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1 Department of Neurophysiology, Institute of Medical Physiology and 2 Anatomy Department C, Panum Institute, University of Copenhagen; 3 Copenhagen Muscle Research Centre, Rigshospitalet; 4 Team Danmark Test Centre, Sports Medicine Research Unit, Bispebjerg Hospital, DK-2200 Copenhagen, Denmark
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ABSTRACT |
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 TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
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Combined V-wave and
Hoffmann (H) reflex measurements were performed during maximal muscle
contraction to examine the neural adaptation mechanisms induced by
resistance training. The H-reflex can be used to assess the
excitability of spinal 
-motoneurons, while also reflecting
transmission efficiency (i.e., presynaptic inhibition) in Ia afferent
synapses. Furthermore, the V-wave reflects the overall magnitude of
efferent motor output from the -motoneuron pool because of
activation from descending central pathways. Fourteen male subjects
participated in 14 wk of resistance training that involved heavy
weight-lifting exercises for the muscles of the leg. Evoked V-wave,
H-reflex, and maximal M-wave (Mmax) responses were recorded
before and after training in the soleus muscle during maximal isometric
ramp contractions. Maximal isometric, concentric, and eccentric muscle
strength was measured by use of isokinetic dynamometry. V-wave
amplitude increased ~50% with training (P < 0.01)
from 3.19 ± 0.43 to 4.86 ± 0.43 mV, or from 0.308 ± 0.048 to 0.478 ± 0.034 when expressed relative to
Mmax (± SE). H-reflex amplitude increased ~20%
(P < 0.05) from 5.37 ± 0.41 to 6.24 ± 0.49 mV, or from 0.514 ± 0.032 to 0.609 ± 0.025 when normalized to Mmax. In contrast, resting H-reflex amplitude remained
unchanged with training (0.503 ± 0.059 vs. 0.499 ± 0.063).
Likewise, no change occurred in Mmax (10.78 ± 0.86 vs. 10.21 ± 0.66 mV). Maximal muscle strength increased
23-30% (P < 0.05). In conclusion, increases in
evoked V-wave and H-reflex responses were observed during maximal muscle contraction after resistance training. Collectively, the present
data suggest that the increase in motoneuronal output induced by
resistance training may comprise both supraspinal and spinal adaptation
mechanisms (i.e., increased central motor drive, elevated motoneuron
excitability, reduced presynaptic inhibition).
M-wave; -motoneurons; skeletal muscle
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INTRODUCTION |
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TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
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IT IS WELL ESTABLISHED that physical activity that incorporates high muscle tensions, i.e., heavy-resistance strength training, can lead to an increase in maximal contractile muscle force. However, the specific mechanisms responsible for this adaptation are not fully known. For instance, the increase in maximal contraction force may not solely be explained by increases in muscle cross-sectional area or volume. Rather, an increased "neural drive" to the muscle fibers contributes to the training-induced increase in maximal contractile force, even in the absence of increases in muscle size (27). Thus not only muscle size and muscle phenotype but also neural innervation are important determinants of maximal contractile muscle strength in vivo.
Numerous reports exist of the morphological changes in human skeletal muscle induced by resistance training. Such changes include increases in anatomical muscle cross-sectional area (2, 29) and physiological muscle fiber area (3, 14, 44), increased percentage 2A fibers with a corresponding decrease in 2X fibers (3, 14), and steeper muscle fiber pennation angles (2). Likewise, the neural adaptation induced by resistance training has been addressed with the use of integrated electromyography (EMG) as an indicator for a change in efferent neural drive. Several investigators have reported increases in integrated EMG after resistance training (1, 27, 29), although not consistently demonstrated in all studies (6, 43). Some of this disparity may be explained by the inherent methodological constraints associated with the recording of surface muscle EMG during maximal voluntary contraction (MVC).
