28 0 7 7 1 4 4 6 2
STRENGTH, POWER AND FUNCTIONAL
ABILITY
HEALTHY
ELDERLY PEOPLE
Submitted to the University of London for the degree of Ph.D.
by
D A W N A L E X A N D R A SKELTON
University D epartm ent of Geriatric M edicine Royal Free Hospital School o f Medicine
London, United Kingdom
1995
M t UI CA L LIBRAKi ROYAL FREE HOSPITAL
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A B ST R A C T
This thesis considers five major questions. 1) What are the age-related losses o f strength, power and selected functional ability in healthy elderly people? 2) H ow strict do health criteria for "healthy” elderly people need to be? 3) Can exercise training improve strength and power in healthy elderly women? 4) Do isolated improvements in strength and power improve selected functional ability? and 6) Can "thresholds o f strength and power for maintenance o f functional ability" be identified in healthy elderly people?.
Reproducibility studies o f measurements made on the "strength chair", Nottingham Leg Extensor Power Rig, questionnaires o f social competence and physical activity and the selected functional tests showed good reliability on retest in elderly people. The health criteria used for describing "healthy" and "medically stable" elderly people and the methods used to recruit such people are discussed. 150 'healthy' and 'medically stable' men and women aged 65 to 89, meeting strict health criteria, were recruited for this cross-sectional study. Isometric strength, leg extensor power and functional ability tests (rising from a chair and from the floor, lifting a weighted bag and stepping ability) were measured. Differences in strength and power over the age range imply a loss o f 1-2% and 3V2% per annum respectively, even in health. The decline o f explosive power was greater than the decline o f knee extensor strength in men (p=0.0001) but not
significantly so in women (p=0.08). Healthy elderly men and women have little difficulty in lifting a weighted bag or rising from a low chair. Healthy men have little difficulty in rising from the kneeling position or stepping up but 19% o f women aged over 75 were unable to rise from the kneeling position and 60% o f the 75-79's and 100% o f the 80-89 year old women were unable to step 50cm. Chair rise time, kneel
rise time and step up height correlated with explosive power and knee extensor strengthh standardised for body weight and with age. Kneel rise time and step up height
correlated with habitual physical activity (p=-0.26 and 0.34 respectively). Medically stable women were weaker and less powerful per kg body weight than their healthy counterparts and so the healthy criteria are necessary to differentiate between healthy ageing and ageing effects compounded by disease. "Standard” values o f strength, poweer and selected functional ability in healthy old age have been presented and compared to a group o f hip fracture patients.
Forty healthy and medically stable women aged > 75 years, took part in a 12 week controlled, randomised study o f progressive resistance strength-training. There were training induced improvements in isometric knee extensor, elbow flexor and handgrip strength (mean 4-27%), power/kg (mean 18%), step height (2.5cm ) and time to rise from the floor (-21%). However, ten out o f tw elve functional tasks did not improve. There were no changes in weight, arm muscle circumference (skinfolds), body density, total body water or phase angle (body impedance analysis). At follow up, six months later, those who had continued in an exercise class had maintained their strength improvements better than those who had not taken part in an exercise class.
Distinct values o f strength or power necessary for maintenance o f functional ability could not be identified by simple correlation analysis, comparison o f strength and powe;r o f those able or unable to perform a given task or short term increases in strength and power or decreases in power to facilitate the crossing o f a functionally important threshold. Instead there appears to be "threshold zones". These "threshold zones" facilitate selective targeting o f people in need o f interventions to improve strength or power.
C O N TENTS:
Page Number:
C ore P ublications 13
Su pp lem en tary P ublications 14
List o f tables 15
List o f figures 20
Acknowledgements 27
Declaration and Ethical Approval 28
Abbreviations 29
Variability o f measurements 30
C H A P T E R 1: IN T R O D U C T IO N 31
Demography in old age 32
Disability in old age 33
Physical activity and muscle function in old age 35
Training in old age 41
The Physiological basis o f functional capacity 43A
Scope o f investigations 45
Choice o f techniques 46
C H A PT E R 2: H E A L T H C R ITER IA FO R A ND R EC R U ITM EN T 47 OF H E A L T H Y E LD ER LY SUBJECTS
Summary 48
Health criteria 49
Recruitment 53
Normal subjects? 61
Conclusions 64
C H A PT E R 3: V A L ID A T IO N OF EQ U IPM EN T: R E PE A T A B IL IT Y 65 ST U D IE S
Summary 66
Isometric knee extensor strength 67
C hap ter 3 continued: Page Number;
Isometric elbow flexor strength 71
Handgrip strength 72
Leg extensor power (lower limb power) 72
LEP Rig - overestimating or underestimating? 86
Habitual physical activity measured on a six point scale 93 Tokyo Metropolitan Index o f gerontology - social competence 93 Maximum activity score and adjusted activity score o f 94
habitual physical activity
Functional ability tests 96
Conclusions 98
C H A P T E R 4: ISO M ETR IC ST R E N G T H AND L O W E R LIMB 101 PO W E R IN H E A L T H Y ELDERLY PEO PLE
Summary 102
Introduction 103
Methods 107
Results 109
D iscussion 122
Conclusions 129
C H A P T E R 5: SELEC TED FU N C T IO N A L A BILITY IN H EA LTH Y 131 E L D E R L Y PE O PL E
Summary 132
Introduction 133
Methods 135
Results 140
C hap ter 5 continued: Page Number:
Discussion 157
Conclusions 165
C H A P T E R 6: C O M PA R ISO N OF ST R E N G T H , PO W ER AND 167 FU N C T IO N A L A BIL ITY OF SUBJECTS M EETIN G
TW O SETS OF H EA LTH CRITERIA
Summary 168
Introduction 169
Methods 170
Results 174
Discussion 185
Conclusions 188
C H A P T E R 7: ST R E N G T H TR AIN IN G IN H EA LTH Y ELD ER LY 189 W O M E N
Summary 190
Introduction 191
Methods 194
Results 204
Discussion 220
Conclusions 226
C H A P T E R 8: E FF E C T S OF STR EN G TH TR AIN IN G ON SE L E C T E D 227 F U N C T IO N A L A BIL ITY IN H E A L T H Y ELDERLY W O M E N
Summary 228
Introduction 229
C hap ter 8 continued: Page Number:
M ethods 231
Results 236
D iscussion 249
C onclusions 255
C H A P T E R 9: T H R E SH O L D S OF STR EN G TH AND PO W E R FO R 257 M A IN T E N A N C E OF FU N C T IO N A L A BIL ITY
Summary 258
Introduction 261
"Thresholds" o f strength and power necessary for maintenance o f selected 266 functional ability tasks
A nalysis 1- Correlation between strength, power and function 268 A nalysis 2 - Comparison o f strength and power between those able 272
and unable to perform a task
A nalysis 3 - Identifying a "threshold zone" 276
Conclusions 285
Decreasing power to simulate the crossing o f a functionally important 288 threshold o f power- Muscle cooling and leg extensor power
Pilot Study 1: Is the cooling induced reduction in muscle power due 289 to a cold-induced impairment o f sensory function?
