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148
Journal of Strength and Conditioning Research, 2003, 17(1), 148–155
q 2003 National Strength & Conditioning Association
Force-Velocity Analysis of Strength-Training
Techniques and Load: Implications for Training
Strategy and Research
JOHN B. CRONIN,1 PETER J. MCNAIR,2 AND ROBERT N. MARSHALL3
1Sport Performance Research Centre, Auckland University of Technology, Auckland 1020, New Zealand;
2Neuromuscular Research Unit, School of Physiotherapy, Auckland University of Technology, Auckland 1020,
New Zealand; 3Eastern Institute of Technology, Taradale, New Zealand.
ABSTRACT
The purpose of this study was to investigate the force-veloc-
ity response of the neuromuscular system to a variety of
concentric only, stretch-shorten cycle, and ballistic bench
press movements. Twenty-seven men of an athletic back-
ground (21.9 6 3.1 years, 89.0 6 12.5 kg, 86.3 6 13.6 kg 1
repetition maximum [1RM]) performed 4 types of bench
presses, concentric only, concentric throw, rebound, and re-
bound throw, across loads of 30–80% 1RM. Average force
output was unaffected by the technique used across all loads.
Greater force output was recorded using higher loading in-
tensities. The use of rebound was found to produce greater
average velocities (12.3% higher mean across loads) and
peak forces (14.1% higher mean across loads). Throw or bal-
listic training generated greater velocities across all loads
(4.4% higher average velocity and 6.7% higher peak veloci-
ty), and acceleration-deceleration profiles provided greater
movement pattern specificity. However, the movement veloc-
ities (0.69–1.68 m·s21) associated with the loads used in this
study did not approach actual movement velocities associ-
ated with functional performance. Suggestions were made as
to how these findings may be applied to improve strength,
power, and functional performance.
Key Words: bench press, stretch-shorten cycle, contrac-
tile component, elastic component
Reference Data: Cronin, J.B., P.J. McNair, and R.N.
Marshall. Force-velocity analysis of strength-training
techniques and load: implications for training strategy
and research. J. Strength Cond. Res. 17(1):148–155. 2003.
Introduction
The force-velocity relationship characterizes the dy-namic capability of the neuromuscular system to
function under various loading conditions and, there-
fore, has considerable significance in the performance
of movement (11). Understanding how various acute
program variables and their interactions affect either
force or velocity would seem important in determining
how to alter the performance capability of muscle for
a given purpose. However, there is very little pub-
lished information on the effects of regular exercise on
this relationship. Research that does investigate veloc-
ity-related force production typically uses isokinetic
testing and training paradigms. However, this type of
muscle action does not simulate the natural move-
ments of the body, which include accelerations, decel-
erations, and eccentric stretching phases before the
concentric or shortening phases. As such, the external
and logical validity of findings from isokinetic re-
search would appear questionable.
Isoinertial assessment (constant gravitational load),
however, does not suffer the same problems with va-
lidity because this type of motion simulates the move-
ment patterns encountered in everyday and sporting
activities better. However, little attention has been paid
to the effect of different techniques and loading inten-
sities on the development of force and velocity using
isoinertial assessment (1). The effects of various deri-
vations and combinations of the traditional bench
press on a variety of kinematic and kinetic measures
have been studied by Newton, Wilson, and colleagues
(21–24, 30, 31). These researchers have found explosive
techniques that allow the load to be projected, as in a
throw or jump, produced higher velocity, acceleration,
force, and power. Such training has been described
‘‘ballistic’’ and allows the individual to accelerate the
load through most of the movement (21). Supple-
menting this technique with rebound, i.e., using an ec-
centric muscle action to augment the concentric con-
traction (stretch-shorten cycle—SSC), produced great-
er initial impulse, higher peak bar velocities, and high-
er accelerations throughout the range of movement,
and increased work and power. A limitation of this
research, however, is that the effects of the different
bench press techniques and loads were not investigat-
ed in a single research. That is, to gain a complete
Force-Velocity Analysis of Strength Training 149
understanding on the effect of SSC, load, or projection
of the bar, one must compare and extrapolate the find-
ings across laboratories, with different subjects using
different procedures. To negate the problems inherent
in such an approach, the interaction between technique
and load needs to be investigated in a single para-
digm. This study, therefore, compared 4 isoinertial
weight-training techniques across loads ranging from
30 to 80% 1 repetition maximum (1RM). Increasing
load would increase force and decrease velocity across
techniques. Although the interaction between contrac-
tion type, movement, and load is difficult to predict,
it was thought that ballistic techniques that used re-
bound would result in greater force and velocity as
compared with the other techniques. Understanding
the effects of these factors on the performance capa-
bility of muscle should allow for better training pre-
scription.
