東京大学教養学部体青学紀要 (1992)26, 49〜 58

Mechanical Power Developed during Simulated

Pull Movements in Weightlifting

Kazuo Funato, Akifumi Matsuo and Tetsuo Fukunaga
Dept. of Sports Sciences, College of Arts and Sciences,

University of Tokyo

Abstracl

Mechanical power outputs were measured during simulated pull movements in$,eightlifting to see how the mechanical power relates to the athletic
performance, For this purpose, a dynamometer was nerrly developed for measuringforce, velocity, work and power. The loads against the morrements were provided
by adding plates of various weights to the inertia wheel. Subjects pulled thewire which was wound around the axis of the inertia wheel. Mean velocity (MV),mean force(lvt F ) and mean power (MP) were determined by dividing integrals of

the instantaneous velocity, force and power curves, respectively, with time.
Pull movement in weightlifting from the starting position (first pull) to thefinal pull (S I ) was divided into three components i. e., leg extension (S -! ), hip extension (g ! ) and shoulder shrug ($ 4 ). Subjects were twentytwo Japanese weightlifters including eight elite and fourteen district level
lifters. Mean values of MPs under the load of 15kgw were 1024.4, 999.9, 561.8
and 299.3n,, respectively, when measured separately in the movement condition of
S I, S-2, S-3 aDd S- 4. In each movement condition, MF-MV and
M V - M P relations were obtained from measurements with different loads. M
V decreased in a hyperbolic manner and M P showed a peak with increasing M F
In elite level lifters, both MV and MP were higher than those in districtlevel lifters at an identical MF level. St&tistically significant positive
linear correlation (r=0.838, p<0.001) was observed between Mp exerted during
the S I movement and the athletic performance expressed as the total weight(snatch+ clean&jerk) recorded in competition. It is concluded that themechanical power measured during the simulated pull movement in weightlifting

Funato, Matsuo , Fukunaga

with the present dynamometer is useful for evaluating, and therefore improving
the athletic performance. Furthermore, this dynamometer is capable of providing
the force-velocity characteristics during multi-articular movements of various
body segments.

Key words : New dynamometer, mechanical power, simulated pull movement,
weightlifting

Mechanical Power Developed during Simulated Pull Movement in Weightlifting

lnt roduct ion

In humn natural fiovelents inc].uding thosein sports, tension generated by [uscle
contraction is transferred to the external
objects via bones and joint systens. Forceyorking onto the external object varies both
physically and physiologically according to
the muscle lenght, the contraction speed
and the mode of contraction etc.
For evaluating muscle strength, the use of
dynamomerer has ridely adopted, in whichcounter force of muscle contraction can bel[easured by control I ing mechanicalresistance in various rays' I rB ''g '3'. (i.
e,, static, isotonic and isokinetic loading
systeus). In studies trith these methods,
the najor interest has so far been focusedon the [echanical characteristics of thenuscle itself" t1' 22.21 23), since in thesestudies, the extermal force ras [easured
under restricted condition in terns of the
posture, the range and the velocity ofjoint motions.
Performance in the athletic sport Dight
not be fulLy related to the nechanicalcharacteri st i cs of individual muscle
determined by the [ethods xentioned above.

Indeed, rany factors affecting the Length-

tension, the force-velocity relations andthe contraction [odes of the Iuscles
involved in the real movenent right be sovariable rith tine and from nuscle to [uscle
that they can not be predicted fron thoseobtained under specific loading conditions.
0n the other hand, the vertical jump test'' ' ' ") has been videly accepted as themethod to evaluate force, velocity, f,ork
and porer during short explosive rhole-bodylovell|ent. Iloyever, it is thought thatnechanical variables deternined trith thevertical jump tests do not necessarily
represent the [axnun pof,er of the subject,since the load on each nuscle during thelift rork against gravity is restricted by
the subject's body mss.

In thi s s tudy, re developed a ner
dynarotreter for Deasuring force, velocity,

york, and porer under inertia loading
condition during nulti-joint, explosiveroverents. Iith this equiplent, 0echanicalporer outputs during pu11 [ovement inreightlifting rere measured to evaluate theflechanical pof,er related to the athletic
perfornance, particularly aiming the futureapplication of the dynamoneter to inprove
the athletic perfornance in reightlifting.
Iothods
Apparatus

A dynanometer "Pover Processor" (Vain Co.