Pilot study 2: Effect o f a specific cooling protocol on muscle 291 temperature
Conclusions 295
Increasing strength and power with training to simulate the recrossing o f a 297 functionally important threshold
C onclusions 297
A llied Dunbar National Fitness Survey (ADNFS) 299
C hap ter 9 continued: Page Number;
Comparison o f functional ability o f healthy elderly people with 300 strength or power below the ADNFS suggested thresholds
Conclusions 305
Conclusions 306
C H A P T E R 10: C O N CLU SIO N S AND FU TU R E W O R K 309
Recruitment o f healthy elderly people 310
Strength and power o f healthy elderly people 310
Functional ability o f healthy elderly people 311
The use o f "ideal" values o f strength, power and functional ability 313 The relationship between strength, power and functional ability - "thresholds" 314
Are healthy or medically stable subjects needed ? 317
Strength and power training in healthy old age 318
Can isolated increases in strength and power allow the re-crossing o f a 319 functionally important threshold ?
Can cooling o f muscles artificially speed up the crossing o f a functionally 321 important threshold ?
Conclusion 322
R E FE R E N C E S 323
A P PE N D IC E S: 349
ONE 351
A. Texts o f Core Publications 352
B. Texts o f Supplementary Publications 399
TWO 439
A. Health Questionnaire 440
B. H, Health Criteria 443
A p p en d ix 2 continued: Page Number:
THREE
FOUR
C. Health Criteria D. Press release
E. Statistical methods used in this thesis F. IKES data on 2 occasions (elderly subjects) G: Norm alised data for each block position
on the footplate (LEP Rig), young subjects H. Leg extensor power data on two occasions
(elderly subjects)
I. D erived power output from torque/velocity data from Klitgaard et al. (1990)
A: Consent Form
B: Activity questionnaire
C: Social competence questionnaire D: Functional ability test protocols
A: Consent form
B: Exercise prescription form
C: Exercise diaries for the training and control group
D: Resistance Exercises used E: The Habitual Activity Profile
questionnaire
F: Functional ability test protocols G: Uncontrolled training studies which have
considered muscle strength.
H: Controlled (non randomised) training
studies which have considered muscle strength.
444 445 446 455 457 458 460 461 462 463 464 465 469 470 471 472 479 506 512 516 521
A p p en d ix 4 continued: Page Number:
I: Randomised controlled training studies 525
which have considered muscle strength.
J: Uncontrolled training studies which have 530
considered muscle power.
K: Controlled training studies which have 531
considered muscle power.
L: Uncontrolled training studies which have considered 532 muscle strength and funcitonal ability.
M: Controlled (but not randomised) training studies 533 considering muscle strength and functional ability.
N: Controlled, randomised training studies which have 534 considered muscle strength and functional ability.
FIVE 536
A. Habitual physical activity (per week) as 537
defined by the Allied Dunbar National Fitness Survey compared to the grades o f activity in healthy men and women measured using the Grimby activity score
B. Percentage o f healthy men and women 538
and o f the sample o f men and women from the ADNFS with activity levels below the level needed for continued health
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C O R E PU BLIC A TIO N S;
FULL PAPERS:
S K E L T O N , D.A., C.A. GREIG, J.M. DAVIES and A. YOUNG. Strength, power and related functional ability in healthy people aged 65-89 years. Age A geing 23:371-377 (1994).
S K E L T O N , D.A., A. YOUNG, C.A. GREIG and K.E. MALBUT. Effects o f resistance training on strength, power and selected functional abilities o f women aged 75 and over. Accepted for publication (J. Am. Ger. Soc) 1995.
SK E L T O N , D.A., A. Y O U N G and C.A. GREIG. A comparison o f strength, power and related functional ability o f women aged 65 to 89 years selected according to two sets o f health criteria. In preparation. 1995.
ABSTRACTS:
SK E L T O N , D.A., C.A. GREIG, J.M. DAVIES and A. YOUNG. M uscle function in healthy women aged 65 to 84. Med. Sci. Sports Exerc. 24: S75 (1992).
SK E L T O N , D.A., C.A. GREIG, J.M. DAVIES and A. YOUNG. M uscle function in healthy men aged 65 to 84. Age A geing 21: P8 (1992).
SK E L T O N , D .A . and A. YOUNG. Are the National Fitness Survey strength and power thresholds for performance o f everyday tasks too high? J. P h ysio l 473:84P (1993).
S K E L T O N , D.A., C.A. GREIG, K. MALBUT and A. YOUNG. M uscle strength and power after strength-training by women aged 75 and over: a randomized, controlled study.
J. P h y sio l 473.83P (1993).
S K E L T O N , D.A., C.A. GREIG, K.E. MALBUT and A. YOUNG. D oes increased strength and power improve functional ability in healthy elderly women? Clin. Sci.
86:27P (1993).
SU PPL E M E N T A R Y PU B L IC A T IO N S:
FULL PAPERS:
GREIG, € ., F. BUTLER, D. SK ELTO N , S. M AHM UD and A. Y O U N G Treadmill walking in old age may not reproduce the real life situation. Journal o f the American G eriatrics Society 41: 15-18 (1993).
