Stretching—An Important Strategy to Prevent Musculoskeletal Aging

10
246 www.topicsingeriatricrehabilitation.com October–December 2014 Topics in Geriatric Rehabilitation • Volume 30, Number 4, 246-255 • Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI: 10.1097/TGR.0000000000000032 This study aimed to review systematically the available evidence on the effects of stretching exercise on musculo- skeletal function of the elderly individuals. The search was performed in 4 databases. Twenty-four controlled clinical trials were included and the methodological qualities were measured using the JADAD scale. Stretching exercise improved gait speed ( P = .04), range of motion of hip uniarticular flexors ( P = .02), and ankle dorsiflexion ( P = .003) as compared with control groups. Stretching exercise can be considered as an intervention for elderly individuals in counteracting age-related decline in mobility. However, it is suggested new randomized clinical trials, focusing on the parameters to prescribe stretching exercise. Key words: aging, ankle, elderly, exercise, gait, joint range of motion, muscle stretching exercise Stretching—An Important Strategy to Prevent Musculoskeletal Aging A Systematic Review and Meta-analysis Talita Gianello Gnoato Zotz, MSc; Ana Paula Cunha Loureiro, MSc; Silvia Regina Valderramas, PhD; Anna Raquel Silveira Gomes, PhD Studies indicate that stretching exercises can improve yield of sports practices in young adults, 11-13 besides improving work-related musculoskeletal pain in adults, 14 increasing flexibility and torque in older community, 9 improving the muscle-tendon length and flexibility, and preventing torque loss in the institutionalized elderly indi- viduals. 10 However, the literature on the effects of stretch- ing exercises presents a lot of variation for its prescription and absence of a control group and randomized trials. 5-10 In this sense, a systematic review with meta-analysis of randomized clinical trials could provide more reliable esti- mates of the effectiveness of stretching exercises. There- fore, a meta-analysis of randomized clinical trials on the effects of muscle stretching exercises in institutionalized and community older adults was carried out. The objective of the study was to review the prescription parameters of muscle-stretching exercises and their effects on gait speed, ROM of hip extensors, uniarticular and biarticular hip flex- ors, dorsiflexors, and ROM peak of hip extension. METHODS Eligibility criteria Randomized and nonrandomized clinical trials that used a stretching protocol for elderly individuals were included in this study, as compared with no treatment, minimal intervention, and other types of intervention or other types of exercises, which assessed the following outcomes: gait speed, hip extension, hip biarticular flexors, hip uniar- ticular flexors, peak hip extension, and ankle dorsiflexion. Studies were published in scientific journals between 1963 and 2013 and without restriction on language of publica- tion. The exclusion criteria were as follows: (1) presence of many groups with different stretching protocols, (2) lack of prescription parameters for stretching protocol, (3) lack of control group, and (4) lack of data from the control group. Search strategy and selection of studies The search was performed and in duplicate, from 1963 to June 2013, through the electronic databases PubMed, Lilacs, Medline, and Cochrane Central Register of Con- trolled Trials (Cochrane CENTRAL). 15 The research was R educed flexibility is due to muscular adaptations leading to adaptive shortening of the muscle- tendon, which can affect mobility and equilibrium, thus modifying the functional impairments in the elderly individuals. 1-3 Changes in skeletal muscle resulting from the aging process occur both radially (in parallel) as decreased muscle mass and longitudinally (in series), by decreasing the fascicle length of the muscle and pennation angle. 4 Therefore, it has been shown that stretching exer- cises can improve muscle-tendon length, range of motion (ROM), torque, equilibrium, and the functionality in the elderly individuals. 5-10 Author Affiliations: Physical Education Department (Ms Zotz), Internal Medicine Postgraduate Program and Physiotherapy Department (Dr Valderramas), Physical Education Postgraduate Program and Physi- otherapy Department (Dr Gomes), Federal University of Paraná; Physio- therapy Department, Pontifical Catholic University of Paraná (Ms Loureiro), Curitiba, Paraná, Brazil. The authors declare that they have no conflicts of interest in the research. T.G.G.Z. is the recipient of CAPES/REUNI PhD fellowship. A.P.C.L. is the recipient of CAPES PhD fellowship (Process number BEX: 0590-13-4). A.R.S.G. is the recipient of productivity fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq (Process number 308696/2012-3). Correspondence: Talita Gianello Gnoato Zotz, MSc, Federal University of Parana, Odete Laura Foggiato St, Curitiba - PR, 82630-040, Brazil ([email protected]). Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. TGR-D-14-00024_LR 246 TGR-D-14-00024_LR 246 15/10/14 9:05 PM 15/10/14 9:05 PM