Methods
Experimental Approach to the Problem
Subjects visited the laboratory on 2 separate occasions.
The first visit involved familiarization with the 4 dif-
ferent bench press techniques and determination of
each subject’s bench press 1RM. During the next ses-
sion, the 4 bench press techniques were performed for
6 training loads (30, 40, 50, 60, 70, and 80% 1RM).
Thereafter, the interactions between technique and
load were statistically analyzed.
Subjects
Twenty-seven men volunteered to participate in this
research. The subjects’ mean (6SD) age, weight, and
maximal bench press strength (1RM) were 21.9 6 3.1
years, 89.0 6 12.5 kg, and 86.3 6 13.7 kg. All the sub-
jects were from an athletic background (principally
club rugby players); however, no subject reported us-
ing strength training in the previous 6 months. The
Ethics Committee of the University of Auckland ap-
proved all the procedures used, and the subjects pro-
vided informed consent to participate in the study.
Equipment
Modified Smith Machine. Subjects performed bench
presses on a modified Smith press machine. A linear
transducer (Unimeasure, Corvallis, OR) was attached
to the bar. This transducer measured bar displacement
with an accuracy of 0.1 cm. Bar displacement data
were sampled at 200 Hz and relayed to a computer-
based data acquisition and analysis program. Dis-
placement time data were filtered using a low-pass fil-
ter with a cutoff frequency of 10 Hz. Validation of the
linear transducer with a force platform (AMTI Force
Plate and Amplifier; Advanced Medical Technology
Inc., Watertown, MA) has been studied previously.
Measures of peak force, mean force, and time to peak
force were gathered from both pieces of equipment for
a variety of jumps. No intraclass correlation coefficient
was less than 0.92 and most ranged between 0.97 and
0.99. The reliability of this system has been reported
in earlier research (6).
The filtered data were differentiated using a finite
differences algorithm to determine velocity and accel-
eration data. The force data were determined by mul-
tiplying the mass by the acceleration data. The concen-
tric phase of the rebound bench press (RBP) and RBP
throw (RBPT) was determined at the time when bar
velocity changed from positive to negative. For the
concentric-only benchpress (BP) and concentric throw
(BPT), the start of the concentric phase was deter-
mined as the point at which the vertical force in-
creased (23). Average velocity, peak velocity, peak ac-
celeration, average force, peak force, and the duration
of concentric action during the concentric phase were
calculated for all techniques and loads. The duration
of the eccentric phases was calculated for the tech-
niques that used rebound.
Determination of 1RM Bench Press and Familiariza-
tion
The testing procedures used in this research were sim-
ilar to those outlined by Newton et al. (23). A repeti-
tion to failure protocol was used to determine each
subject’s maximal bench press strength. At the com-
pletion of the 1RM testing, subjects performed a num-
ber of bench presses to familiarize themselves with the
power movements. For BP, a mechanical brake was po-
sitioned so that the bar rested approximately 5 cm
above each subject’s chest, parallel to the nipples. The
bar was then projected from rest as fast as possible
and was either held at the end of the movement or
thrown. For RBP, subjects were instructed to begin
with the weighted barbell at arm’s length and lower
the bar as quickly as possible to just above the nipples,
and then immediately push the bar upward. The bar
was either held at the end of the movement or thrown.