Ltd., Tokyo, Japan) for the [easurenent offorce, velocity, rork, and porer ras ne*ly
developed (Fig. 1). techanical parts of the"Porer Processor" consist of a rotary
encoder, an electrical rinder, a Eagnetic
brake syste[, a load cell, and an inertia
loading systell]. Time required for l/100
rotation of the inertia yheel ras measured
by rotary encoder. Tension on the rire tras
oeasured by the load cel1. The [agnetic
brake syste[ and electric ootor act as the
stoppers of the rotation of inertia rheel
and that of the rinder of rire around theaxis of inertia *heel, respectively. Loadras given by adding plates of knorn Yeights
to the inertia rheel, rhich rere ranged
from 0 to 25kgr, i.e.,50.70 to 3ll.98kg ofequivalent nass, respectively.
As shorn in the bLock diagran of Fig. L
electrlcal signals from the rotary encoder
and the load cell rere sa[pled at every

five milliseconds and stored in the I C
Iemory card, then read by a personal
computer (PC980tVM, NEC Co., Tokyo,
Japan) through an interface and used forfurther analyses.

Funato, Matsuo, FukunagaJ

7.

Fig. I Nerly developed dynarcmeter "Porer Processor" (left) and its structure andblock diagratr for mechanical neasureuents (right).
Procedures

Subjects pulled the rire rhich ras roundaround the axis of the inertia rheel via apulley systetr, as shom in Fig.2. Four kindsof sioulated pul1 movenent in reightlifting
rere perforued : S- 1, the pull fron thestarting squat position to the final pull
position in reightlifting ; the other three,
the pull move0ents performed only by leg
extension(S - 2 ), hip extension (S 3 ),and shoulder shrug(S 4 ), respectively(Fig. 4).

I

Fig. 2 Pull movenent in reightlifting corpetition (right) and oeasurerent offlechanical poYer during sillulated pul1 movement in reightlifting using Porer
Processor (1eft).

Mechanical Power Developed during Simulated Pull Movement in Weightlifting

Xechanical neasurements

Velocity of the fllre along its axis ras
calculated frofl the angular velocity of theinertia rheel recorded by rotary encoder. An
instantaneous pof,er curve flas calculated bynlul t ipiyi ng instantaneous velocity andforce. As shom in Fig.3,

53

rork (W) ras deterfiined by integrating
porer rith respect to time, rhile nean force(MF), nean velocity (MV) and rean pover(M P ), rere deterrined by dividing
integrals of force, velocity and pof,er,
respectively, by tine.
Force Vel ocl ly

Pover( ) (a/sec)
35BB 14

(II)

1750

D :585ms
u :520 7J
MF:606 5Nw=

r,,
Jh P(t)dt

MF=LtQ,- h)

V:1 69■ /s

I" Flt)dt

Mv_r^t,_ h)1,'vu)dt

MP:890 11
PP:1660 8リ

MP=rtG-h)I" P(t)dt

a

tl

1000

Tire (ns)Fig.3 Typical recordings of instantaneous velocity, force and pof,er curves
during siflulated pull moverent in reightlifting (S I ) D:duration, f:vork,tF:llean force, tV:[ean velocity, f,P:mean po*er, PP:peak potrer

Fig.4 shors i ns tan taneous velocity,

Subjects

Subj ects f,ere tyen ty-tflo Japaneseforce,and porer curves obtained fron four

treightlifters including eight elite lifters(Seou1 0lynpic lifters, body veight nean t
SD : 69.0 +l5.zkc) and fourteen district
lifters (six junior and eight senior lifters,
body yeight mean tSD : 69.5 t l0.2kg).
Athletic perfornance expressed as the total
best weieht Iifted (snatch+c1ean & jeak)
per body f,eight rere 4.23 ) 0.29ke/BW(meantSD) for elite lifters and 3.231
0.56kg/BW (meanlSD) for district lifters.

simulated pull movenents. Tro peaks appearedin the in force and pover curves during the
Doverent of yeightlifting pu11(S - I ) and

Results

ilean values of maxinu[ MPs exerted infour sets of simulated movement by all

subjects rere 1024.4, 999. 9, 561. 8 and299.3Y for S-1, S-2, S-3 and S-

4, respectively.