Transcript of Stretching—An Important Strategy to Prevent Musculoskeletal Aging

246 www.topicsingeriatricrehabilitation.com October–December 2014

Topics in Geriatric Rehabilitation • Volume 30 , Number 4 , 246 - 255 • Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins

DOI: 10.1097/TGR.0000000000000032

This study aimed to review systematically the available

evidence on the effects of stretching exercise on musculo-

skeletal function of the elderly individuals. The search was

performed in 4 databases. Twenty-four controlled clinical

trials were included and the methodological qualities were

measured using the JADAD scale. Stretching exercise

improved gait speed ( P = .04), range of motion of hip

uniarticular fl exors ( P = .02), and ankle dorsifl exion

( P = .003) as compared with control groups. Stretching

exercise can be considered as an intervention for elderly

individuals in counteracting age-related decline in mobility.

However, it is suggested new randomized clinical trials,

focusing on the parameters to prescribe stretching exercise.

Key words: aging , ankle , elderly , exercise , gait , joint range of

motion , muscle stretching exercise

Stretching—An Important Strategy to Prevent Musculoskeletal Aging A Systematic Review and Meta-analysis

Talita Gianello Gnoato Zotz , MSc ; Ana Paula Cunha Loureiro , MSc ; Silvia Regina Valderramas , PhD ;

Anna Raquel Silveira Gomes , PhD

Studies indicate that stretching exercises can improve yield of sports practices in young adults, 11-13 besides improving work-related musculoskeletal pain in adults, 14 increasing fl exibility and torque in older community, 9 improving the muscle-tendon length and fl exibility, and preventing torque loss in the institutionalized elderly indi-viduals. 10 However, the literature on the effects of stretch-ing exercises presents a lot of variation for its prescription and absence of a control group and randomized trials. 5-10

In this sense, a systematic review with meta-analysis of randomized clinical trials could provide more reliable esti-mates of the effectiveness of stretching exercises. There-fore, a meta-analysis of randomized clinical trials on the effects of muscle stretching exercises in institutionalized and community older adults was carried out. The objective of the study was to review the prescription parameters of muscle-stretching exercises and their effects on gait speed, ROM of hip extensors, uniarticular and biarticular hip fl ex-ors, dorsifl exors, and ROM peak of hip extension.

METHODS

Eligibility criteria Randomized and nonrandomized clinical trials that used a stretching protocol for elderly individuals were included in this study, as compared with no treatment, minimal intervention, and other types of intervention or other types of exercises, which assessed the following outcomes: gait speed, hip extension, hip biarticular fl exors, hip uniar-ticular fl exors, peak hip extension, and ankle dorsifl exion. Studies were published in scientifi c journals between 1963 and 2013 and without restriction on language of publica-tion. The exclusion criteria were as follows: (1) presence of many groups with different stretching protocols, (2) lack of prescription parameters for stretching protocol, (3) lack of control group, and (4) lack of data from the control group.

Search strategy and selection of studies The search was performed and in duplicate, from 1963 to June 2013, through the electronic databases PubMed, Lilacs, Medline, and Cochrane Central Register of Con-trolled Trials (Cochrane CENTRAL). 15 The research was

Reduced fl exibility is due to muscular adaptations leading to adaptive shortening of the muscle-tendon, which can affect mobility and equilibrium,

thus modifying the functional impairments in the elderly individuals. 1-3 Changes in skeletal muscle resulting from the aging process occur both radially (in parallel) as decreased muscle mass and longitudinally (in series), by decreasing the fascicle length of the muscle and pennation angle. 4 Therefore, it has been shown that stretching exer-cises can improve muscle-tendon length, range of motion (ROM), torque, equilibrium, and the functionality in the elderly individuals. 5-10

Author Affi liations: Physical Education Department (Ms Zotz), Internal

Medicine Postgraduate Program and Physiotherapy Department

(Dr Valderramas), Physical Education Postgraduate Program and Physi-

otherapy Department (Dr Gomes), Federal University of Paraná; Physio-

therapy Department, Pontifi cal Catholic University of Paraná (Ms Loureiro),

Curitiba, Paraná, Brazil.

The authors declare that they have no confl icts of interest in the research.

T.G.G.Z. is the recipient of CAPES/REUNI PhD fellowship. A.P.C.L. is the

recipient of CAPES PhD fellowship (Process number BEX: 0590-13-4).

A.R.S.G. is the recipient of productivity fellowship from Conselho Nacional

de Desenvolvimento Científi co e Tecnológico-CNPq (Process number

308696/2012-3).

Correspondence: Talita Gianello Gnoato Zotz, MSc, Federal University

of Parana, Odete Laura Foggiato St, Curitiba - PR, 82630-040, Brazil

( [email protected] ).

Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

TGR-D-14-00024_LR 246TGR-D-14-00024_LR 246 15/10/14 9:05 PM15/10/14 9:05 PM

Topics in Geriatric Rehabilitation www.topicsingeriatricrehabilitation.com 247

performed in June 2013 using the following terms: stretch-ing , elderly , aging , and muscle-stretching exercise. The terms were grouped with combination of the words used in the search for randomized and nonrandomized con-trolled trials. 16

Titles and abstracts of all articles identifi ed by the search strategy were evaluated independently by 2 investigators (T.G.G.Z. and A.P.C.L.), in duplicate. All abstracts that did not provide enough information on inclusion and exclu-sion criteria were selected to review the full text. In the sec-ond step, the same reviewers independently assessed the full-text articles to select those in accordance with the eligi-bility criteria. Differences between reviewers were resolved by consensus.

Data extraction Using standardized forms, the previous reviewers per-formed the data extraction independently, concerning the methodological characteristics of the studies, interven-tions and outcomes as well as differences, which were also resolved by consensus. The outcomes of interest were the following: gait speed, ROM, hip extension, ROM of hip biar-ticular fl exors, ROM of hip uniarticular fl exors, peak hip extension, and ROM of ankle dorsifl exion.

Risk of bias’ assessment and JADAD classifi cation The risk of bias’ assessment was performed by the same independent reviewers (T.G.G.Z. and A.P.C.L.) through the JADAD scale. 17 , 18 For each specifi c result, the evidence quality was based on 5 factors: (1) described as rand-omized, (2) described as double blind, (3) described losses, (4) appropriate randomization, and (5) appropriate mask-ing. The quality was reduced by 1 level for each factor not satisfi ed. The JADAD scale results in 2 levels of evidence and classifi es the study as poor quality (0-2) and high qual-ity (3-5). 18

Data analysis The selected articles were analyzed using the software Comprehensive Meta-analysis version 2.2 (Bio-stat Inc, Englewood, New Jersey).

Only continuous data were considered for analysis. The difference in means and their 95% confi dence intervals were calculated for individual trials, and the standardized mean difference was used as a summary effect size esti-mator. According to the Cohen 19 defi nitions, an effect size of 0.2 was considered small; 0.5, medium; and 0.8, large. The random-effects model was used to assess the mean difference measured in the meta-analysis. To assess the degree of heterogeneity, the I 2 test was also used, which describes the percentage of variation in the estimated effect. A value of more than 50% was indicative of substan-tial heterogeneity. 19

RESULTS

Description of the studies The search resulted in 6.265 possibly relevant titles from all databases, of which 42 studies were considered potentially relevant and selected for further analysis. Twenty-four of these studies involving 1.371 subjects met the eligibility cri-teria and were included in the systematic review. However, only 8 studies totalizing 365 elderly patients were included in the meta-analysis ( Table 1 ). Figure 1 shows the fl owchart of the selected studies.

Bias’ risk From the studies included in the systematic review (n = 42), 61.5% (n = 16) presented adequate randomization, 34.6% (n = 9) presented randomization, 26.9% (n = 7) reported blinding of researchers and patients, 19.2% (n = 5) presented a description of the blinding technique, and 65.3% (n = 18) showed losses in monitoring and exclusions ( Table 2 ).

Gait speed Four studies 7 , 26 , 30 , 31 evaluated the effects of a stretching pro-tocol on gait speed of older adults (n = 193). The analysis of those studies has shown that the stretching exercise resulted in a signifi cant improvement in gait speed when compared with the control group ( P = .04) ( Figure 2 ). According to JADAD classifi cation, 2 studies 30 , 31 from this meta-analysis showed high quality, while the other 2 7 , 26 showed poor quality ( Table 2 ). In addition, the studies included in the meta-analysis used different prescription parameters for stretching exercises; however, despite these differences, all studies have chosen to perform the super-vised static stretching exercise.

Stanziano et al 26 used a stretching protocol consisting of 10 repetitions, held for 5 seconds each time, totaling 50 seconds for each elongated muscle group (shoulder fl exors/abductors/extensors, hip extensors/abductors; lat-eral trunk fl exors; trunk rotators; trunk fl exors; ankle plan-tar fl exor muscles), with closed kinetic chain performed once a day, 2 times a week, for 8 weeks. The 50-foot-gait speed test was used to assess the outcomes.

Cristopoliski et al 7 reported a stretching protocol con-sisting of 4 repetitions of 60 seconds each time for the muscle groups of the hip extensors and dorsifl exors, total-ing 240 seconds for each muscle group, with closed kinetic chain, performed 3 times a week for 12 weeks. The method to assess the gait parameters was videotaped using 4 digital camcorders (JVC, GR-D250).