Bench Press Assessment
The second session began with a generalized warm-
up of arm- or shoulder-mobilization exercises, 2 sets
of 10 repetitions at 40% of the 1RM, followed by 5
minutes of pectoral and triceps brachii static stretches.
The subject was strapped on the bench and was in-
structed to move the bar as fast as possible for all loads
and movement types. Four movements were per-
formed for 6 training loads (30, 40, 50, 60, 70, and 80%
1RM). The 4 movements were a concentric bench
press, a concentric bench press throw, a concentric
bench press preceded by an eccentric contraction, and
an eccentric-concentric bench press throw. One trial
was completed per movement type and load, and rest
periods of a minute between each explosive movement
and 2 minutes between change of loads were provid-
ed. For the rebound movements, no pause was allowed
150 Cronin, McNair, and Marshall
Figure 1. Average force (N) at different loads relative to 1 repetition maximum for 4 different explosive weight-training
techniques.
between the eccentric and concentric phases, and the
trial was rejected if the bar touched the chest in any
manner or the eccentric phase was terminated greater
than 5 cm from the chest. Starting loads and move-
ment types were randomized between subjects to re-
duce the possible confounding effects of order and fa-
tigue before the proceedings. The reliability of this
procedure was established in pilot testing. Data for 1
and 3 trials were assessed within and across days. In-
traclass correlation coefficients of 0.85–0.99 were cal-
culated for the variables peak and average velocity,
and peak and average force.
Statistical Analyses
The results for mean velocity, peak velocity, peak ac-
celeration, average force, and peak force were com-
pared using a 2 3 2 3 6 repeated measures analysis
of variance (contraction, movement, and load). Post
hoc contrasts were used to determine significant dif-
ferences between the means. The criterion level for sig-
nificance was set at p # 0.05 and was adjusted using
the Bonferroni procedure if more than one post hoc
contrast was needed.
Results
It is worth noting the limited weight-training experi-
ence of the subjects as denoted by the relationship of
their maximal bench press strength (86.3 kg) to their
body mass (89.0 kg). Furthermore, the rebound bench
press movements investigated are an example of slow
(.250 ms) SSC motion (28); therefore, the application
of the findings to faster SSC movements is not implicit.
The interpretation and discussion of the present find-
ings should be considered with these limitations in
mind.
It can be observed from Figure 1 that there was no
significant difference in average force output between
the various techniques at all loads. However, as load
increased so did average force (p , 0.05). A 10% in-
crease in load corresponded to a 20% increase in force
output on average across all loads. The load of 80%
1RM produced the greatest average force output
across all techniques.
The relationship between load and peak force is
similar in that greater peak forces are recorded with
higher loading intensities (see Tables 1 and 2). Al-
though there was no significant difference in peak
force between held and throw conditions, the rebound
technique produced significantly higher peak forces
across all loads (14.1%) compared with the concentric-
only movements. The effect of rebound was to produce
higher initial accelerations, which ultimately affected
force.
For loads of 30–60% 1RM, throw techniques pro-
duced greater average and peak velocities (4.4 and
6.7%, respectively) than did techniques that held the
bar at the conclusion of the concentric phase (see Fig-
ure 2). The potentiating effect of the throwing motion
was found to be insignificant when using heavier
loads of 70–80% 1RM. Motion that used rebound pro-
Force-Velocity Analysis of Strength Training 151
Table 1. Mean values 6 SD for peak velocity (PV), peak force (PF), time to peak velocity (TPV), and duration of concentric
contraction (DOCC) for concentric only bench presses at loads ranging from 30 to 80% 1 repetition maximum.