Although the effect of resistance training on muscle morphology has
received considerable examination, less is known about the specific
neural mechanisms responsible for the training-induced increase in
maximal muscle strength. Furthermore, only a few studies have studied
evoked spinal motoneuron responses to examine more closely the adaptive
change in neural function induced by resistance training. The H
(Hoffmann) reflex may be useful to assess motoneuron excitability in
vivo (16, 39), while also reflecting presynaptic inhibition of Ia afferent synapses (18, 30) (Fig.
1). We have previously examined the
modulation in H-reflex excitability during walking, running, and
jumping to address the integration of afferent sensory inflow and
efferent motor output during natural movement in humans (11, 12,
40, 41). The so-called V-wave, which is an electrophysiological
variant of the H-reflex, can be recorded during maximal voluntary motor
efforts (17, 24, 46). The evoked V-wave response may be
used to reflect the level of efferent neural drive from spinal
-motoneurons during maximal muscle contraction (46)
(Fig. 2).
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In the present study, evoked V-wave and H-reflex responses were obtained in the soleus muscle to address the neural adaptation induced by intense heavy-resistance strength training. Previous studies on a cross-sectional basis have demonstrated elevated H-reflex excitability in endurance athletes compared with power and sprint athletes (8, 22, 34). Likewise, increased V-wave responses were observed in sprint athletes and weight lifters compared with sedentary subjects (38, 47). In contrast, lower H-reflex amplitudes and reduced H-reflex gains were observed in ballet dancers compared with physical education students (28, 31). However, such cross-sectional comparisons are difficult to interpret because both V-wave amplitude and H-reflex excitability may also be influenced by anatomical or genetic differences and not by the level of physical activity alone. Only a single longitudinal study has examined the neural effects of resistance training on the basis of the recording of evoked spinal reflex responses (37). However, whereas V-wave amplitude was found to increase in response to 9-21 wk of resistance training, no measurements were performed on the corresponding change in H-reflex excitability or maximal contractile strength (37).
The purpose of the present study, therefore, was to employ combined longitudinal measurements of evoked V-wave and H-reflex responses to examine the neural adaptation induced by intensive heavy-resistance strength training.
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MATERIALS AND METHODS |
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TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
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Subjects. Fourteen male subjects volunteered to participate in the study (body mass 70.3 ± 3.6 kg, height 178.6 ± 5.0 cm, age 25.3 ± 4.7 yr, means ± SD). All subjects gave their informed consent to the procedures of the study. None of the subjects had previously participated in systematic resistance training. The conditions of the study were approved by the local ethics committee.
Electromyography.
After careful preparation of the skin (shaving, abrasion, and cleaning
with alcohol), pairs of surface electrodes (Medicotest Q-10-A, 2-cm
interelectrode distance) were placed at the soleus ~13 cm above the
calcaneus and below the muscle fibers of the gastrocnemius, at the
tibialis anterior ~10 cm below the caput fibulae, and at the
gastrocnemius medial and lateral heads ~7 cm below the caput fibulae.
The actual electrode positions were carefully measured in each subject
to control that pre- and posttraining recording sites were identical.
The EMG electrodes were connected directly to small custom-built
preamplifiers (input impedance 80 M
) taped to the skin (11,
40, 41). The EMG signals were led through shielded wires to
custom-built differential amplifiers with a frequency response of
10-10,000 Hz and common mode rejection ratio >100 dB. The
preamplifiers lowered the impedance, which effectively prevented
movement artifacts.
H-reflex recordings.
The H-reflex is elicited by electrical stimulation of the peripheral
nerve, i.e., tibial nerve in the popliteal fossa for the soleus muscle,
thereby bypassing the influence of muscle spindle sensitivity and
-activation of intrafusal fibers. As a result, the H-reflex response
can be used to assess spinal motoneuron excitability and transmission
efficacy in Ia afferent synapses (Fig. 1). The soleus muscle is
especially convenient for measurement of the H-reflex because the
large-diameter Ia afferents and small-diameter -motoneuron axons
differ considerably in size (39). It is possible, therefore, to electrically stimulate the thickest axonal fibers (i.e.,
the Ia afferents) selectively by using low-stimulus intensity. Additional increase in stimulus intensity causes action potentials to
be elicited also in the slightly thinner axons of the -motoneurons.