Y O UNG , A., J. BOTELLA, C.A. GREIG and D .A . SKELTO N. Functional performance assessment in old age. In: Harris, S., Suominen, H., Era, P., Harris,W.; eds. Physical Activity, A ging and Sports III. Towards healthy aging - International perspectives. P art I. P h ysiological and biom edical aspects. Centre for the Study o f Aging, Albany, N ew York: 149-160 (1994).
GREIG, C.A., A. YOUNG. D A . SK ELTO N , E. PIPPET, F.M.M. BUTLER and S.M. M AHM UD. Exercise studies with elderly volunteers. A ge Ageing, 23:185-189 (1994).
Y O U NG , A. and D.A. SK E L T O N Applied physiology o f strength and power in old age.
Int. J. Sports Med. 15(3): 149-151 (1994).
LEVY, D.I., A. YOUNG, D A . SK E L T O N and Y. AI-LYN. Strength, power and functional ability. In: Passed, M.; ed. G eriatrics '94. International Association o f G erontology (I.A.G.) European Region: C linical Section Congress. CIC Edizioni Intemazionali, Florence: 85-93 (1994).
SMITH, R., O. SCOTT, A. Y O U N G and D A . SK E L T O N . An investigation into hip muscle strength and function in very elderly women. In preparation.
ABSTRACTS:
S K E L T O N D .A ., H. ASTON, C.A. GREIG and A. YOUNG. Effect o f cooling on the power o f voluntary and electrically stimulated contractions o f the lower limb extensors.
Clin. Sci. 83 (suppl 27): 16P (1992).
LIST OF TA BLES:
Page Number:
C hapter 2:
Table 1: Number o f volunteers responding to different methods o f 55 recruitment, to October 1993 (all health criteria).
Table 2: The health (according to the two sets o f criteria) o f the 56 975 people on the recruitment database.
T able 3: Studies which have used the database for volunteers. 63
C hapter 3:
Table 4: Coefficients o f Variation on test re-test o f isometric knee 70 extensor strength (elderly subjects) .
Table 5: Effect o f age on coefficients o f variation on test re-test 70 o f isometric knee extensor strength (elderly subjects).
Table 6: Normalised data for each block position on the footplate 78 (LEP Rig), young subjects.
Table 7: Mean, SD and CV for the aB block position on the 80 footplate (LEP Rig) - five visits, young subjects.
Table 8: Mean, SD and CV for the bB block position on the 82 footplate (LEP Rig) - five visits, young subjects.
Table 9: Coefficients o f Variation on test re-test o f leg extensor 84 power (elderly subjects).
Table 10: Effect o f age on coefficients o f variation on test re-test 85 o f leg extensor power (elderly subjects).
Page Number: C h ap ter 4:
T ab le 11: Physical characteristics o f subjects. 110
T ab le 12: Reference values for strength and power in healthy elderly 115 people.
T ab le 13: Relationships o f strength and power with age. 116 T ab le 14: A comparison o f strength, power and ability to lift a weighted 120
bag - healthy men and women and hip fracture patients
C hap ter 5:
T ab le 15: Correlation coefficients for relationships o f strength, power, 142 weight and age with functional ability in healthy men
and women.
T ab le 16: Stepping up ability in healthy men and women. 144 T able 17: Correlation coefficients for relationships o f age and 148
habitual physical activity with functional ability in healthy elderly people.
T ab le 18: Interrelationships between functional ability tasks in healthy 151 elderly people.
T able 19: Stepping up ability in elderly women - a comparison between 160 studies
C h ap ter 6:
T able 20: Principal differences between the two sets o f exclusion 171 criteria.
T able 21: Characteristics o f subjects. 175
T able 22: Strength and power o f H| and women. 176
T able 23: Relationships o f strength and power with age in and 178 H2 women.
T able 24: Stepping up ability in H, and Hj women. 183
Page Number: C h ap ter 6 continued:
T able 25: Correlation coefficients for relationships o f strength, power 184 and age with functional ability in H, and H2 women.
C hap ter 7:
T able 26: Anthropometry pre- and post-training in the training and 207 control group.
T able 27: Strength and power in the training and control group after 208 12 weeks o f training.
T able 28: Effect o f number o f exercise sessions attended, age habitual 213 physical activity and on mean % changes in strength and
power in the training group.
T able 29: Mean strength as a percentage o f visit 1 (pre-training) in 217 strength and power at visit 2 (post-training) and visit 3
(follow-up) in the training group
T able 30: Mean % difference in strength and power between visit's 2 218 and 3 in volunteers who took part in a class after the study
and those who did not.
C hap ter 8:
T able 31: Pre- and post-training measurements o f functional ability 238 in the training and control group.
T able 32: Percentage change in functional ability over the training period 239 in the training and control group.
T ab le 33: Effect o f number o f exercise sessions attended and age on 244 mean % changes in functional ability in the training group.
T ab le 34: Relationships o f strength and power standardised for body 245 weight with functional ability pre- and post-training in the
training group.
Page Number: C hap ter 8 continued:
T able 35: Median % change from visit 1 (pre-training) in functional 247 ability at visit 2 (post-training) and visit 3 (follow-up).
T able 36: Median % difference in functional ability between visits 2 248 and 3 in volunteers who took part in a class after the study
and those who did not.
C hap ter 9:
T able 37: Information on the subjects used for possible identification 267 o f thresholds o f strength and power necessary for
maintenance o f functional ability.
T able 38: Correlations for strength and power standardised for body 269 weight with chair rise time, kneel rise time, step up height,
weight lifted in a bag and stair climbing ability and in healthy elderly people and hip fracture patients.
T able 39: The age, step up ability, strength and power standardised for 273 body w eight o f those healthy and medically stable people able and unable to rise from the kneeling position on the floor.
T able 40: A ge, IKES/kg and LEP/kg o f healthy and medically stable 275 elderly people who could and could not manage 30, 40
and 50 cm step up height.