%
1RM
Concentric bench press
PV (m·s21) PF (N) TPV (s) DOCC (s)
Concentric bench press throw
PV (m·s21) PF (N) TPV (s) DOCC (s)
30
40
50
60
70
80
1.49 6 0.15
1.35 6 0.15
1.16 6 0.13
1.01 6 0.13
0.86 6 0.12
0.68 6 0.16
414.1 6 74.7
505.9 6 82.8
583.8 6 84.9
660.9 6 99.4
766.4 6 151.9
826.3 6 138.2
0.401 6 0.049
0.459 6 0.048
0.528 6 0.057
0.620 6 0.083
0.774 6 0.129
0.928 6 0.420
0.629 6 0.052
0.683 6 0.056
0.761 6 0.068
0.818 6 0.077
0.964 6 0.124
1.12 6 0.186
1.63 6 0.15
1.45 6 0.14
1.27 6 0.12
1.05 6 0.11
0.89 6 0.15
0.72 6 0.12
411.1 6 75.9
505.2 6 78.9
589.2 6 87.9
657.3 6 91.7
772.8 6 139.6
820.5 6 120.9
0.429 6 0.047
0.495 6 0.061
0.547 6 0.057
0.648 6 0.065
0.771 6 0.11
1.010 6 0.207
0.792 6 0.066
0.816 6 0.069
0.826 6 0.065
0.883 6 0.075
0.953 6 0.111
1.210 6 0.203
duced greater average velocities (12.3%) across all
loads. As load increased, average and peak velocity
were found to decrease; the lowest average and peak
velocities for all bench press techniques occurred at
80% 1RM. Higher peak velocities were recorded for
techniques that used projection or release of the load.
The effect of rebound on peak velocity across all loads
was nonsignificant (see Tables 1 and 2).
Greater loads affected the temporal characteristics
of each technique in a predictable and similar manner.
As load increased so did the duration of the eccentric
and concentric phases of the respective contractions.
The time required for achieving peak velocity also in-
creased as a function of load. Also, if the RBP and CBP
are compared, motion that uses rebound is terminated
earlier.
Discussion
The force-velocity relationship of muscle dictates that
the faster the velocity of concentric muscle action, the
lower the force that can be produced. This has been
attributed to the increased rate of cross-bridge attach-
detach cycling, which equates to less time to generate
tension for force production (14) and greater internal
resistance or viscosity that equates to loss of force (4).
One can observe this relationship from Figures 1 and
2, i.e., the decreasing velocity of concentric muscle ac-
tion and increasing force output, with increasing load.
Average force output was unchanged between ex-
plosive techniques for a given loading intensity. The
role of rebound and release had no effect on concentricaverage force production. This conflicts with the find-
ings of Newton et al. (23) who found greater average
force across loads when comparing an SSC bench
press throw with a concentric-only throw. Because re-
bound was found to produce greater peak accelera-
tions and, therefore, peak forces, it would be assumed
that greater average force would result. However, the
effect of the greater peak force generated during the
rebound bench presses appeared to have a negligible
effect on average force production. This finding could
be explained by the force-velocity relationship, as the
velocity enhancement occurring due to rebound and
release may be lost due to the inability of the muscle
to generate force at higher shortening velocities. The
findings could also be explained by peak force occur-
ring very early during the concentric contraction, and
the benefits of prestretching a muscle are lost if the
movement continues over too long a time period. For
example, very long stretching phases (approximately
500 ms) are associated with long coupling times (tran-
sition from eccentric to concentric contractions) and
loss of elastic energy (2). Both the eccentric and con-
centric phases of all bench press techniques, across all
the loads used in this study, exceeded 500 ms. Finally,
the similar average force between the concentric-only
and rebound techniques could be attributed to early
termination of the concentric phase associated with
motion that uses prestretch (23).
