東京大学教養学部体育学紀要 (1● 94)然 , 31〜 3S

Heterogeneity of Fiber Types in Human Observed
3'P NMR Spectroscopy during Exercise.
Shin-ya Kuno and Shigeru Katsuta*
Dept. of Sports Sciences, College of Arr aod Science,

The University of TokyoaDd lostitute of Health and Sporr Scie[ces,University of Tsukuba t:

Abslract
Phosphours ouclear magnetic resoDance ( slf MvIR; spectrGcopy was used to evaluate

the relationship betwe€n changes in the concentrations of muscular phosphate metabolites
duriDg exercise aod reco',,ery and muscle fib€r compositioo of M. Vastus lateralis in human.
The subjects,rere dMded in rhe rbree fiber type groups (Slo\ group ;{N fo Ff fibeN,
D = 8, Inte.mediate group ; from 40 to 6l Ea Ff fibers, n: 16, Fasr grotp ;)tfi
V" F'lfibers, n : 6). The fasr group sho\ir'ed a significanrly lo\ir'er PCr / pi rutio rhaD rhose of
the intermediate and slow group at the first minute of exercise. This tendenry was alsoobserved after the first miDute of exercise and during recovery. The slortr group sho\xed thehighest recovery rate irl the PCr / Pi ratio during the first minute after the exercise. On
the other ha[d, the fasr group showed rhe slowesr recovery- lt is suggested that pcr / pi,ratio duriDg exercise and recotr'ery by 3lP NMR relates ro rhe differences io muscle libertypes.

3lP NMR, muscle energetics, phosphocreatinc, cxercise, musclc libcr types

Heleroglneit-! ol fiber lyp.x in hunatr otsered 3I P NMR speclros.opy duing exercise.

32

lntroduction
Muscle is composed of two types of fiber vr'ith

opposite characters, i,e., Iast-twitch (FT) at
slowtwitch (ST) fibers. The ratio of these twotypes (muscle fiber composition) is closely
related to aptitude of sport eventsa'3). The
biopsy had been only one modality to determine

muscle fiber composition in human. The
development of a noninvasive approach could
be valuable to the field of sport science andmedicine.

Nuclear magnetic resonace (NMR)
noninvasively provides information on
mbtabolites which has not been obtained in vivo

20-26 years, ranging in height from 165.2-180.

scm (mean=171.7cm, SD=4.6) and in weightfrom 60.4 to 75.5kg (mean:68.2kg, SD:4.9).
Informed consent to partici-pate in the study
was obtained from all subjects.
Muscle type.

The needle biopsy specimens (about 20mg)
were taken from the quadriceps fenoris muscle(musclus vastus lateralis) by an orthopedic
surgeon. The biopsy site was 35-40% of thedistance from the superior margin of patella tothe anterior superior illac spine. The samples
were immediately frozen in lsopentance andcooled by liquid nitrogen. From histochemical
analysis, sequential 10-pm sections were cut ina cryostat maintained at -20"C , and stained for
myofibrillar ATPase activity. Based on theby conventional methods. Recently, there aresome reports on the use of NMR'z,63,rs). Using
magnetic resonance imaging (1H-MRI), we
have found an extremely high correlation
between magnetic resonance relaxation time(T1) and muscle fiber composition by biopsyr'sl.
On the other hand, we indicated no definite

and ST. We counted the 400-600 fibers foreach subject to decide the muscle fiber

relationship between phosphocreatine (PCr) /composition.

inorganic phosphate (Pi) bv "P NMR
spectroscopy at rest and fu FT fibersT). SomegruopsrJ'z) examined that the relationshipbetween fiber types and the split peaks of Pi
observed rvith 3'P NMR spectra during
exercise. They suggested that it might bepossible to charactetize fiber types. However,in these studies, whether the 3IP NMR results
actualiy reflected muscle fiber compostition it

ATPase staining after pre-incubation (pH 10.3),
fibers were classified into trMo main types, FT

According to the muscle fiber composition ofM. vastus lateralis determined, the subjects
were classified into 3 groups : fast group(predominantly FT fibers, >60% FT fibers),
intermediate group. (from 40 lo 600/0 FT fibers),
slow group (predominantly ST fibers, (40!lFT fibers).
3IP NMR.
3'P NMR spectoroscopy weredone more than

was not confirmed by muscle biopsy.