T able 41: The chair rise time (in distinct bands o f <1, <2 or >2 seconds) 277 and LEP/kg (divided into distinct bands o f 0.25 W/kg) o f
healthy and medically stable men and women (n=199).
T able 42: Statistical power o f the muscle cooling and leg extensor 291 power study.
T able 43: Number o f healthy men and women vyith muscle strength or 302 power below ADNFS suggested thresholds. Expressed as
% o f sam ple in each age group and gender.
Page Number: C hap ter 9 continued:
T able 44: Functional ability o f healthy men and women who fail 304 below ADNFS suggested thresholds for strength and power.
E xpressed as % able to perform task.
LIST OF FIGURES:
C hap ter 1:
F igure 1: Percentage o f elderly population living alone {adapted from Wallis, 1991).
Figure 2: A ctive life expectancy (adapted from Katz, Branch, Branson, Papsidero, Beck and Greer, 1983).
Page Number:
33
43
C hap ter 2:
Figure 3: Advert used in recruitment o f subjects. 53
Figure 4: Histogram o f the ages o f healthy (H J and medically 57 stable (H^) men and women on the database.
C hap ter 3:
Figure 5: The 'Strength Chair' used to measure isometric knee 68 extensor strength (IKES) and isometric elbow flexor strength (lEFS).
{A dapted from E dw ards et a l, 1977)
Figure 6: Isometric knee extensor test re-test data - 69 men and women.
Figure 7: IKES test re-test data - men and women. 69
Figure 8: The Nottingham Leg Extensor Power Rig. 74
Figure 9: Block positions on the footplate (LEP Rig). 76 Figure 10: Leg extensor power test re-test data - men and 85
women.
F igure 11: Leg extensor power test re-test data - men and 86 women.
Figure 12: The effect o f velocity on knee extensor torque and 88 derived power in young adults (Klitgaard et al., 1990).
Figure 13: LEP output trace - healthy female aged 32. 89
Page Number: C hap ter 3 continued:
Figure 14: LEP output trace - hip fracture patient aged 85. 89 Figure 15: Knee angle change (deg/s) during LEP measurement 92
on LEP Rig.
C hap ter 4:
Figure 16: Isometric knee extensor strength o f the healthy men 112 and women across the age range.
Figure 17: Isometric knee extensor strength standardised for body 112 weight o f the healthy men and women across the age
range.
Figure 18: Lower limb power o f the healthy men and women across 113 the age range.
Figure 19: Lower limb power standardised for body weight o f the 113 healthy men and women across the age range.
Figure 20: Standardised lower limb power and isometric knee 114 extensor strength over the age range for healthy elderly
men and women.
Figure 21: Leg extensor power standardised for body weight in healthy 121 elderly people and hip fracture patients
Figure 22: Isometric elbow flexor strength in healthy elderly people 121 and hip fracture patients
C hapter 5:
Figure 23: Subject rising from a low, armless, chair. 136 Figure 24: Subject lifting a weighted bag onto a fixed height shelf. 137 Figure 25: Subject stepping up onto a 30cm box, without the use 138
o f handrails.
Page Number; C hap ter 5 continued:
Figure 26: Subject rising from the kneeling position on the floor, 139 without the use o f handholds.
Figure 27: E ffect o f LEP/kg on chair rise time in healthy men and 141 women.
F igure 28: Effect o f age on chair rise time in healthy men and 143 women.
Figure 29: Effect o f age on stepping up ability in healthy men and 143 women.
F igure 30: Effect o f LEP/kg on stepping up ability in healthy men 145 and women.
Figure 31: Effect o f body height on stepping up ability in healthy 145 men and women.
Figure 32: Effect o f age on kneel rise time in healthy men and 147 women.
Figure 33: Effect o f LEP/kg on kneel rise time in healthy men 147 and women.
F igure 34: Effect o f habitual physical activity on chair rise time 149 in healthy men and women.
F igure 35: Effect o f habitual physical activity on stepping up 149 ability in healthy men and women.
F igure 36: E ffect o f habitual physical activity on kneel rise time 150 in healthy men and women.
Figure 37: The relationship between kneel rise time and chair rise 150 time in healthy men and women.
Page Number: C hap ter 6;
F igure 38: Kneel rise time - histogram o f number o f healthy and 172 medically stable subjects measured.
Figure 39: Isometric knee extensor strength standardised for body 179 weight -healthy and medically stable women.
Figure 40: Leg extensor power standardised for body weight - 179 healthy and medically stable women.
Figure 41: Chair rise time in H, and H2 women. 181
Figure 42: Kneel rise time in H, and women. 181
Figure 43: Kneel rise time and LEP/kg in Hj and H2 women. 182
C hap ter 7:
F igure 44: The exercise class in progress. 201
Figure 45: The resistance o f 'Thera-band' - single strand. 202 Figure 46: The resistance o f 'Thera-band' - loop. 202 Figure 47: Isometric knee extensor strength pre- and post-training 209
in the training and control group.
Figure 48: Isometric elbow flexor strength pre- and post-training 209 in the training and control group.
Figure 49: Isometric handgrip strength pre- and post-training in 210 the training and control group.
Figure 50: Mean % change in IKES, lEFS and LEP/kg in the 210 training and control group.
Figure 51: Leg extensor power pre-and post-training in the 211 training and control group.
Figure 52: Effect o f age on training improvements in IKES, lEFS 214 and LEP in the training group.
Figure 53: Effect o f habitual physical activity on training 214 improvements in IKES in the training group.
Page Number: C hap ter 7 continued:
F igure 54: Isometric knee extensor strength o f the training 216 group pre- and post-training and 6 months post-training.
F igure 55: Isometric knee extensor strength o f the training group 219 at Visits 1, 2 and 3 in those who took part in an exercise
class and those who did not.
C hap ter 8:
F igure 56: Pre- and post-training stair-climbing data for the training 237 group.
F igure 57: Pre- and post-training corridor step data in the training 240 group.
F igure 58: Pre- and post-training fast chair rise data in the training 240 group.
F igure 59: Pre- and post-training normal kneel rise time data in the 241 training group.