Although the exact mechanism by which strength
training elicits enhanced net synthesis of contractile
proteins to increase the cross-sectional area (CSA) of
muscle is yet to be determined, it is thought that both
active and passive muscle tensions initiate this process
(10). MacDougall (18) stated that whatever the exact
mechanism for stimulating protein synthesis, loading
intensity is the main determinant of whether incre-
ments in strength and size will occur. He continued to
state that muscle must be activated at an intensity of
at least 60–70% of maximum force-generating capacity
before an increase in total muscle size and, hence,
strength occurs. If muscle growth and contractile
strength are related to the amount (load-tension) and
time that tension is developed within the muscle (12),
it would seem that the slower velocity training asso-
ciated with higher 1RM training would be a better al-
ternative for hypertrophic adaptation. Such loading
augments both the duration of the stimulus (DOE and
DOC) and the tension developed (average force) thus
favoring a greater development of strength and muscle
mass. This is not novel information. However, the use
of SSC training to produce greater strength and CSA
adaptation may warrant investigation. That is, the net
effect of motion using SSC (RBP and RBPT) was to
152 Cronin, McNair, and Marshall
Ta
bl
e
2.
M
ea
n
va
lu
es
6
SD
fo
r
pe
ak
ve
lo
ci
ty
(P
V
),
pe
ak
fo
rc
e
(P
F)
,t
im
e
to
pe
ak
ve
lo
ci
ty
(T
PV
),
du
ra
tio
n
of
ec
ce
nt
ri
c
m
us
cl
e
ac
tio
n
(D
O
E)
an
d
du
ra
tio
n
of
co
nc
en
tr
ic
co
nt
ra
ct
io
n
(D
O
C
C
)
fo
r
re
bo
un
d
be
nc
h
pr
es
se
s
at
lo
ad
s
ra
ng
in
g
fr
om
30
to
80
%
1
re
pe
tit
io
n
m
ax
im
um
.
% 1R
M
R
eb
ou
nd
be
nc
h
pr
es
s
PV
(m
·s
2
1 )
PF
(N
)
TP
V
(s
)
D
O
E
(s
)
D
O
C
C
(s
)
R
eb
ou
nd
be
nc
h
pr
es
s
th
ro
w
PV
(m
·s
2
1 )
PF
(N
)
TP
V
(s
)
D
O
E
(s
)
D
O
C
C
(s
)
30 40 50 60 70 80
1.
52
6
0.
17
1.
37
6
0.
16
1.
21
6
0.
16
0.
99
6
0.
12
0.
83
6
0.
13
0.
65
6
0.
15
49
1.
8
6
11
0.
6
59
6.
1
6
11
8.
4
69
2.
7
6
14
8.
6
78
6.
4
6
13
6.
8
87
6.
6
6
16
4.
1
90
6.
5
6
15
6.
9
0.
34
8
6
0.
10
2
0.
42
5
6
0.
12
2
0.
50
8
6
0.
10
5
0.
59
3
6
0.
12
6
0.
72
0
6
0.
14
8
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92
7
6
0.
40
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63
7
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9
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4
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80
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5
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0
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8
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48
6
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6
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13
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59
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21
6 produce greater average velocities (12.3% higher mean
across loads) and peak forces (14.1% higher mean
across loads). However, neither rebound nor release af-
forded greater load-tension (average force). Techniques
(concentric only) that maintain tension for longer du-
rations, maximize the contribution of the contractile
component and minimize the recoil contribution of the
passive elastic component, may be the most desirable
techniques for changing the strength and CSA of mus-
cle. Some literature supports such a contention because
similar gains in muscle strength and size have been
reported for concentric-only training as compared
with eccentric-only (15–17) or eccentric-concentric
training (13) or greater gains with concentric training
(19). Further justification for such an approach is that
the eccentric force implemented in an SSC appears to
be ultimately limited by concentric force production
(13). That is, as reported previously, prestretch poten-
tiates the concentric contraction by 12–18%. If such
augmentation is evident, the only manner in which
greater SSC performance may ensue is by developing
the ability of the muscle to generate greater concentric
force. Intuitively and according to the principle of
specificity, it would seem that techniques that mini-
mize the contribution of rebound and maximize con-
centric contribution should be the methods of choice
to achieve this purpose.
An interesting study, which raises questions as to
the importance of load and tension in maximal
strength development, trained the elbow flexors of the
nondominant arm using loads of 15% (10 reps), 35%
(7 reps), and 90% (2 reps) of 1RM (20). Training vol-
ume was equated by matching the total time under
tension between loads, and subjects were encouraged
to move their respective loads with maximal effort.