the leg extension(S - 2), which may reflect
the double knee bending [ovenent as used in
the fleightlifting technique.
Fig.s shovs changes in MP rith load foreach movelent condition. Iaxifiun MPs flere
exerted under the loads betyeen 5kg{ andl5kgr in all moveBent conditions. Iligher
values ofM P f,ere observed in S - 1
movenent than in

S-2, S-3, and S-4,

condition. Higher values of absolute MP
values yere observed in elite lifters thanin district .tifters. In S - I novement,tean(S D) values of MPs relative td bodyfleight under the load of 101(g flere 15.6

54

Funato. Matsuo. Fukunaga・ ̀￨li:liill

ト

(・

↑
S‑1

neasure[ents [ith five different inertia
loads as shorn in Fig.6. f,ith increasing M

F, MV decreased in an apparentlyＤhyperbolic nanner and MP seemed to shou apeak. In elite lifters, both MV and MP
rere higher than those in district lifters
at an identical MF level.
Fig.7 shors the relationship betf,een MP︱

and athletic performance in reightlifting.
The athletic performance rere assessed as

the total fleights lifted by snatch and clean→& jerk in the same competition.
Stati st ical ly significant positive linear

S‑2‐correlation ras observed betreen M P sのdeveloped in all simulated pull novements
and the athletic perfornance. Horever, thecorrelation f,as s t ronge r in S - I
loveInent than in other three [ovenent
conditions.

↑S‑3

D iscuss ion

４

Iany kinds of ergo[etry have bee ndeveloped for measuring the physiologicalcapability of hu[ans during high intensity
and short duration exercises. Stairclimbing'' '0) and Iingate test3''') havebeen ridely accepted for evaluating the→４Ｓhuman anaerobic capacity during repetitive・,,- ,ilfig.4 Four sirulated pu11 [overent conditions rhich are involved in the f,eightlifting rovenent and typical recordingsof instantaneous velocity, force and po$er.
(1.6) I/kg B.W. for elite ]ifters and 10.
0 (1.7) t/kg B.W. for district lifters.
MPs developed during S-2, S-3, and- 4 movements corresponded to 94N, ?ZX,
and 43rd of M P developed during S - I
Slnovelllent, respectively,

In each 0ovement condition, MF -MV andM F M P relations *ere obtained fror

[uscle contraction. Pof,er measured rithsuch rethods horever, night be different
from that exerted by an explosive llovement
performed by a strong muscle contraction
lasting for ]ess than a second, Furthermore,in protocols taken by the above [ethods,
essential parameters for calculating porersuch as force and velocity are not direc y
Ieasured,Special equipments f,ith an isometric or
i sokinet ic loading systen'(e. g., Cybex dynamometer) have so far beenf,ide1y used for evaluating either muscle
strength or power developed during single
muscle contraction Lasting for less than aMechanical Power Developed during Simulated Pull Movemerit in Weightlifting〔S‐ 31ISl】

ＮＪ︵ 夕 ｍＯどヽ夕 ︶ Ｌ●３ ０﹂ ｃＯ●Σl?

0

0 5 10 15 20 25

5 10 15 20 25〔S

ｒｒｒｌ⁚︱トトトーーＬｌＬＬ

15‐ 21

〕

￨￨￨￨￨

0

5 10 15 20 25

0

5 10 15 20 25

Weights of plates(kg)Fig 5 Changes in mean power(MP, watts/kgB W) With load for each movement
condition.

︒口 ・
″
．

０ ．

︒
ｏ 鴫

θ

口

S ubi::S。 ('u niOr)

ヽ

一
一 ．

︒

Meon Force (N)Ｌ ︒● Σ

ヨ

︒﹂甲

．
・ ． ヽ

０

ｃＯ一

. s-l

250 500 75010001250

ヽ嘔

︒

０

︐

ｏ２ ●

︵゛ヽ ε ︶ ︑ 一６ ｏ 一０＞Ю︵●ヽＥ ︶ ︑

oS‐ 2

oS‐ 3

0

︑

︐

ｃｏ ● 三

０

７¨´ ４

ｍ

Ｌ ｏ ●Σ

詐・ｍ︵３ ︶ ﹂ｏ ■ ｏ Ｌ螂＾■ ︶ 一● ３ ｏ Ｌ

o S‐ 1o S‐ 1●S 2● S‐ 3

o

● S‑4

0

250 500 75010001250

Meon Forco (N)S ubj:lSO(notlonQl)

Fig.6 tean force (MF)-mean velocity(MV) relation (lower) and MF-rean
power (MP) relation (upper) obtained fror measurenents rith five different
inertia loads for elite (right) and district (1eft) lifter groups.