V-wave recordings.
Briefly, the origin of the V-wave resides on the following mechanisms:
When a supramaximal electrical stimulus is applied to the tibial nerve
during ongoing soleus muscle contraction, it will elicit action
potentials in all Ia afferents and -motor axons, the latter
traveling to the muscle, where it is recorded as an Mmax.
At the same time, action potentials will propagate antidromically
toward the spinal cord in every single -motor axon (Fig. 2). During
this passage, the antidromic action potentials collide with orthodromic
motor action potentials generated as a result of the descending
voluntary input to the pool of motoneurons. Collision between these
antidromic and orthodromic nerve impulses results in a cancellation of
the two signals, and as a result the H-reflex volley is allowed to pass
to the muscle, where it is recorded as a so-called V-wave (17, 42, 46;
Fig. 2). An increased number of voluntary motor impulses results in an
increased incidence of antidromic collision, which allows more
motoneuron axons to be cleared for passage of the evoked reflex
response in turn manifested by an increase in V-wave amplitude
(46) (Fig. 2). Consequently, the peak-to-peak amplitude of
the V-wave expressed relative to that of the maximal M-wave
(V/Mmax) reflects the amount and frequency of efferent
nerve impulses traveling in -motoneuron axons (46). In
other words, V/Mmax may be taken to reflect the magnitude
of efferent motoneuronal output during voluntary muscle activation.
95% Mmax (typically
2-4) (Fig. 5).
Acceptable test-retest reliability values have previously been reported
for the evoked V response (37).
Measurement of maximal dynamic muscle strength. Maximal isokinetic plantar flexor moments were obtained during slow (30°/s) concentric and eccentric muscle contraction performed in a modified KinCom dynamometer. Subjects were positioned as previously described (see H-reflex recordings, V-wave recordings).
Range of ankle joint excursion was
15° (plantar) to 20° (dorsal)
relative to a 90° ankle angle (neutral position). All plantar flexor
moments were obtained at 90° ankle angle. After a 10-min warm-up
subjects performed four to six submaximal plantar flexion ramps in the
dynamometer, followed by a number of force ramps at maximal voluntary
effort. Visual feedback of the exerted plantar moment was provided
on-line to the subjects on a personal computer screen. This allowed
subjects to perform repeated trials (separated by 45-s rest periods)
until no further improvements in peak moment could be detected
(1). Typically five to seven trials were performed to
fulfill this goal.
Training. Details of the training regime have been reported previously (3). In brief, progressive heavy-resistance strength training was performed for 14 wk in a total of 38 sessions. All training was surveyed and supervised by the authors of the study. The primary training exercise performed was seated calf raises. Other obligatory leg training exercises were hack squats, incline leg press, isolated knee extension, and hamstring curls. Four (weeks 1-10) or five (weeks 11-14) sets were performed for each exercise. Training loads ranged between 3 and 10 repetition maximum load (RM), except for the first 10 days (4 sessions), in which lower loading was used (10-12 RM). Very heavy loadings (4-6 RM) and increased number of sets (ensuring unchanged total work load) were used in the final 4 wk of the study.
Statistics. Data are given as means ± SE unless otherwise stated. All pre- to posttraining changes were evaluated by use of the Wilcoxon signed-rank test for paired samples (two-tailed, 0.05 level of significance).
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RESULTS |
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TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
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Evoked motoneuron potentials.
A short-latency V-wave response was elicited when the tibial nerve was
stimulated with supramaximal intensity during maximal isometric
contraction (Fig. 2). The latency of the evoked V-wave was consistently
identical between successive sweeps (Figs.