After 9 weeks of training, significant maximal strength
gains were recorded (6–7%), but the differences be-
tween the light (15% 1RM) and heavy (90% 1RM)
groups were nonsignificant. Similar methodologies
and findings by other researchers support the findings
of Moss et al. (8, 27). It was concluded that their results
were not in conflict with the idea that high tension
may be the stimulus for increased maximal strength
albeit high forces were of shorter duration. It may be
that load is not as importanta stimulus as initially
proposed. If the results of this study were extended to
compare equi-volume (load) training between a
strength-training stimulus (80% 1RM) and a power-
training stimulus (40% 1RM), the results in Table 3
would hypothetically eventuate.
It is obvious from the table that when training con-
trols or equates for volume, as much of the research in
this area does, the actual set kinematics and kinetics
between training protocols vary dramatically. It can be
observed from Table 3 that the power-training stimu-
lus (40% 1RM) offers similar average force and greater
time under tension, peak force, and power outputs.
Force-Velocity Analysis of Strength Training 153
Figure 2. Average velocity (m·s21) at different loads relative to 1 repetition maximum for 4 different explosive weight-train-
ing techniques.
Table 3. Hypothetical values for various kinematic and kinetic variables when equated by volume.*
Variable
2 reps at
80% 1RM
4 reps at
40% 1RM
Duration of eccentric phase (s)
Duration of concentric phase (s)
Total time under tension (s)
Average force (N)
Peak force (N)
Average power (W)
Peak power (W)
2 3 1.23 5 2.46
2 3 0.831 5 1.662
4.122
2 3 678.9 5 1,377.8
2 3 902.5 5 1,804.0
2 3 232.2 5 464.4
2 3 468.8 5 937.6
4 3 0.642 5 2.56
4 3 0.629 5 2.516
5.076
4 3 340.4 5 1,361.6
4 3 596.1 5 2,384.4
4 3 263.3 5 1,053.2
4 3 536.6 5 2,145.2
* Volume estimated from 1 repetition maximum (1 RM) of 100 kg. Therefore 2 reps at 80% 1RM 5 160 kg. For equi-volume
loading to occur at 40% 1RM, 4 repetitions must be performed. The individual values for each variable are multiplied by the
number of repetitions to calculate the total per variable per set.
Given the limitations of this example, more research
of this nature that analyses the kinematic and kinetic
characteristics of reps and sets would give better in-
sights into the changes and adaptations occurring with
the repeated application of that training stimulus. For
example, a better understanding of the findings of
Moss et al. is enabled if framed in a set kinematic or
kinetics context. Certainly this type of paradigm that
investigates set kinematics and kinetics and the effects
of such training on maximal strength and power de-
velopment warrants further investigation.
Throwing the bar produced greater average veloc-
ities than traditional techniques that held the bar, for
the lighter loading intensities of 30–60% 1RM. With
heavier loading intensities (70–80% 1RM), the ability
to release the load became compromised and the ben-
efits of throwing the load negated. Temporal analysis
of the signals revealed that peak velocities were
achieved later in the concentric action for the throw
conditions, indicating that the bar is being accelerated
over a greater portion of the concentric phase. Newton
et al. (22) found similar results, explaining that the bar
was accelerated throughout a greater range in RBPT
(96%) compared with RBP (60%), resulting in higher
end velocities. As a result of the greater duration of
concentric acceleration, a corresponding increase in
force production would be expected. This was not the
case, however, because the enhancement of bar velocity
by the throw was apparently offset by the muscle’s in-
ability to generate force at high shortening velocities
according to the force-velocity relationship of the mus-
cle.
