-extremity dis-ability in older women with diabetes: theWomens Health and Aging Study. Diabe-tes Care 26:7075, 2003

3. Bruce DGM, Davis WAP, Davis TMED:Longitudinal predictors of reduced mobili-ty and physical disability in patients withtype 2 diabetes: the Fremantle DiabetesStudy. Diabetes Care 28:24412447, 2005

4. de Rekeneire N, Resnick HE, Schwartz AV,Shorr RI, Kuller LH, Simonsick EM, VellasB, Harris TB: Diabetes is associated withsubclinical functional limitation in non-disabled older individuals: the Health,Aging, and Body Composition Study. Di-abetes Care 26:32573263, 2003

5. Brandon LJ, Gaasch DA, Boyette LW,Lloyd AM: Effects of long-term resistive

training on mobility and strength in olderadults with diabetes. J Gerontol A Biol SciMed Sci 58:740745, 2003

6. Wolf SL, Barnhart HX, Kutner NG, Mc-Neely E, Coogler C, Xu T: Reducing frailtyandfalls in older persons:an investigationof Tai Chi and computerized balancetraining: Atlanta FICSIT Group: Frailtyand Injuries: Cooperative Studies of Inter-vention Techniques. J Am Geriatr Soc 44:489497, 1996

7. Schaller KJ: Tai Chi Chih: an exercise op-tion for older adults. J Gerontol Nurs 22:1217, 1996

8. Hain TC, Fuller L, Weil L, Kotsias J: Effectsof Tai Chi on balance. Arch OtolaryngolHead Neck Surg 125:11911195, 1999

9. Christou EA, Yang Y, Rosengren KS: Taijitraining improves knee extensor strengthand force control in older adults. J Geron-tol A Biol Sci Med Sci 58:763766, 2003

10. Lan C,Lai JS, ChenSY, WongMK:Tai ChiChuan to improve muscular strength andendurance in elderly individuals: a pilotstudy. Arch Phys Med Rehabil 81:604607, 2000

11. Tsang WW, Hui-Chan CW: Effect of 4-and 8-wk intensive Tai Chi training onbalance control in the elderly. Med SciSports Exerc 36:648 657, 2004

12. Hong Y, Li JX, Robinson PD: Balance con-trol, flexibility, and cardiorespiratory fit-ness among older Tai Chi practitioners.Br J Sports Med 34:2934, 2000

13. Lan C, Lai JS, Chen SY, Wong MK: 12-month Tai Chi training in the elderly: itseffect on health fitness. Med Sci Sports Ex-erc 30:345351, 1998

14. Folstein MF, Folstein SE, McHugh PR:Mini-Mental State: a practical methodfor grading the cognitive state of patientsfor the clinician. J Psychiatr Res 12:189198, 1975

15. Lam P: Tai Chi for diabetes: designed tohelp prevent & control diabetes. In EastAction Videos. Narwee, Australia, Tai ChiProductions, 2001

16. Pu CT,Johnson MT,FormanDE,HausdorffJM, Roubenoff R, Foldvari M, Fielding RA,Fiatarone Singh MA: Randomized trial ofprogressiveresistance trainingto counteractthe myopathy of chronicheartfailure.J ApplPhysiol 90:23412350, 2001

17. Orr R, de Vos N, Singh N, Ross D, Stavri-nos T, Fiatarone Singh M: Power trainingimproves balance in healthy older adults. J Gerontol A Biol Sci Med Sci 61:7885,2006

18. de Vos NJ, Singh NA, Ross DA, StavrinosTM, Orr R, Fiatarone Singh MA: Optimalload for increasing muscle power during

explosive resistance training in olderadults. J Gerontol A Bio Sci Med Sci 60:638647, 2005

19. Guyatt GH, Sullivan MJ, Thompson PJ,Fallen EL, Pugsley SO, Taylor DW, Ber-man LB: The 6-minute walk: a new mea-sure of exercise capacity in patients withchronic heart failure. Can Med Assoc J132:919923, 1985

20. Lukaski H, Bolunchuk W, Hall C, SidersW: Validation of tetrapolar bioelectricalimpedance method to assess human bodycomposition. J Appl Physiol 60:13271332, 1986

21. Ware JE, Sherbourne CD: The MOS 36-item short-form health survey (SF-36). I.Conceptual framework and item selec-tion. Med Care 30:473483, 1992

22. Welch G, Beeney LJ, Dunn SM, SmithRBW: The development of the DiabetesIntegration Scale: a psychometric study ofthe ATT39. Multivariate Exp Clin Res 11:7588, 1996

Diabetes: mobility impairment and Tai Chi

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