3-5). Of the 10 sweeps obtained in
each subject pre- and posttraining, peak-to-peak V amplitude was
determined for the sweep demonstrating the largest M-wave amplitude
(Fig. 4). Typical pre- and posttraining V-wave responses are shown in Fig. 5.
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Maximal muscle strength. Maximal concentric muscle strength increased 23% from 112.2 ± 16.7 to 137.6 ± 10.8 Nm (P < 0.05). Maximal eccentric muscle strength increased 30% from 135.5 ± 18.6 to 175.6 ± 8.2 Nm (P < 0.05). MVC determined in the maximal isometric ramp contractions was found to increase from 120.4 ± 14.9 to 158.5 ± 19.8 Nm (P < 0.05), corresponding to an increase of 20%.
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DISCUSSION |
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TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
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In the present study, evoked V-wave and H-reflex responses were
recorded during maximal muscle contraction to examine neural adaptive
changes induced by resistance training. Elevated V-wave and H-reflex
amplitudes were observed in response to 14 wk of progressive
heavy-resistance strength training. Collectively, these findings were
taken to reflect adaptive neural alterations at both spinal and
supraspinal levels, potentially involving changes in -motoneuron
excitability and descending motor drive.
Changes in evoked V-wave responses with resistance training.
During maximal muscle contraction V-waves were evoked by applying
supramaximal stimulation to the peripheral nerve. The V-wave consists
of a volley of H-reflex impulses that are allowed to reach the muscle
because of the removal of antidromic impulses by collision with
efferent nerve impulses generated by the voluntary motor effort
(17, 46) (Fig. 2). An increase in the level of efferent
motor output will give rise to a proportional increase in the
probability of antidromic collision (46). In consequence, the V-wave can be used to reflect the magnitude of efferent
-motoneuron output during voluntary muscle activation (cf. Fig. 2).
It should be noted that the supramaximal level of nerve stimulation
used during recording of the V-wave causes massive excitation of all Ia
afferent axons in the peripheral nerve. As a result, the evoked V-wave
response will recruit both large and small motoneurons, whereas the
H-reflex primarily rely on the pool of smaller motoneurons (see
Changes in H-reflex excitability with resistance training).
-motoneuron
axons during voluntary muscle activation. Thus the present increase in
V-wave amplitude observed with resistance training was likely caused by
an increase in motoneuron firing frequency and/or increased motoneuron
recruitment, because both result in a direct proportional increase in
the probability of antidromic collision. Upton and co-workers
(46) formulated this into a mathematical expression, which
may be useful to further examine these two factors and their potential
contribution to the changes seen with training. Rearranging their
original equation, the magnitude of the V-amplitude is given by
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(1) |
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(2) |
-motoneuron discharge produced by the volley of incoming
antidromic action potentials (23, 25). However, both the
occurrence and latency of the F-wave varies considerably (5, 19,
25), whereas the V-wave response is highly consistent with a
latency identical to that of the H-reflex (17, 42, 46)
(cf. Figs. 3-5). Moreover, in the human soleus muscle the
amplitude of the V-wave is sizably greater than that of the F-wave,
typically differing by a factor 10 or more (17, 46). It is
not likely, therefore, that the change in V-wave amplitude observed in
the present study was caused by a varying involvement of the F-wave.
Changes in H-reflex excitability with resistance training.
For the first time, H-reflex measurements were used to evaluate the
neural adaptation induced by resistance training. An elevated H-reflex
excitability was observed during maximal voluntary muscle contraction
in response to 14 wk of heavy-resistance strength training (Fig. 6),
suggesting that -motoneuron excitability had increased. The
training-induced rise in H-reflex excitability may have been caused by
an increase in descending motor drive from higher centers (cf.
Changes in evoked V-wave responses with resistance
training), although reduced presynaptic inhibition of Ia afferents
cannot be excluded.