Figure 60: Stepping up ability pre- and post-training in the control and 243 training group.
C hap ter 9:
F igure 61: Effect o f age on the estimated percentage o f a maximal 261 voluntary contraction (% MYC) o f the quadriceps muscle
required to raise a healthy woman from a low, armless chair, {adapted from Young, 1986).
F igure 62: Schematic representation o f thresholds o f exercise 262 performance necessary for maintenance o f functional ability.
Figure 63: The four phases o f functional decline {adapted from 264
Svanborg, 1988).
Page Number: C hapter 9 continued:
Figure 64: Kneel rise time and LEP/kg in 143 healthy and medically 271 stable men and women.
F igure 65: Ability to lift a weighted bag and lEFS in hip fracture patients. 271 F igure 66: LEP/kg in healthy and medically stable elderly people 273
aged 65 to 89 who are able and unable to rise in less <3 seconds.
Figure 67: The percentage o f healthy men and women rising from a lo w 276 chair in <1, <2 or >2 seconds.
Figure 68: The percentage o f young old (65 to 77 years) and old old (78 279 to 98 years) able to rise out o f a low chair in <2 seconds.
Figure 69: The percentage o f young old (65 to 77 years) and old old (78 279 to 98 years) able to rise out o f a low chair in <1 seconds.
Figure 70: The percentage o f healthy men and women rising from the 281 kneeling position on the floor in <2, <3 or >3 seconds.
Figure 71: The percentage o f healthy and medically stable men and 281 women and hip fracture patients able to lift 4 or 6 kg bags
onto a shelf.
Figure 72: The percentage o f healthy and medically stable women able 282 to manage 4, 5 or 6 flights o f stairs.
F igure 73: LEP/kg and percentage o f healthy and medically stable 283 men and women stepping up 30, 40 or 50 cm.
F igure 74: The age and percentage age o f healthy and medically stable 284 elderly people stepping up 30, 40 and 50 cm.
Figure 75: The percentage o f young old (65 to 77 years) and old 284 old (78 to 98 years) able to step 30cm.
Figure 76: The thermocouple used for muscle temperature. 292 Figure 77: Placement o f the muscle temperature thermocouple. 293 Figure 78: Ear, skin, oral and muscle temperature before, during and 294
after cooling.
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A C K N O W L E D G E M E N T S;
My first thanks must be to Professor Archie Young for his inspiring and constant support and supervision throughout the performance o f this work and the preparation o f the thesis. I am grateful to all those with whom I worked, particularly the co-authors o f the
publications on which this thesis is based. In particular my thanks to Dr Carolyn Greig for her constant support, supervision and friendship, even over long distances, and Professors Don Grieve and Shah Ebrahim for their help whenever asked. The studies described in my thesis were carried out while working at the Royal Free Hospital in the university departments o f Geriatric Medicine and Anatomy. The number o f colleagues to whom I am indebted is therefore very large indeed. I would like to thank a few
personally - Dr Tracey Wilkinson, Thais de lima Resende, Dr George Gioftsos, Dr David Levy, Dr Ann Davies and Katie Malbut.
I am indebted to the Medley Trust who sponsored my research through Research Into A geing and to all at Research Into Ageing for their constant support and assistance throughout my studentship. I am extremely grateful to my father, Alan Skelton, for his tireless and generous help with the enormous amount o f clerical and computer input work involved with recruiting this number o f subjects. I am also grateful to Patricia Labro for her patience and help with the volunteers, to Caroline Sabin for her expertise in Statistics, to Susie Dinan and Tony Lycholat for their help in choosing safe exercises for older people, to Miss Ellis for her help/advice on procedures as regards this thesis and to all the volunteers who offered their time so freely and enthusiastically to take part in the various studies. My thanks to my friends Allison and D om inic who were very supportive and understanding, and F.J.Samuely and Partners who allowed me use o f a photocopier.
My greatest debt and love is, as always, to my family - my parents, Alan and Helen Skelton, to my partner Peter Osborne and all the Osborne household, my grandparents, Gladys and Agnes (and William and John in spirit), and my aunts, uncles and cousins, for their love, forbearance, encouragement and constant reiteration that I could do it!.
D E C L A R A T IO N ;
I declare that this thesis has been composed by m yself and the books and papers cited were all consulted by me personally, except where it is otherwise stated.
The experimental work described in the 'Core Publications' (Appendix lA ) was all carried out by m yself or under my direct supervision. The 'Core Publications' were written by me. All other studies or papers described in the 'Supplementary
Publications' (Appendix IB) were not carried out or written by m yself, but had my input as a joint supervisor or author.
I declare that the work in this thesis, except where indicated, is original work and that this thesis has been written solely by Dawn Skelton.
signed:
Professor Archie Young, Head o f Department, University Department o f Geriatric Medicine, Royal Free Hospital School o f Medicine.
E T H IC A L A PPR O V A L :
All studies in this thesis were conducted with the approval o f the Hampstead Health Authority Ethical Practices Sub-committee and all subjects gave written informed consent (see Appendices 3 A and 4 A)
ABBREVIATIONS:
%7 7p.a. The slope o f the regression line expressed as the percentage o f the interpolated value at the mid-point o f the age range (age 77) 'lost' per annum
IRM One repetition maximum 95% C.I. 95% Confidence Interval AAS Adjusted Activity Score ADL Activities o f daily living
ADNFS Allied Dunbar National Fitness Survey ESI British Standards Institute
CSA Cross-sectional area CV Coefficient o f variation Hj Healthy (subjects)
Medically Stable (subjects) HAP Habitual Activity Profile HGS Handgrip strength
lA D L Instrumental activities o f daily living IKES Isometric knee extensor strength
IKES/kg Isometric knee extensor strength standardised for body weight lEFS Isometric elbow flexor strength
IsoM Isometric
IsoK Isokinetic
LEP Leg extensor power (lower limb power)
LEP/kg Leg extensor power standardised for body weight MAS Maximum Activity Score
MVC Maximal voluntary contraction MVP Maximal voluntary power NS Not statistically significant
p.a. Per annum
SD Standard deviation
SP Stimulated power
TMIG Tokyo metropolitan index o f gerontology - social competence VOjmax Maximal rate o f oxygen uptake during voluntary physical activity
V A R IA B IL IT Y OF M E A SU R E M E N T S:
Full details are given in Chapter 3 o f this thesis. All coefficients o f variation figures and the kappa statistic for step up height and lifting a weighted bag were obtained from measurements on healthy and medically stable men and women aged between 65 and 89 years. The activity and social competence questionnaire kappa statistics were obtained from measurements on healthy and medically stable women aged 75 to 79 years.