1 month after muscle biopsy. All subjects

ln the present study, using 3rP NMR during
exercise and recovery, we investigated therefrained from exercise for 24hours before thestudy. A spectrometer (Signa; GE MedicalSystems, Milwaukee, U.S.A.) was used with asuperconducting magnet at 1.5 Tesla with 60cm
boreT). 3rP NMR measurements were performed
at 25.9MHz with a 3.5inch diameter (transmit)
surface coil placed on the right M. vastus
lateralis. That position was fixed to allow
biopsy site at the coil center. NMR spectra
were collected by accumulating 6 transientswith a recycling time of 3.5 sec. Quantification

relationship between phosphorus metabolites ofhuman muscle and fiber types in the subjects

whose muscle fiber composition had been
determined by biopsy.
Methods
Subjects

The subjects in this study wer 30 male ofstudents (specialized physical education), ages

HererogeDeity of fiber types io human obseNed

3tP NMR spe.r.o6copy duirg exeEise.

Ｉ出Ｆ←︱１ ０ ¨和Ｓｉｌμｂ３ll︱贄 γl・２・ｌざ ←the PCr/Pi ratio. Measurement of NMR wascarried out continuously from the resting
period to the exercise period ({ min) and theこ ヽ Ｏαsec. Changes in PCr and Pi were evaluated as︱ ＝ 共 同 Ｊ■＝日精＝︱

saturation factors obtained by a comparison ofpeak area was calibrated using the saturation
factors obtained by a comparison of peak areas
measured with recycling times of 3.5 sec and 15

可淵 ＝ 嚇 針 １of metabolites was carrid out by integrating
NMR peak areas. To avoid the partial

33

recovery period (5 min). The subjects lay in the４Ｅon the right ankle and lifted the ankel with theＲsupine position witi a weight about I kg fixed2046̀●・l。

)

RooOVeryknee extended at a rate of 60 times per minuteFig.l Changes of PCr/Pi during exercise (4for 4 minutes. Care was taken to make themin)and recovery (5 min) on the differentfiber type groups. Values are meanstSD.

distance of each lifting uniform.
Results

The determined {ast, intermediate and slow

groups by muscle biopsy consisted of sixfor one minute, A SIow group (29.1+5.1%FT fibers;n=8), O Intermediata group(46.$+5.ifuFT fibers;n = 16), a Fast sroup(71.9+11.1 %FT fibers;n=6),: p< 0.05

subjects (meantSD values= 74.9117.1% FTfibers), sixteen subjects ({6.815.1% FT fibers)

ST fibers by NMR. Using "P NMR, Chance'sand eight subjects (29.1+5.1% FT fibers),
respectively. The % FT fibers of Fast gruop
has a significant difference (p<0.05) fromgroupr'z) found that inorganic phosphate (Pi)intermediate and slow groups and the one ofintermediate group also in higher than slow
group (p< 0.05).

intracellular enyironments of the FT and ST
fibers. These findings were also supported by
Achten et all) . On the other hand, we focused

Figure 1 shows changes in the PCrlPi ratio inon the relaxation tirne calculated fromthe three groups before, during and afterexercise. During the first minute of exercise,the fast group showed a significantly lower

shows two peaks during exercise and suggested

that these peaks indicated different

lH-magnetic resonance imaging (MRI) and0.05). This tendency was also observed after thefound that the relaxation time at rest was
related to the muscle fiber compositionr's,.
However, the relationship between muscular
metabolism during exercise and muscle fiber

first minute of exercise and during recoyery.

composition by biopsy has not been

The slow group showed the highest recovery

investigated so far.

rate during the first minute after

ln this study, the fast group showed asignificantly lower PCr/Pi ratio than those of
the intermediate and slow groups at the firstPCr/Pi ratio than did the other two groups (p<discontinuation of exercise, and the fast group
showed the slowest recovery.
Discussion

Several research groups'''z) have reported
differences in metabolism between the FT andminute of exercise. This tendency was also
observed during the subsequent period ofexercise and recovery. FT fibers have low
aerobic capacity and use glycolysis as a main

ATP source and produce many protonsl'). It isestablished that FT fibers have higher creatine
kinase activity and, hance, higher Pi
concentrations during exercise, and that therecovery is slower than ST fibers'3). It isreasonable, therefore, that the ratio of PCr/Piof fast goup is lowest during exercise as wasshown in this study.
The ATP demand decreases, immediately
after the exercise discontinues, ATP is mainly
used for phosphorylation oI creatine to PCr.
Since ATP is produced by gxidation after
exercise, recovery of the PCr level reflects theoxidative faculty during exercise'ru''u). In
particular, recovery o{ the PCr level in theinital stage of recovery is attributable to theresynthesis of ATP in mitochondriar.). The
higher PCrlPi of the slow group than that of
the fast group at the first minute of recovery
suggests that the slow group preserved a higher
faculty for mitochondrial respiration. This ishighly likely in view of the higher oxidative
faculty in the slow group than that in the fastgroup.