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ACKNOWLEDGEMENTS |
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For the use of laboratory facilities and for valuable help, we express our gratitude to Hanne Overgaard, Birgitte Mollerup, and Benny Larsson at Team Danmark Testcenter. We also thank Professor George A. Brooks and Associate Professor Steve Lehman, Department of Integrative Biology, University of California at Berkeley, for valuable help and support.
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FOOTNOTES |
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The present study was supported by the Danish Research Academy and the Danish Elite Sports Association, Team Danmark.
Address for reprint requests and other correspondence: P. Aagaard, Dept. of Neurophysiology, Institute of Medical Physiology 16.5.5, Panum Institute, Blegdamsvej 3, 2200 Kbh-N, Copenhagen, Denmark (E-mail: p.aagaard{at}mfi.ku.dk).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
First published March 8, 2002;10.1152/japplphysiol.01185.2001
Received 30 November 2001; accepted in final form 22 January 2002.
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REFERENCES |
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TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
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|---|
1.
Aagaard, P,
Simonsen EB,
Andersen JL,
Magnusson P,
Halkjær-Kristensen J,
and
Dyhre-Poulsen P.
Neural inhibition during maximal eccentric and concentric quadriceps contraction: effects of resistance training.
J Appl Physiol
89:
2249-2257,
2000.
2.
Aagaard, P,
Andersen JL,
Dyhre-Poulsen P,
Leffers AM,
Wagner A,
Magnusson SP,
Halkjær-Kristensen J,
and
Simonsen EB.
A mechanism for increased contractile strength of human pennate muscle in response to strength training: changes in muscle architecture.
J Physiol
534:
613-623,
2001.
3.
Andersen, JL,
and
Aagaard P.
Myosin heavy chain IIX overshooting in human skeletal muscle.
Muscle Nerve
23:
1095-1104,
2000.
4.
Almeida-Silveira, MI,
Perot C,
and
Goubel F.
Neuromuscular adaptations in rats trained by muscle stretch-shortening.
Eur J Appl Physiol
72:
261-266,
1996.
5.
Burke, D,
Adams RW,
and
Skuse NF.
The effects of voluntary contraction on the H reflex of human limb muscles.
Brain
112:
417-433,
1989.
6.
Cannon, G,
and
Cafarelli E.
Neuromuscular adaptations to strength training.
J Appl Physiol
63:
2396-2402,
1987.
7.
Carp, JS,
and
Wolpaw R.
Motoneuron plasticity underlying operantly conditioned decrease in primate H reflex.
J Neurophysiol
72:
431-442,
1994.
8.
Casabona, A,
Polizzi MC,
and
Perciavalle V.
Differences in H-reflex between athletes trained for explosive contractions and non-trained subjects.
Eur J Appl Physiol
61:
26-32,
1990.
9.
Chen, XY,
and
Wolpaw JR.
Operant conditioning of the H-reflex in freely moving rats.
J Neurophysiol
73:
411-415,
1995.
10.
Crone, C,
and
Nielsen J.
Methodological implications of the post activation depression of the soleus H-reflex in man.
Exp Brain Res
78:
28-32,
1989.
11.
Dyhre-Poulsen, P,
Simonsen EB,
and
Voigt M.
Dynamic control of muscle stiffness and H reflex modulation during hopping and jumping in man.
J Physiol
437:
287-304,
1991.
12.
Ferris, DP,
Aagaard P,
Simonsen EB,
Farley CT,
and
Dyhre-Poulsen P.
Soleus H-reflex gain in human walking and running under simulated reduced gravity.
J Physiol
530:
167-180,
2001.
13.
Gollhofer, A,
Schöpp A,
Rapp W,
and
Stroinik V.
Changes in reflex excitability following isometric contraction in humans.
Eur J Appl Physiol
77:
89-97,
1998.
14.