Watt et al 30 presented the following stretching protocol: 1 set of 4 repetitions of 60 seconds each time, with an inter-val of 60 seconds between each repetition; closed kinetic chain for the single joint hip fl exor muscles, performed

Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

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248 www.topicsingeriatricrehabilitation.com October–December 2014

TAB

LE 1

Chara

cte

rist

ics

of

the S

tudie

s Fro

m t

he P

rese

nt

Revi

ew

Refe

rences

Stu

dy

Desi

gn

Part

icip

ants

Inte

rvention N

um

ber

of

Part

icip

ants

=

Contr

ol N

um

ber

of

Part

icip

ants

=

Variable

s

Zakas

et al 2

0

Not in

form

ed

22 s

edenta

ry h

ealth

old

wom

en

(Pro

tocol 1)

(Pro

tocol

2)

(Pro

tocol 3)

22

part

icip

ants

fro

m

each g

roup

22

RO

M-g

onio

mete

r: T

runk fl e

xion, fl exi

on o

f th

e h

ip join

t,

ext

ensi

on o

f th

e h

ip join

t, a

bduction o

f th

e h

ip join

t,

knee fl e

xion a

nd a

nkle

dors

ifl e

xion

Gallo

n e

t al 1

0

Not in

form

ed

17 inst

itutionaliz

ed

eld

erly

wom

en

89

Left U

L, B

I, L

ysholm

Scoring S

cale

, is

okin

etic

eva

luation, photo

gra

mm

etr

y

Johnso

n e

t al 2

1

Not in

form

ed

20 h

ealth w

om

en

20

0R

OM

of ankle

fl e

xion

Ferb

er

et al 2

2

Not in

form

ed

26 h

ealthy

old

adults

26

0Ele

ctr

ogonio

mete

r, s

urf

ace E

MG

Kerr

igan e

t al 2

3

Double

-blin

ded,

random

ized,

contr

olle

d trial

96 h

ealthy

eld

erly

indiv

iduals

47

49

RO

M o

f hip

ext

ensi

on, hip

join

t m

ove

ment and L

L

bila

tera

lly d

uring g

ait, gait v

elo

city,

kin

etic a

nd

kin

em

atic g

ait, sp

eed, cadence, st

ep length

, hip

ext

ensi

on torq

ue, R

OM

in p

lanta

r fl exi

on,

pla

nta

rfl e

xion forc

e, ante

vers

ion p

elv

ic

Lust

osa

et al 2

4

Quasi

-exp

erim

enta

l st

udy

25 c

om

munity-

dw

elli

ng

eld

erly

wom

en

13

12

Isokin

etic d

ynam

om

etr

y

Rodacki et al 2

5

Not in

form

ed

15 c

om

munity-

dw

elli

ng

eld

erly

wom

en

15

0K

inem

atics

gait a

naly

sis

Sta

nzi

ano

et al 2

6

Not in

form

ed

17 e

lderly

resi

dents

of a r

esi

dential

retire

ment

com

munity

89

Fle

xibili

ty test

: th

e b

ack-s

cra

tch test

(B

S),

RO

M,

functional perf

orm

ance; knee e

xtensi

on in s

upin

e

test

, to

tal body

rota

tion test

. Str

ength

and p

ow

er

of

LL, U

L s

trength

, core

pow

er

Sw

ank e

t al 2

7

Not in

form

ed

43 h

ealthy

eld

erly

indiv

iduals

32

11

RO

M

Batist

a e

t al 9

Not in

form

ed

12 a

ctive

old

er

wom

en

12

0R

OM

, is

okin

etic torq

ue o

f knee fl e

xors

and e

xtenso

rs

and functional perf

orm

ance

Christ

ianse

n

et al 2

8

Random

ized

contr

olle

d trial.

40 h

ealthy

eld

erly

indiv

iduals

20

20

RO

M; kin

em

atics

analy

sis

of gait, st

ep length

, dis

pla

cem

ent of th

e s

egm

ent.

Crist

opolis

ki

et al 7

Not in

form

ed

20 h

ealthy

old

er

wom

en

12

8Thre

e-d

imensi

onal gait a

naly

sis,

photo

gra

mm

etr

y,

length

of m

usc

le-t

endon r

ectu

s fe

moris

and

pso

as

ilium

Fela

nd e

t al 5

Not in

form

ed

62 indiv

iduals

fro

m a

re

tire

ment house

49

13

RO

M

Gajd

osi

k e

t al 6

Not in

form

ed

19 e

lderly

wom

en

10

9G

ait s

peed, bala

nce, grip s

trength

, EM

G

Gurjão e

t al 2

9

Not in

form

ed

23 e

lderly

wom

en

23

0M

usc

le s

trength

(is

okin

etic)

test

, EM

G

(continues)

Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

TGR-D-14-00024_LR 248TGR-D-14-00024_LR 248 15/10/14 9:05 PM15/10/14 9:05 PM

Topics in Geriatric Rehabilitation www.topicsingeriatricrehabilitation.com 249

TAB

LE 1

Chara

cte

rist

ics

of

the S

tudie

s Fro

m t

he P

rese

nt

Revi

ew

(Continued )

Refe

rences

Stu

dy

Desi

gn

Part

icip

ants

Inte

rvention N

um

ber

of

Part

icip

ants

=

Contr

ol N

um

ber

of

Part

icip

ants

=

Variable

s

Watt e

t al 3

0

A d

ouble

-blin

ded,

random

ized, con-

trolle

d trial

82 h

ealthy

eld

erly

indiv

iduals

43

39

RO

M e

xtensi

on o

f th

e h

ip join

t, length

of m

usc

le-

tendon r

ectu

s fe

moris

and p

soas

ilium

, dyn

am

ic

peak h

ip e

xtensi

on, peak o

f pelv

ic a

nte

vers

ion,

stride length

, gait s

peed (

3D

gait a

naly

sis)

Watt e

t al 3

1

A d

ouble

-blin

ded,

random

ized, con-

trolle

d trial

74 fra

il eld

erly

indiv

iduals

33

41

Dyn

am

ic p

eak h

ip e

xtensi

on, peak p

elv

ic a

nte

vers

ion,

stride length

, gait s

peed in c

om

fort

able

and fast

st

ep, jo

int ext

ensi

on R

OM

in the h

ip

Burk

e e

t al 3

2

Random

ized c

on-

trolle

d trial

50 w

om

en a

ged 6

5

years

or

old

er

17 (

pro

tocol 1)

17 (

pro

tocol 2)

16

Post

ura

l contr

ol, m

usc

le s

trength

with d

ynam

om

ete

r w

ith R

OM

of LL

Lam

et al 3

3

Sin

gle

-blin

d c

lust

er

random

ized c

on-

trolle

d trial

389 s

ubje

cts

at risk

of

cognitiv

e d

eclin

e171 (

Tai chi)

218 (

stre

tchin

g a

nd

to

nin

g e

xerc

ise)

Pro

gre

ssio

n o

f dem

entia, cognitiv

e s

core

, depre

ssio

n,

dyn

am

ic e

quili

brium

Gallo

et al 3

4

Not in

form

ed

57 e

lderly

wom

en fro

m

com

munity

15 (

pro

tocol 1)

14 (

pro

tocol 2)

14

Functional capacity

(fl e

xibili

ty, coord

ination, agili

ty a

nd

dyn

am

ic b

ala

nce, re

sist

ance o

f m

usc

ula

r st

rength

and a

ero

bic

resi

stance, genera

l fu

nctional In

dex

Pom

perm

aye

r and

Gonçalv

es 3

5

Desc

riptive

ex-

post

-fa

cto

23 h

ealthy

eld

erly

wom

en b

etw

een

60-

and 8

0-y

ear

old

2 g

roups—

num

ber

not

desc

ribed p

er

gro

up

LL F

orc

e, U

L P

ow

er, L

L F

lexi

bili

ty, U

L F

lexi

bili

ty, A

gili

ty/

Equili

brium

, A

ero

bic

s R

esi

stance

Gom

es

et al 3

6

Exp

erim

enta

l analy

ti-

cal

83 e

lderly

indiv

iduals

12 (

pro

tocol 1)

21 (

pro

tocol 2)

15 (

pro

tocol 3)

35

Sys

tem

ic B

P, B

MI, D

ynam

ic B

ala

nce, G

ait Index

(dyn

am

ic g

ait),

musc

le s

trength

Vare

jão e

t al 3

7

Not in

form

ed

69 e

lderly

indiv

iduals

36 (

pro

tocol 1)

33 (

pro

tocol 2)

RO

M (

cerv

ical sp

ine r

ota

tion, horizo

nta

l fl exi

on o

f th

e

should

er, h

orizo

nta

l ext

ensi

on o

f th

e s

hould

er

join

t,

fl exi

on o

f th

e s

hould

er

join

t, fl e

xion o

f th

e lum

bar

spin

e, fl exi

on o

f th

e h

ip join

t, fl e

xion o

f th

e k

nee),

Functional A

ssess

ment of daily

liv

ing a

ctivi

ties

(gait s

peed, equili

brium

, fu

nctional perf

orm

ance)

quest

ionnaire W

HO

QL-1

00.