Coefficient o f Variation
Isometric knee extensor strength 6% Isometric elbow flexor strength 6%
Handgrip strength 3%
Lower limb extensor power 7% Timed rise from a low chair 9% Timed rise from the floor 7%
Kappa Statistic
Step up height 0.45
Lifting a weighted bag 1.0
Activity Questionnaire 0.33
Maximum Activity Score 0.75
Adjusted Activity Score 0.56 Social competence Questionnaire 0.58
Strength o f agreement (kappa statistic): 0.21 to 0.40 fair; 0.41 to 0.60 moderate; 0.61 to 0.80 good; 0.81 to 1.00 very good.
CHAPTER 1
INTRODUCTION;
Demography in old age Disability in old age
Physical activity and muscle function in old age Training in old age
Scope o f investigations
INTRODUCTION:
DEMOGRAPHY IN OLD AGE
The proportion o f elderly people in the population is increasing. In the United Kingdom in 1990 there were approximately five people o f working age for every person aged over 65. By the year 2030 this ratio is predicted to decline to three people o f working age for every one over 65 (W allis, 1991). It is particularly the number o f very elderly people (those over 75 years) surviving in the population that is o f concern. In 1990 there were 3.7 million people aged over 75 and this is predicted to rise by 30% to 4.8 million by the year 2023 (Wallis, 1991). Men die earlier than women and the difference has widened since the middle part o f this century (Fox, 1988). As a result men tend to be married at the time o f death, whereas wom en tend to be widowed. This has implications for the family support available in periods o f chronic ill-health or dependence that occurs shortly before death. Single men and women are more likely to enter institutions than widowed or married people o f the same age (Fox, 1988). 4% o f the population over 65 and 8% o f the population over 75 are living in some form o f residential care (Green, M ilne, Rauta, Eldridge, W ilmot and Levy, 1989). Many older people live alone and need to care for them selves for as long as possible (Figure 1). The percentage o f elderly women using public transport on their own declines from over 70% to under 20% between the ages o f 65 and over 85 (Wallis, 1991; Brooks, Ruffell- Smith and Ward,
1974) and this suggests that many older women are becom ing housebound and may eventually need help with tasks both outside and in the home.
Figure 1: Percentage o f elderly population living alone {adapted from Wallis, 1991)
W O M E N
I I
65-59
70-74
75-79
80-84
85+
Age (years)
D ISA B IL IT Y IN OLD AGE
Elderly people, as a group, make the heaviest demands on health and social services. The average cost per person in 1986 being £1,475 for those over 75 years old (K ellie and Brody, 1990). Problems arise not only from ill health, but from declining physical function, such as walking ability, necessitating help. The most common response from the health care professional is to provide equipment to make life 'easier'. This, however, allows muscles to stay weak and the "spiral o f disuse" gets worse (Young, 1987). A more reasoned approach would be to perform an assessment o f lower limb strength and, if appropriate, implement an appropriate
strengthening programme (Young, 1987).
"When man grows old, his bones become brittle, his flesh sags,
his breathing is laboured." Yellow Em peror's Classic o f Internal M edicine Approx 2500BC, source: O xford Companion to Medicine, 1986.
Both dependency and ailments that accompany old age have long been considered inevitable. "Five geriatric giants" (originally noted by Bernard Isaacs some 20 years earlier) were seen in 75 year olds living in Glostrup (NORA) and thought to lead to dependency in old age (Schroll, 1992). They were:
1) Immobility: 51% o f men and 58% o f women were unable to m ove around indoors without the help o f another person or a cane;
2) Instability: 18% o f men and 33% o f women had dizziness or fell in a period o f a year;
3) Intellectual score: 13% o f men and 14% o f women had a score below 11 on the Raven test (a test o f intelligence);
4) Incontinence: 16% o f men and 26% o f women are partially or wholly incontinent;
5) latrogenesis: 55% o f men and 68% o f women take some form o f medications every day.
In a longitudinal study on ageing and health, those with no clinically diagnosed chronic disease constitute a minority o f older people, varying from 2% o f 80-89 year olds to 8-9% o f 70 to 79 year olds (Jylha, Jokela, Tolvanen, Heikkinen, Heikkinen and Koskinen, 1992).
Disability is common in old age. The Office o f Population Censuses and Surveys (OPCS) Disability Surveys o f 1984/5 found the prevalence o f the most severe levels o f disability to be 133 in 1,000 among people aged 80 years or over, compared with 3 per 1,000 for adults under 50 (Martin, Meltzer and Eliot, 1988).
"Exercise o f some kind or other is almost essential to the
preservation o f health in persons o f all ages - but in none
more so than in the old" D aniel M aclachlan 1863
'The Diseases a n d Infirm ities o f A dva n ced Life'.
PHYSICAL ACTIVITY AND MUSCLE FUNCTION IN OLD AGE:
Physical inactivity can be due to disease or disability but can be a risk factor in it's own right. Bassey et al. (1988; 1982) and others (Rantanen, Parkatti and
Heikkinen, 1992; Sandler, Burdett, Zaleskiewicz, Sprowls-Repcheck and Harwell, 1991), have tentatively concluded that a high level o f customary activity might help protect against some o f the age-related loss o f muscle mass or performance. The benefits o f exercise on health are well documented (Fentem, 1992; Fentem, Bassey
and Turnbull, 1988; Bassey, 1986; Shephard, 1990; Shephard and Montelpare, 1988; H ollos2y , 1983; Bassey and Hall, 1985). Branch (1992) found that women aged 65 and older, who reported having slowed down their activities, were tw ice as likely to have functional disabilities five years later.