Hather, BM,
Tesch P,
Buchanan P,
and
Dudley GA.
Influence of eccentric actions on skeletal muscle adaptations to resistance training.
Acta Physiol Scand
143:
177-185,
1991.
15.
Hopkins, JT,
Ingersoll CD,
Cordova ML,
and
Edwards JE.
Intrasession and intersession reliability of the soleus H-reflex in supine and standing positions.
Electromyogr Clin Neurophysiol
40:
89-94,
2000.
16.
Hugon, M.
Methodology of the Hoffmann reflex in man.
In: New Developments in Electromyography and Clinical Neurophysiology, edited by Desmedt JE.. Basel: Karger, 1973, vol. 3, p. 277-293.
17.
Hultborn, H,
and
Pierrot-Deseilligney E.
Changes in recurrent inhibition during voluntary soleus contractions in man studied by an H-reflex technique.
J Physiol
297:
229-251,
1979.
18.
Hultborn, H,
Meunier S,
Pierrot-Deseilligny E,
and
Shindo M.
Changes in presynaptic inhibition of Ia fibres at the onset of voluntary contraction in man.
J Physiol
389:
757-772,
1987.
19.
Jusic, A,
Baraba R,
and
Bogunovic A.
H-reflex and F-wave potentials in leg and arm muscles.
Electromyogr Clin Neurophysiol
35:
471-478,
1995.
20.
Kamen, G,
Knight CA,
Laroche DP,
and
Asermely DG.
Resistance training increases vastus lateralis motor unit firing rates in young and old adults (Abstract).
Med Sci Sports Exerc
30 Suppl:
S337,
1998.
21.
Llewellyn, M,
Yang JF,
and
Prochazka A.
Human H-reflexes are smaller in difficult beam walking than in normal treadmill walking.
Exp Brain Res
83:
22-28,
1990.
22.
Maffiuletti, NA,
Martin A,
Babault N,
Pensini M,
Lucas B,
and
Schieppati M.
Electrical and mechanical Hmax-to-Mmax ratio in power- and endurance-trained athletes.
J Appl Physiol
90:
3-9,
2001.
23.
Mayer, RF,
and
Feldman RG.
Observations on the nature of the F wave in man.
Neurology
17:
147-156,
1967.
24.
McComas, AJ,
Fawcett PRW,
Campell MJ,
and
Sica REP
Electrophysiological estimation of the number of motor units within a human muscle.
J Neurol Neurosurg Psychiatry
34:
121-131,
1971.
25.
McLeod, JG,
and
Wray SH.
An experimental study of the F wave in the baboon.
J Neurol Neurosurg Psychiatry
29:
196-200,
1966.
26.
Milner-Brown, HS,
Stein RB,
and
Lee RG.
Synchronization of human motor units: possible role of exercise and supraspinal reflexes.
Electroencephalogr Clin Neurophysiol
38:
245-254,
1975.
27.
Moritani, T,
and
deVries HA.
Neural factors versus hypertrophy in the time course of muscle strength gain.
Am J Phys Med Rehabil
58:
115-130,
1979.
28.
Mynark, RG,
and
Koceja DM.
Comparison of soleus H-reflex gain from prone to standing in dancers and controls.
Electroencephalogr Clin Neurophysiol
105:
135-140,
1997.
29.
Narici, MV,
Roig S,
Landomi L,
Minetti AE,
and
Cerretelli P.
Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps.
Eur J Appl Physiol
59:
310-319,
1989.
30.
Nielsen, J,
and
Kagamihara Y.
The regulation of presynaptic inhibition during co-contraction of antagonist muscles in man.
J Physiol
464:
575-593,
1993.
31.
Nielsen, J,
Crone C,
and
Hultborn H.
H-reflexes are smaller in dancers from the royal Danish ballet than in well-trained athletes.
Eur J Appl Physiol
66:
116-121,
1993.
32.