Halle

gra

eff

et al 3

8

A r

andom

ized trial

with c

onceale

d a

l-lo

cation a

nd

inte

ntion-t

o-t

reat

analy

sis

N =

80 e

lderly

indiv

id-

uals

with n

octu

rnal

pain

s in

the L

L, and

cra

mps

N =

40 P

resl

eep

stre

tchin

g; M

ain

tain

usu

al activi

ties

N =

40

BM

I, D

aily

phys

ical activi

ty (

pedom

ete

r), Str

ength

and

LL F

unctionalit

y, n

ight cra

mps,

seve

rity

of cra

mps

(VA

S)

Abbre

viations:

BI, B

art

hel in

dex;

BM

I, b

ody

mass

index;

BP, blo

od p

ress

ure

; EM

G, ele

ctr

om

yogra

phy;

LL, lo

wer

limb; R

OM

, ra

nge o

f m

otion; U

L, upper

limb; VA

S, vi

sual analo

g s

cale

; W

HO

QL, W

orld H

ealth O

rganiz

ation

qualit

y of lif

e a

ssess

ment in

stru

ment.

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daily, for 10 weeks. The gait assessment’s method used was a VICON system. In another study, these authors 31 used the same stretching protocol for the same muscle group and outcome method; however, the study was performed with frail elderly individuals in the community.

RANGE OF MOTION

ROM of hip extension Two studies 7 , 23 evaluated the ROM of hip extension (n = 116). It can be observed that the stretching exercise did not favor intervention groups ( P = 0.26) ( Figure 3 ). According to the JADAD classifi cation, one study showed high qual-ity 23 while other presented poor quality. 7 In the study reported by Kerrigan et al, 23 the exercise prescription was characterized by the absence of supervision, that is, the individuals were trained by a professional and made the stretching protocol at home without supervision. The active static stretching protocol prescribed in this study was 1 set of 4 repetitions of 30 seconds each time at inter-vals of 30 seconds between each repetition; closed kinetic

chain, held twice a week for 8 weeks for uniarticular fl exor hip. ROM of hip fl exion was measured with a goniometer. Cristopoliski et al 7 used the supervised passive static stretching for the hip fl exor muscles with 1 set of 4 repeti-tions of 60 seconds each time, and 60-second interval between each repetition; closed kinetic chain 3 times a week for 4 weeks.

ROM of hip biarticular fl exors and ROM of hip uniarticular fl exors All articles 7 , 10 of this meta-analysis evaluated the ROM of hip biarticular fl exors (n = 37), and no statistical signifi cance was observed ( P = 0.14) ( Figure 4 ). However, a statistical signifi cance was found for the ROM of hip biarticular fl exors in the stretching group ( P = .02) ( Figure 5 ). Both studies were classifi ed as poor quality according to the JADAD quality rating scale.

Gallon et al 10 evaluated the effect of the supervised active static stretching on the ROM of hip fl exors using the follow-ing stretching protocol: 1 set of 4 repetitions of 60 seconds each time, with a 60-second interval between each repetition;

Figure 1. Steps performed in the selection process and reasons for exclusion .

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Figure 2. Forest plot (meta-analysis, random-effects model) of standard difference in means and 95% confi dence intervals, for 4 studies demonstrating the difference between the control and stretching groups.

TABLE 2 Bias’ Risk for the Included Studies and JADAD Classifi cation

References Randomization

Description of Randomization

Method Blinding

Description of Blinding

MethodDescription of Losses

JADAD Classifi cation

Zakas et al 20 Yes No No No Yes Poor quality

Gallon et al 10 Yes No No No Yes Poor quality

Johnson et al 21 No No No No Yes Poor quality

Ferber et al 22 No No No No No Poor quality

Kerrigan et al 23 Yes Yes Yes Yes Yes High quality

Lustosa et al 24 Yes No No No Yes Poor quality

Rodacki et al 25 No No No No No Poor quality

Stanziano et al 26 Yes No No No No Poor quality

Swank et al 27 No No No No Yes Poor quality

Batista et al 9 No No No No Yes Poor quality

Christiansen et al 28 Yes Yes Yes Yes Yes High quality

Cristopoliski et al 7 Yes No No No Yes Poor quality

Feland et al 5 Yes Yes No No Yes High quality

Gajdosik et al 6 Yes Yes No No Yes High quality

Gurjão et al 29 No No Yes No Yes Poor quality

Watt et al 30 Yes Yes Yes Yes Yes High quality

Watt et al 31 Yes Yes Yes Yes Yes High quality

Burke et al 32 Yes Yes No No Yes High quality

Lam et al 33 Yes Yes Yes Yes Yes High quality

Gallo et al 34 No No No No No Poor quality

Pompermayer and Gonçalvez 35 No No No No No Poor quality

Gomes et al 36 Yes No No No Yes Poor quality

Varejão et al 37 No No No No No Poor quality

Hallegraeff et al 38 Yes Yes Yes No Yes High quality

closed kinetic chain, 3 times per week for 8 weeks. Before the stretching exercises, ludic activities were performed for 10 minutes to warm up. The outcomes muscle-tendon length of uni- and biarticular hip fl exors and hamstring fl ex-ibility were assessed by a photogrammetric method.