"That which is used develops and that which is not used wastes away."
Hippocrates. Source: Physical Activity: Human Growth and Development.
The relationship between physical activity and muscle strength in older adults is controversial; most agree that there is a relationship between inactivity and muscle weakness but is it causal?, what comes first - a decline in activity leads to muscle strength loss or a loss o f muscle strength leads to a slowing o f physical activity? Som e studies relate inactivity to age-related decline (Clement, 1992; Aniansson, Grimby and Rundgren, 1980), and others fail to support this (Kallman, Plato and Tobin, 1992). The loss o f muscle strength with age is believed by som e to be slow ed by increasing physical activity (Era, Lyyra, Viitasalo and Heikkinen, 1992; Sipila, Viitasalo, Era and Suominen, 1991; Schilke, 1992; Laforest, St-Pierre, Cyr and Gayton, 1992). For some elderly people muscular strength and power may determine their choice o f physical activity and the intensity with which they can undertake that activity (Bassey and Hall, 1985; Sandler, Burdett, Zaleskiewicz, Sprowls-Repcheck and Harwell, 1991).
Just how much o f muscle weakness is due to ageing alone (without the presence o f disease) is unknown. Most studies that have considered muscle function in old age have examined subjects with varying degrees o f disease or have not documented the medical history o f the volunteers. Therefore, it is not certain if the loss o f muscle function in old age is inevitable or a consequence o f weakness due to the effects o f disease or illness. Cross-sectional studies (for review - Young, 1988) o f both healthy subjects (although not by strict standards) and subjects with various pathologies have shown rates o f loss o f strength o f ~1.5% p.a.. Two longitudinal studies have shown similar rates o f loss o f strength (Aniansson, Hedberg, Henning and Grimby, 1986; Aniansson, Sperling, Rundgren and Lehnberg, 1983). Greig et al., in their small longitudinal study, however, showed a non-significant loss o f IKES o f only 0.3%^ggn start 8ge per annum (p.a.) (Greig, Botella and Young, 1993). Their healthy over-80-year-old subjects had all maintained or increased their activity levels over the eight year period. Their subjects' high levels o f habitual physical activity may explain their unexpectedly slow rate o f decline o f muscle strength. Greig also speculated that an unusually slow rate o f loss o f strength (whether intrinsic or acquired) might be a favourable risk factor’ for "successful ageing" (Rowe and Kahn, 1987).
"The essential service o f muscle to life is, quickly and reversibly, to
shorten so as to pull"...."The importance o f muscular contraction to
us can he stated by saying that all man can do is to move things, and
his muscular contraction is his sole means thereto."...
Charles Sherrington The Gifford Lectures 1937/8.
Source; Man on his nature, Cambridge University Press, 1963.
There have been no studies considering explosive muscle power (a measure o f strength and speed o f the muscle) in healthy elderly people. M ost forms o f exercise make use o f muscular power. In exercise o f short duration (1 second or less) the maximum power output depends on the mass o f the muscle, its contractile properties (in particular its force-velocity curve) and the matching o f the load to the muscle. Falls in the over 75’s account for 82% o f all accidental domiciliary deaths (Wallis,
1991) and decreasing muscle power with age has been linked to the increased prevalence o f falls (Young, Botella, Greig and Skelton, 1994; Bassey and Short,
1990). W omen are much less powerful than men, and this may explain the greater prevalence o f falls amongst women. Hip fractures, due to falling, increase markedly during wintertime and this may be due to a decrease in power due to cold weather and insufficiently heated homes (Chapter 9).
A ge brings with it reductions in strength, power and maximum oxygen uptake, so that some everyday tasks require maximal effort for their performance. It then needs only a minor intercurrent illness to render an elderly person unable to perform such tasks without assistance (Young, 1986). There is a good case for using both standard ergonometry and tests o f functional ability in studies with elderly people, since they provide complementary information. Although tests o f functional ability do not usually feature in exercise test protocols, they are essential in the over 70's, since it is their ability to perform in the home, rather than in the laboratory, which is o f primary concern and because one need not reflect the other. Laboratory measures may not be representative o f the "real-life" situation. Greig et al. showed that
elderly subjects had higher heart rates during treadmill walking than during corridor walking at the same speed (mean 6 beats per minute) and the difference increased when a mouthpiece was worn on the treadmill (Greig, Butler, Skelton, Mahmud and Young, 1993).
In the presence o f pathology, reasonably strong associations have been demonstrated between functional abilities and both strength (Hyatt, Whitelaw, Bhat, Scott and M axwell, 1990) and power (Bassey, Fiatarone, O'Neill, Kelly, Evans and Lipsitz, 1992). In healthier subjects, however, the ability o f 80 years olds to climb up and down different step heights bore only a tenuous relationship to measurements o f quadriceps strength (Danneskiold-Samsoe, Kofod, Munter, Grimby, Schnohr and Jensen, 1984). Large numbers o f healthy elderly people are at or near important strength-related thresholds and so have either lost or are in danger o f losing the ability to perform some important everyday tasks (Young, 1986; 1988; 1992). Although Bassey has suggested a threshold value o f power standardised for body weight necessary to climb stairs, or rise o ff a low chair, in frail, institutionalised, elderly people (Bassey, Fiatarone, O'Neill, Kelly, Evans and Lipsitz, 1992),
"thresholds" o f strength and power necessary for performance o f everyday tasks by healthy elderly people have yet to be identified (Young, 1986; Young, 1992).
The Allied Dunbar National Fimess Survey (A DN FS) report is the largest population study o f fitness and ability in the United Kingdom (Anonymous, 1992^. It measured quadriceps and handgrip strength and leg extensor power in children and adults from
different parts o f the country. At the time o f the survey there was, and indeed still is, a paucity o f data relating to thresholds o f muscle strength necessary. The ADNFS suggested threshold levels o f strength and power necessary to perform
selected tasks (walking up stairs and rising from a low chair). The survey found that 50% o f women aged over 55 years have lower power per kg body weight (LEP/kg) than the suggested threshold and 50% o f women aged 65 to 74 have isometric knee extensor strength per kg body weight (IKES/kg), o f their dominant leg, below the suggested threshold. This gives a rather bleak picture o f the nations abilities but although field tests o f functional ability were carried out, at the time o f this thesis, the results had not been published and so it was not possible to correlate the strength and power findings with the functional tests measured. The data obtained
throughout this thesis suggest that the ADNFS suggested thresholds need validating in both healthy elderly people and people with disease (see Chapter 9).