In conclusion, determination of the PCr/Pi
ratio classified according to the muscle fiber
composition during exercise and recovery
revealed that the ratio in the fast group waslowest in both periods, reflecting differences in

the metabolic properties of FT and ST fibers.
Since 3'P NMR used in this study permits
noninvasive measurement of phosphorus
metabolites and quantification of differences infiber composition, it is suggested that the ratioof PCr/Pi by 3'P NMR can be used to predict
the three fiber t,?e groups.

Physiol., 68, 644-649.

2. Chance, 8., Sapega, A., Sokolow, D., Elef, S.,
Leigh, J. S., Graham, T., Armstrong, J., andWarnell, R.(1983) Fatigue in retrospect andprotospect : "'P NMR studies of exerciseperformance. In:Biochemistry of Exercies, Ed.
Kunttgen, H. G., Vogel, J. A. and Poortmans, J.,
Human Kinetics, Chicago, vol 13, 895-908.

3. Gollnick, P. D., Armstrong, R. 8., Saubert, C.
W., Piehl, K.,and Saltin, B. Enzyme activity andfiber composition in skeletal muscle ofuntraihed and trained men. J. Appl. Physiol., 33,

4. Kuno, S., Katsuta, S., Inouye, T., Anno, I.,
Matsumoto, K., and Akisada, M.(1988)
Relationship between MR relaxation time andmuscle fiber composition. Radiology, 169,
567.568.

5. Kuno, S., Katsuta, S., Akisada, M., Anno,I., andMatsumoto, K. (1990) Effect of strength training
on the relationship between magnetic resonancerelaxation time and muscle fiber composition.
Eur. J. Appl. Physiol., 61, 33.36.

6. Kuno, S., Akisada, M., katsuta, S., andMitsumori, F. (1990) EYaluation of exercise
muscle energetics by NMR. Ann. Physiol.
Athrop., 9, 235-239.

7. Kuno, S., Akisada, M., Anno, I., Niitsq M., Itai,Y. and Katsuta, 5.(1991) Heterogeneity ofmuscle energetics in human muscle fibertypeusing P NMR. Clin. J. Sports Med., 1,247-250

8. McCully, K. K,. Kent, J. A., and Chance, 8.(1988)
Application of !rP magnetic resonancespectroscopy to the study of athletic
performance. Sports Med., 5, 312-321.

9. McCully, K. K., Boden, B. P., Tuchler, M.,
References

Fountain, R., and Chance, 8.(1989) lvrist flexor

1. Achten, E., Cauteren, M. V., Willem, R.,
Luypaert, R., Malaisse, G. V., Bsch, G. V.,

muscles of elite rowers measured with magnetic
resonace spectroscopy. J. Appl. Physiol., 62,Delanghe, G., Meirleir, K.D., and Osteaux, M.
(1990) !rP NMR spectroscopy and t}le metabotic

10. Meyer, R. A., Brown, T. R., and Kushmerick, M.

properties of different muscle fibers. J. Appl.

J. (1985) Phosphorus nuclear magnetic

926-932.

Heterogeneity of fib€r types ir hunao obseNed 31p NIr n .p""t,"*py dttins eErcise.

resonance of fast- and slo{-twitch muscle. Am.

J. Physiol., 248, C279-C287.
11. Nagata, A., Muro, M., Moritani, T. and YoshidaT. (1981) Anaerobic threshold determination byblood lactate and myoelectric signals. Jpn. J.
Physiol., 31,585- 597.
12. Park, J. H., Brown, R. L., Park, C. R., McCully,K., Cohn, M., Haselgrove, J., and Chance, B.
(1987) Functional pools of oxidative andglyco)itic fibers in human muscle observed by "'P magnetic resonance spectroscopy during
exercise. Proc. Nati. Acad. Sci. USA, 84,8976-8980.

13. Peter, J. 8., Barnard, R. J., Edgerton, V. R.,

Gillespie, C. A., and Stemple, K. E.0972)
Metabolic profiles of three fiber types ofskeletal muscle in guinea pigs and rabbits.
Biochemistry, 11, 2627 -2633.
14. Saltin, 8., Gollnick, P. D-(1983) Skeletal muscle

adaptability- Significance for metabolism andperformance. In Handbook of Physiology-Skkeletal muscle. Am. Phlsiol. Soc., NewYork,555-621.
15. Taylor, D..J., Bore, P. J., Styles, P., Gadian, D.

G., and Radda, G. K.(1983) Bioenergetics ofi[tact human muscle. -A "P nuclear magnetic
resonance study. Mol. Biol. Med., 1, 77-94.
16. Taylor, D. J., Styles, P., Matthews, P. M.,

Arnod, D. A., Gadian, D. G., Bore, P. J., andRadda, G. K.(1986) Energetics of human muscle:

exercise induced ATP depletion. Magn. Reson.
Med., 3, 44-54.