Patten C. Age and training related influences on motor unit
control properties. Proc XVIIth Int Congr Soc Biomech Calgary,
Canada 1999, p. 246.
33.
Perot, C,
Goubel F,
and
Mora I.
Quantification of T- and H-responses before and after a period of endurance training.
Eur J Appl Physiol
63:
368-375,
1991.
34.
Rochcongar, P,
Dassonville J,
and
Le Bars R.
Modification of the Hoffmann reflex in function of athletic training.
Eur J Appl Physiol
40:
165-170,
1979.
35.
Ruegg, DG,
Krauer R,
and
Drews H.
Superposition of H reflexes on steady contractions in man.
J Physiol
427:
1-18,
1990.
36.
Sale, DG,
McComas AJ,
MacDougall JD,
and
Upton ARM
Neuromuscular adaptation in human thenar muscles following strength training and immobilization.
J Appl Physiol
53:
419-424,
1982.
37.
Sale, DG,
MacDougall JD,
Upton A,
and
McComas AJ.
Effect of strength training upon motoneuron excitability in man.
Med Sci Sports Exerc
15:
57-62,
1983.
38.
Sale, DG,
Upton A,
McComas A,
and
MacDougall JD.
Neuromuscular function in weight-trainers.
Exp Neurol
82:
521-531,
1983.
39.
Schieppati, M.
The Hoffmann reflex: a means for assessing spinal reflex excitability and its descending control in man.
Prog Neurobiol
28:
345-376,
1987.
40.
Simonsen, EB,
Dyhre-Poulsen P,
and
Voigt M.
Excitability of the soleus H reflex during graded walking in humans.
Acta Physiol Scand
153:
21-32,
1995.
41.
Simonsen, EB,
and
Dyhre-Poulsen P.
Amplitude of the human soleus H reflex during walking and running.
J Physiol
515:
929-939,
1999.
42.
Stanley, EF.
Reflexes evoked in human thenar muscles during voluntary activity and their conduction pathways.
J Neurol Neurosurg Psychiatry
41:
1016-1023,
1978.
43.
Thorstensson, A,
Karlsson J,
Viitasalo JHT,
Luhtanen P,
and
Komi PV.
Effect of strength training on EMG of human skeletal muscle.
Acta Physiol Scand
98:
232-236,
1976.
44.
Thorstensson, A,
Hultén B,
van Döbeln W,
and
Karlsson J.
Effect of strength training on enzyme activities and fibre characteristics in human skeletal muscle.
Acta Physiol Scand
96:
392-398,
1976.
45.
Trimble, MH,
and
Koceja DM.
Modulation of the triceps surae H-reflex with training.
Int J Neurosci
76:
293-303,
1994.
46.
Upton, ARM,
McComas AJ,
and
Sica REP
Potentiation of "late" responses evoked in muscles during effort.
J Neurol Neurosurg Psychiatry
34:
699-711,
1971.
47.
Upton, AR,
and
Radford PF.
Motoneurone excitability in elite sprinters.
In: Biomechanics V-A, edited by Komi PV.. Baltimore, MD: University Park, 1975, vol. 1A, p. 82-87. (International Ser Biomech)
48.
Van Cutsem, M,
Duchateau J,
and
Hainaut K.
Changes in single motor unit behavior contribute to the increase in contraction speed after dynamic training in humans.
J Physiol
513:
295-305,
1998.
49.
Voigt, M,
Chelli F,
and
Frigo C.
Changes in the excitability of soleus muscle short latency stretch reflexes during human hopping after 4 weeks of hopping training.
Eur J Appl Physiol
78:
522-532,
1998.
50.
Wolpaw, JR.
Operant conditioning of primate spinal reflexes: the H-reflex.
J Neurophysiol
57:
443-459,
1987.
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3) will collide with the
antidromic action potentials (response 1*), thus allowing a
part of the evoked reflex response to pass to the muscle (2 
