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Reproducibility and Repeatability of Five Different Technologies for Bar
Velocity Measurement in Resistance Training
JAVIER COUREL-IBA
´N
˜EZ,
1
ALEJANDRO MARTI
´NEZ-CAVA,
1
RICARDO MORA
´N-NAVARRO,
1
PABLO ESCRIBANO-PEN
˜AS,
1
JAVIER CHAVARREN-CABRERO,
2
JUAN JOSE
´GONZA
´LEZ-BADILLO,
3
and JESU
´SG. PALLARE
´S
1
1
Human Performance and Sports Science Laboratory, Faculty of Sport Sciences, University of Murcia, C/ Argentina s/n,
Santiago de la Ribera, Murcia, Spain;
2
Department of Physical Education, University of Las Palmas de Gran Canaria, Las
Palmas de Gran Canaria, Spain; and
3
Faculty of Sport, Pablo de Olavide University, Seville, Spain
(Received 19 January 2019; accepted 5 April 2019)
Associate Editor Stefan M. Duma oversaw the review of this article.
Abstract—This study aimed to analyze the agreement
between five bar velocity monitoring devices, currently used
in resistance training, to determine the most reliable device
based on reproducibility (between-device agreement for a
given trial) and repeatability (between-trial variation for each
device). Seventeen resistance-trained men performed dupli-
cate trials against seven increasing loads (20-30-40-50-60-70-
80 kg) while obtaining mean, mean propulsive and peak
velocity outcomes in the bench press, full squat and prone
bench pull exercises. Measurements were simultaneously
registered by two linear velocity transducers (LVT), two
linear position transducers (LPT), two optoelectronic cam-
era-based systems (OEC), two smartphone video-based
systems (VBS) and one accelerometer (ACC). A comprehen-
sive set of statistics for assessing reliability was used.
Magnitude of errors was reported both in absolute (m s
21
)
and relative terms (%1RM), and included the smallest
detectable change (SDC) and maximum errors (MaxError).
LVT was the most reliable and sensitive device (SDC 0.02–
0.06 m s
21
, MaxError 3.4–7.1% 1RM) and the preferred
reference to compare with other technologies. OEC and LPT
were the second-best alternatives (SDC 0.06–0.11 m s
21
),
always considering the particular margins of error for each
exercise and velocity outcome. ACC and VBS are not
recommended given their substantial errors and uncertainty
of the measurements (SDC >0.13 m s
21
).
Keywords—Standard error of measurement, Velocity-based
resistance training, Exercise testing, Monitoring, Strength
performance, Validity.
INTRODUCTION
Considerable research attention has been paid to
monitoring movement velocity during resistance
training in recent years.
14,15,26,30
Velocity-based resis-
tance training (VBRT) has been proposed as an
effective method to better characterize the resistance
training stimulus and, specifically, to more precisely
gauge the actual effort or intensity at which athletes
train. VBRT requires the use of particular technologies
to monitor bar velocity during training, and it has
multiple practical applications.
15,25,28,30–33
VBRT has
been found to be a robust, non-invasive and highly
sensitive method to estimate key performance indica-
tors, such as the relative loading intensity, maximum
strength (one-repetition maximum, 1RM) and the level
of effort and neuromuscular fatigue incurred during a
training set.
15,22,25,28,31,32
These practical applications
are however dependent on the actual degree of relia-
bility exhibited by the different existing technologies
and particular devices currently used for measuring bar
velocity. It has been shown that small changes in the
velocity developed against some reference workloads
are accompanied by critical improvements in the neu-
romuscular and functional performance of well-trained
athletes. For instance, an increment in mean concentric
velocity of just 0.07 to 0.10 m s
21
is associated with
improvements of ~5% 1RM strength in main resis-
tance exercises such as the bench press (BP), full back
squat (SQ) and prone bench pull (PBP).
15,22,31,32
Thus,
in order to successfully implement a VBRT interven-
tion, it is imperative to use sufficiently accurate and
reliable technologies for measuring bar velocity.
16
Address correspondence to Jesu´ s G. Pallare
´s, Human Perfor-
mance and Sports Science Laboratory, Faculty of Sport Sciences,
University of Murcia, C/ Argentina s/n, Santiago de la Ribera,
Murcia, Spain. Electronic mail: jgpallares@um.es
Annals of Biomedical Engineering (2019)
https://doi.org/10.1007/s10439-019-02265-6
BIOMEDICAL
ENGINEERING
SOCIETY
2019 Biomedical Engineering Society