154 Cronin, McNair, and Marshall
Unlike force, the shortening velocity of muscle may
be independent of the actual number of cross-bridges
that interact with actin filaments (9). High-intensity,
heavy-load training that increases myofilament num-
ber will have little benefit in producing changes in
contraction velocity. Rather, training that aims at in-
creasing the rate of the cross-bridge attach-detach cycle
is needed. Maximal velocity training that uses light
loads and allows projection of oneself or an object
would appear to be the best option. Light-load ballistic
training is typified by shorter contraction times, short-
er time to peak velocity, higher average and peak ve-
locities, and decreased force output. As such, this type
of training is more likely to stimulate high-velocity ad-
aptation within the muscle. It should be noted, how-
ever, that the training velocities recorded in this re-
search and encountered in the weight-training envi-
ronment (0.63–1.68 m·s21) do not simulate the actual
release velocities recorded for functional tasks. For ex-
ample, release velocities of 11.96 and 13.0 m·s21 have
been recorded for the netball chest pass and shot put,
respectively (7, 26). The importance of velocity speci-
ficity in strength training for improved functional per-
formance certainly appears to lack external validity. It
may be that the value of ballistic training is not the
actual velocity specificity of the weight-training move-
ment but rather the movement pattern specificity the
movement allows. That is, the acceleration or deceler-
ation profiles better simulate everyday and sporting
activities and, therefore, may lead to more efficient co-
ordination and activation patterns. It may be that for
functional high-velocity adaptation to occur, sport-
specific motion training needs to occur in liaison with
other resistance strength-training techniques and load-
ing patterns (complex or combination training). More
research that combines strength and conditioning and
motor control perspectives would undoubtedly result
in a better understanding of the transference of
strength and power gains to functional performance.
Practical Applications
Because the force-velocity relationship of muscle char-
acterizes the dynamic capability of muscle, the force-
velocity response of muscle to a variety of strength-
training techniques and loads was studied. Average
force output was unaffected by the technique used
across all loads. Greater force output was recorded us-
ing higher loading intensities. It was proposed that
heavy loading coupled with techniques that maintain
tension for longer durations, maximize the contribu-
tion of the contractile component, and minimize the
recoil contribution of the passive elastic component
would appear to be the most desirable for improving
force output. Implicit in such an approach would be
the use of techniques that minimize the contribution
of rebound. In this regard, concentric-only training,
super-slow training, pause training, functional iso-
metrics, and interrep rest training may be the best re-
sistance-training techniques to achieve these goals. Su-
per-slow training uses extended eccentric and concen-
tric phases to keep the muscle under constant tension.
The added advantage of slow motion is that the rate
of eccentric contraction and slow coupling times result
in greater loss of elastic energy (5), thereby minimizing
the contribution of the passive elastic elements. Pause
training ensures that the contractile element is more
forcibly worked because pauses of 4 seconds or greater
at the completion of the eccentric phase of the motion
ensure that any augmentation afforded by elastic en-
ergy is dissipated as heat (29). Functional isometrics
combines a dynamic isoinertial contraction with an
isometric contraction for a given movement and re-
sults in greater mean concentric forces and time under
tension than do traditional weightlifting techniques
(25). Interrep rest training incorporates the complete
unloading of the active musculature for a period of
time at the completion of the eccentric phase. It is
thought that the periodic blood flow during the relax-
ation between repetitions is more likely to stimulate
peripheral adaptations that result in improvements in
aerobic function (3). However, transference of strength
and power gains from this type of training to dynamic
functional performance may be compromised because
of the lack of specificity of such training to everydayand sporting activities. This problem may be mini-
mized if such training is combined with ballistic train-
ing. Ballistic training (30–60% 1RM) led to greater
movement velocities in this study. As such, this type
of training is more likely to stimulate high-velocity ad-
aptation within the muscle, especially if the training
velocities approach the actual movement velocity of
the athletic event. A further benefit of ballistic training
was the movement pattern specificity it allowed, the
acceleration-deceleration profiles similar to those en-
countered in the athletic environment. To what extent
the repeated applications or combination of these dif-
ferent techniques affect strength, power, and function-
al performance needs to be examined in the future.
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Address correspondence to Dr. John B. Cronin,
john.cronin@ait.ac.nz.