Cristopoliski et al 7 used the supervised passive static stretching for the hip fl exors, with a set of 4 repetitions of 60 seconds each time, and 60-second interval between each repetition; closed kinetic chain 3 times a week for 4 weeks. Thus, it appears that the stretching technique

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was similar for all studies, differing only as to the execution mode, active or passive.

Although the prescription parameters of the stretch-ing protocol were the same for both studies, the study of Gallon et al 10 lasted for more than 4 weeks after the study of Cristopoliski et al. 7

ROM peak of hip extension All the articles 30 , 31 of this meta-analysis evaluated the ROM peak of hip extension (n = 156), and no statistical signifi -cance was observed between them ( P = 0.36). The studies showed high quality according to JADAD classifi cation. The limitation parameters of these studies have been cited earlier in the Gait speed outcome. It is noteworthy that the exercises from both studies were supervised for static active stretching ( Figure 6 ).

ROM of ankle dorsifl exion The articles selected 6 , 28 for the meta-analysis evaluated the ROM of dorsifl exion (n = 59) and presented statistical sig-nifi cance for the stretching group ( P = .003) ( Figure 7 ). Christiansen et al 28 observed the effect of the unsuper-vised active static stretching on the ROM of dorsifl exors using the following prescription parameters: a set of 3 rep-etitions of 45 seconds each time, at intervals of 45 seconds between each repetition; closed kinetic chain, performed 2 times a day, every day for 8 weeks. The muscle groups elongated in that study were plantar fl exors and uniarticu-lar hip fl exors. In contrast, Gajdosik et al 6 used a stretching apparatus in which only the right heel could be elongated,

using a set of 10 repetitions of 15 seconds each time. The exercises were supervised static passive stretching, in closed kinetic chain 3 times a week for 8 weeks, and the interval between the repetitions was not reported by the authors.

DISCUSSION In this systematic review, it was found that the stretching exercise was associated with signifi cant improvement in ROM of the uniarticular hip fl exors and dorsifl exors and gait speed in elderly individuals. However, the increase in these outcomes was induced when the muscle-stretching protocol was performed for at least 4 weeks. It is notewor-thy that all studies in the meta-analysis were carried out in closed kinetic chain.

The closed kinetic chain induces co-contraction of the agonist and antagonist muscle groups. 39 Thus, when stretching exercise is performed in closed kinetic chain, it can change the passive elastic components contributing to increase the skeletal muscle-tendon length and joint ROM. 22 , 40

It has been reported that the decrease in musculoten-dinous stiffness induced by the acute effect of a single stretching session may return to baseline within 20 min-utes. 41 Therefore, with respect to the regularity of the stretching exercises, American College of Sports Medicine (ACSM) has recommended between 2 and 3 times per week for increasing fl exibility, while 5 and 1 time per week is recommended for more signifi cant gains and muscle maintenance, respectively. 42

Figure 3. Forest plot (meta-analysis, random-effects model) of standard difference in means and 95% confi dence intervals, for 2 studies demonstrating the difference between the control and stretching groups.

Figure 4. Forest plot (meta-analysis, random-effects model) of standard difference in means and 95% confi dence intervals, for 2 studies demonstrating the difference between the control and stretching groups.

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Statistically signifi cant difference was observed in this meta-analysis with regard to the increased ROM of dorsi-fl exion, due to the regular practice of stretching exercises for 8 weeks in elderly individuals. 6 , 28 Gajdosik et al 6 pre-scribed passive stretching, performed using an isokinetic dynamometer (5 per second) 1 time a day, with a set of 10 repetitions for 15 second each, performed 3 times per week. In the study of Christiansen, 28 the static stretching protocol in closed kinetic chain consisted of 3 repetitions of 45 seconds each, 2 times a day, every day.

The increase in dorsifl exion ROM observed by Gajdosik et al 6 and Christiansen 28 has confi rmed the rec-ommended frequency by ACSM between 2 and 3 times a week. 42 With respect to the number of times the stretch-ing protocol should be done in a day, the effect of stretch-ing exercises on 1 or 3 times per day in young adults has been reported, and no statistically signifi cant difference was detected when the daily frequency was increased. 43 Therefore, further studies are necessary to investigate the effects of stretching protocols performed in different daily frequencies to elucidate this prescription parameter.