There are many different ways to measure functional ability. Measures o f
functional ability range from self-reporting questionnaires to objective measurements o f specific tasks. According to the General Household Survey (GHS) o f 1986 over 12% o f men and 28% o f women over the age o f 75 were unable to walk outdoors unassisted and 9% o f men and 19% o f women in the same age group were unable to use stairs or steps without help (Green, Milne, Rauta, Eldridge, W ilm ot and Levy, 1989). In a population based randomised controlled trial in Hackney, 16-25% o f over 85's living at home independently had significant difficulty getting on and o ff the toilet (Hart, B ow ling, Ellis and Silman, 1990). With respect to healthy elderly
men and women, it is necessary to develop tests which are safe to perform but will discriminate between people o f differing abilities. There are many assessment ’instruments' or questionnaires. They are not interchangeable and vary in their appropriateness for different purposes, different severities o f disability, different populations, and different cultures (Siu, Reuben and Hays, 1990). Only a few have been validated, and only in a few situations. Also, as with any form o f
questionnaire, subjects may overstate or understate their ability. There is enormous potential for their misuse.
TR AIN IN G IN OLD AGE:
Because o f the heavy demand on both the health service and the family o f a
dependent elderly person and the need to improve the quality o f life for that person there is an urgent need to find interventions to increase the number o f independent elderly people. When elderly people make the transition from independence to dependence, it is possible by early geriatric intervention and rehabilitation to slow the loss o f function and sometimes restore lost function. In this way, perhaps disability can be moved/kept to the smaller proportion o f elderly people with disability associated with chronic disease. In the enthusiasm surrounding
interventions to improve or maintain independence, w e must not forget the small proportion o f people who will be dependent or handicapped from disease to a degree where rehabilitation may not lead back to independent living. However, if this proportion can be kept to a minimum then services provided for their care will be better for not having to be spread over a larger number o f people.
There is evidence that exercise can improve strength in older adults (for review - (Buchner, Beresford, Larson, LaCroix and Wagner, 1992). There have been over 40 exercise training studies which have considered one or more measures o f strength as an outcome, in older subjects. Most have not been randomly controlled, have considered only the youngest 'old', or frail, institutionalised, elderly and not healthy elderly. Exercise classes have tended to be fully supervised, both adding to the cost and difficulty in arranging the classes and recruiting subjects. There is a need for information on adherence to and fitness improvements from less supervised classes (Buchner, Beresford, Larson, LaCroix and Wagner, 1992). Only two controlled training studies have considered muscular power, which is perhaps more closely related to functional ability than strength. One was a pilot study (Malbut et al. 1993) and in the other the subjects were only 51-57 years o f age (Bassey and Ramsdale, 1993). No study has considered muscle strength, power and functional ability in the same healthy group o f elderly people. The evidence that exercise improves
functional status is promising, but inconclusive (Buchner, Beresford, Larson, LaCroix and Wagner, 1992). If a loss o f function (or the crossing o f a threshold o f some activity) can be caused by a small loss o f strength or power, can a small
improvement in strength or power cause a person to re-cross the threshold for that activity, so that they are again able to perform it. Little is known about whether isolated improvements in strength or power can improve functional ability.
"Active life expectancy" was a concept developed by Katz et al. (Katz, Branch, Branson, Papsidero, Beck and Greer, 1983). He predicted that an average 65 year
old man has about 9 years o f active life and 4 years o f terminal dependence, a 65 year old woman has about 10 years o f active life and 9 years o f terminal dependence (Figure 2). So throughout old age, a woman's greater life expectancy is due almost entirely to her extra years o f terminal dependence or disability. Exercise may be an intervention that could improve the outlook for elderly people in terms o f reduced years o f dependence or disability.
Figure 2: Active life expectancy (a d apted from (Katz, Branch, Branson, Papsidero, B eck a n d Greer, 1983))
I
12
10
8
6
4
2
0
65-69
70-74
75-79
80-84
85+
Active Life Expectancy MEN
I Active Life Expectancy W OMEN
•Terminal Dependence MEN
-Terminal Dependence W O M EN
Age
THE PHYSIOLOGICAL BASIS OF FUNCTIONAL CAPACITY
Functional capacity is thought to decline at about 0.75 to 1% per year after the age o f 30 (reviewed by Schilke, 1991). Functional capacity is influenced by many different body systems - the circulatory system (cardiovascular and blood components), the musculoskeletal system (muscles, bony structures and body
composition) and the regulatory system (metabolic and nervous system). The loss o f ability to perform normal activities o f daily living does not depend solely on muscle strength or power. Maximal oxygen consumption (VOj max.) is a measure o f how efficiently the cardiovascular system transports oxygen to the tissues. VO2 max. has been shown, both in cross-sectional and longitudinal studies, to decrease at about
10% per decade. The ability to sustain muscular activity depends on ensuring the delivery o f an adequate supply o f oxygen to the working muscles and if s utilisation in their mitochondria. It depends, therefore, on both central cardiorespiratory function (a reduction in maximal heart rate, impaired myocardial contractility, an increased stiffness o f the larger blood vessels and an increase in blood pressure are seen with advancing age) and the capacity o f the peripheral muscles for aerobic metabolism (reduction in mitochondrial volume and oxidative enzyme activities are seen with advancing age) (Grimby and Saltin, 1983).
Oxygen delivery and oxidative energy release could deteriorate with age by a number o f means (reviewed by Bassey, 1986). Loss o f elasticity o f the tissues from greater cross-linkage between collagen molecules w ill give rise to stiffness in the joints and changes in elasticity o f lung alveoli leading to reduced vital capacity. A