Funato, Matsuo, Fukunaga

56

﹇ 一

300

ｏ ・
ｏ 一Ｏ Ｃ Ｏ ︼０ ０ ｃ Ｏ Ｅ Ｌ Ｏ 一﹄ ● α︵一 メ ︶

400

200

All Jopon
Senior

J!nior
100

500

1000

1500

／Ｆ

︻ 一一 ｏ・工ｏ一ＯＣｍ︼
ヒ﹂０﹂ヽＯＬ＾︒工︶ ●ｏＣｏ´

Mecn PoweriL=101(W)
400

/

300
200
100

0

1500

0

1500

MeOn POWer(W)Mlon Power(w)〔S,2.L・ 10kl〕:S・ 3.L・ 10k9】

0

1500

M.on Pow.r (w)tS:1, L.l0 k g I

Fig.? lelationships betreen rean porer (MP) and athletic perfomance (snatch+clean&jerk) in reightlifting. In the lorer panels, values are plottedirrespecive of the perforEance ievel (elite and district).

fer second. fith these iquipoents, horever,nono-articular oove[ents such as flexion or
extension of elbor or knee joint rerestudied for elucidating the characteristics
of nuscle itself from externaly neasured[echanical variables.
Vertical jump testu' 3' i' ' r r) , on theother hand, have veen conuonly used forevaluating the poyer developed during[uIti-articular oovenent. In this method,
it is difficult to obtain any inforrati.on

about the characteristics of porer in
relation to velocity or force, because load
is restricted by the subject's body mass
against gravity. In other rords, the porer
developed during the vertical juflp does notalrays reflect the mxi[um potential of thesubject.

In the nesly developed dynamometer "Porer
Processor", force and velocity rere directly[easured for calculating porer, and aIso,
rork, force, velocity and porer exerted

during an explosive trulti-articular
nove0ent could be obtained under various

inertia load conditions.
Iean porer recorded inS - I condition
shored higher value than that reported in a[axi[u[ acceleration pedalling5 '!'), butlorer than the instantaneous porer exerted
during reightlifting rovement rhich
calculated fron high speed film analysis of
the barbell elevation speed'o) (ranging
fron ca. 1400f to 4000f) and vertical jurp
(ca. 3000 to 4000I)'"
In the elite group, maximm [ean porer ras
developed under the load of l0kgr in S - I
and S - 2 conditions, on the other hand,[axiBull values in S - 3 and S - 4
condition ras reached under the loads oflskgr and 5kgr, respectively (Fig.5). ThisMechanical Power Developed during Simulated Pull Movement inWeightlifting

difference Eay be caused by the differencein force-velocity characteristics of thenajor uuscle groups responsible for each[ovement. The uean force-uean velocity andrespectively, in the district levelreightlifters. These irply the segEental
contribution"' to the total rork liberated
during a si[ulated rho].e pull novenent( S -articular move[ent'6). There have been fer

I ). In the elite reightlif ters,
contribution of leg extension (S - 2 ) ras
targer and that of hip extension (S - 3 )studies that have drarn the force-velocitypoffer re lat ions from hunan moveme n t s
involving t*o or [ore joints'3' 'u). Becently,
evidence for the validity of describing theforce-veLocity relationship for a nultisegnent [ovement (vertical juop) rith

district reishtlifters. {ork made during S- I movenent significantly correlated torork nade during S-2, S-3 and S-4
movements in both elite and district groups.
These observations suggest that the le8

the [ean force-mean porer relations appeared
to be similar to those obtained fron [ono-varying loads has been presented") It has
been argued that the optimr load (specificmtching of force and velocity) for uaxinul
porer generation i.s not unique, but depends
on various rulti-articular [ov e[ en t
condi tions.
Xean and peak porer developed during thesinulated pull noveoent (S - I ) veresignificantly correlated to the athleticsas smaller than those, respectively, in theextension [ove[ent plays a crucial role indeter[ining the aoount of rork liberated

during S - L

and t here fo re theperforuance in the reightl ifting.
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375

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