The ACSM 42 recommends that physical exercise is nec-essary to improve and maintain health of the elderly pop-ulation, with activities that include aerobic exercises, and strength, fl exibility, and equilibrium training. Evidences for prescribing muscle stretching exercises recommended to gain fl exibility, have 3 to 4 repetitions, with duration between 30 and 60 seconds of each repetition.

In the case of elderly people, an important issue that should be noted is the functional performance, particu-larly gait, 28 which declines with age, increasing the risk of falls. 44

This meta-analysis shows an improvement in gait as a favorable outcome to the stretching protocols. 7 , 26 , 30 , 31 Stanziano et al 26 prescribed a stretching protocol consist-ing of 10 repetitions, lasting 4 to 5 seconds each, and held in 10 different muscle groups, twice a week for 8 weeks. These authors observed an increase in not only ROM but also in the mobility and functionality of elderly living in a residential retirement community. Cristopoliski et al 7 also found an improvement in gait parameters in elderly community after prescription of unsupervised stretching

Figure 5. Forest plot (meta-analysis, random-effects model) of standard difference in means and 95% confi dence intervals, for 2 studies demonstrating the difference between the control and stretching groups.

Figure 6. Forest plot (meta-analysis, random-effects model) of standard difference in means and 95% confi dence intervals, for 2 studies demonstrating the difference between the control and stretching groups.

Figure 7. Forest plot (meta-analysis, random-effects model) of standard difference in means and 95% confi dence intervals, for 2 studies demonstrating the difference between the control and stretching groups.

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protocol consisting of 3 repetitions with 45-second dura-tion each, twice a day for 8 weeks. Thus, we suggest studies to verify the duration of the effect of stretching program on gait when acute and chronic protocols are performed as well as the detraining effects.

Costa et al 45 reported the effects of stretching exercises on the major muscle groups of the lower limbs, performed 2 times a week for 12 weeks, and analyzed the detraining effects. The stretching increased hip fl exion and main-tained it after detraining. However, when stretching was associated to resistive training, it increased hip extension after 6 and 12 weeks and maintained after detraining. The authors concluded that although resistive exercise or stretching, performed alone, was suffi cient to increase ROM, the stretching exercise was determinant in an early gain and its maintenance.

The improved gait can be due to the changes in the movement of the pelvis during gait induced by the muscle-stretching exercise in the hip and ankle region 7 together with the increase of ROM of both uniarticular hip 7 , 10 and ankle dorsifl exors. 6 , 28

Batista et al 9 found that muscle stretching performed in an elderly community, using a protocol of 7 repeti-tions 1 minute each, twice a week for 4 weeks increased 45% ROM of knee fl exors and improved functional mobil-ity in older women. Likewise, Christiansen 28 found that muscle stretching also held twice a week in elderly com-munity with 3 repetitions of 45 seconds each, for 8 weeks increased by 11% ROM of dorsifl exion, besides an increase in gait speed. Comparing the outcomes of these studies, it is found that when the stretching exercise carried out for just 4 weeks only 2 times a week was enough to increase ROM and functionality.

According to Soucie et al, 46 aging reduces ROM of joints, and both ROM of hip extension and dorsifl exion suffer a reduction of 7.7% and 15.9%, respectively, which under-mines the proper execution of the gait walk analysis. Thus, as explained by the meta-analysis of this systematic review, the muscle stretching performed in elderly individuals statically supervised at least 2 times a week demonstrated positive effects on gains of ROM of uniarticular hip fl exors and dorsifl exors from 4 weeks protocol.

It is found that the prescription parameters of stretch-ing exercises for elderly people and the evaluation of their effects are not standardized. Thus, further studies are needed, using similar prescription parameters and evalua-tion of outcomes for comparison purposes.

Strengths and limitations of the review A systematic review with meta-analysis was performed, because this type of study can provide more reliable esti-mates of treatment effectiveness than individual tests due to its greater statistical power. 47 However, differences in prescription parameters of stretching exercises used in the

studies, as well as the methods for analyzing the outcomes, have limited the results.

In the systematic review, many studies were method-ologically limited by the degree of bias. Only 5 studies clearly described the blinding technique (patients and therapists). 23,28,30,31,33 In addition, only 9 studies 5 , 6 , 23 , 28 , 30-33 , 38 described the randomization method, which has limited the systematic review with meta-analysis.

CONCLUSIONS This systematic review with meta-analysis suggests that mus-cle-stretching exercise for older people improves both gait speed and ROM of the hip fl exors and dorsifl exors, which can be considered as an intervention for the elderly indi-viduals. However, the methodological quality of the arti-cles suggests that further randomized controlled trials are needed on this subject, with special focus on the prescrip-tion parameters of stretching exercises. Studies should be planned with greater methodological rigor, higher number of individuals, and better-detailed prescription parameters.

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