International  Journal  of
Environmental Research
and Public Health
Article
The Eﬀect of Ballistic Exercise as Pre-Activation for
100 m Sprints
Maria H. Gil 1,2, Henrique P. Neiva 1,2
, Nuno D. Garrido 2,3, Felipe J. Aidar 4,5,6,7,
Maria S. Cirilo-Sousa 8,9, Mário C. Marques 1,2 and Daniel A. Marinho 1,2,*
1
Department of Sport Sciences, University of Beira Interior, 6201-001 Covilhã, Portugal;
maria.helena.gil@hotmail.com (M.H.G.); henriquepn@gmail.com (H.P.N.);
mariomarques@mariomarques.com (M.C.M.)
2
Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, 6200-001 Covilhã,
Portugal; ndgarrido@gmail.com
3
Department of Sports, Exercise and Health Sciences, University of Trás-os-Montes e Alto Douro,
5001-801 Vila Real, Portugal
4
Department of Physical Education, Federal University of Sergipe - UFS, São Cristovão, SE 49100-000, Brazil;
fjaidar@gmail.com
5
Post Graduate Program in Master’s level in Physical Education, Federal University of Sergipe-UFS,
São Cristovão, SE 49100-000, Brazil
6
Post Graduate Program in Doctorade and Master’s level in Physiological Sciences, Federal University of
Sergipe - UFS, São Cristovão, SE 49100-000, Brazil
7
Group of Studies and Research of Performance, Sport, Health and Paralympic Sports - GEPEPS, the Federal
University of Sergipe - UFS, São Cristovão, SE 49100-000, Brazil
8
Associate Graduate Program in Physical, Department of Physical Education, Federal University of Paraíba,
João Pessoa, PB 58051-900, Brazil; helpcirilo@yahoo.com.br
9
Department of Physical Education, Regional University of Cariri, Crato, CE 63105-010, Brazil
*
Correspondence: marinho.d@gmail.com; Tel.: +35-1-275329153
Received: 23 April 2019; Accepted: 21 May 2019; Published: 24 May 2019


Abstract: The beneﬁts of warm-up in sports performance has received a special interest in the current
literature. However, there is a large gap of knowledge about the tasks to be performed, speciﬁcally
in the real competitive environment. The purpose of the study was to verify the acute eﬀects of a
warm-up including ballistic exercises in 100 m running performance. In addition, a second 100 m
trial was assessed to better understand the warm-up eﬀects in training and competition. Eleven men
(25.4 ± 6.2 years of age, 1.76 ± 0.08 m of height, 78.2 ± 8.6 kg of body mass) were submitted to three
diﬀerent protocols, in a randomized order: no warm-up (NWU), typical warm-up (WU) and WU
complemented with ballistic exercises (PAP). Biomechanical, physiological and psychophysiological
variables were assessed. Diﬀerences were found between the three conditions assessed in the ﬁrst
100 m sprint with 7.4% and 7.6% faster performances after the WU and PAP, compared to NWU.
Stride length was higher in the second part of the 100 m after PAP compared with WU. These
results highlight the positive eﬀects of warm-up for sprinting performance. The inclusion of ballistic
exercises, besides being used to improve sprint performance, can increase stride length in the ﬁnal of
the 100 m race.
Keywords: warm-up; performance; repeated-sprint; physiology; biomechanics
1. Introduction
Warm-up practices have been used to prepare the athlete for training and/or competition [1].
It is believed that a well-designed warm-up causes physiological changes and helps the athlete to
Int. J. Environ. Res. Public Health 2019, 16, 1850; doi:10.3390/ijerph16101850
www.mdpi.com/journal/ijerph
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increase the mental focus for the next task, allowing them to optimize the performance [2]. The main
eﬀects of warming up derived from increased body temperature and from the muscle movement,
both contributing to decreased joint and muscle stiﬀness, improved nerve conduction rate, eﬃcient
metabolic reactions, increased blood ﬂow to the active muscles, increased oxygen uptake and to
potentiate post-activation mechanisms [3,4].
There has been an increase in interest in the warm-up issue, evidenced by the number of recent
studies and most reporting high beneﬁts for performance in diﬀerent sports and activities [5–7].
Speciﬁcally, in running, it is now well stablished that warm-up improves sprint performance [1,6,8].
Usually, warm-up included a brief period of low intensity aerobic (e.g., light to submaximal running)
and stretching exercises, followed by speciﬁc exercises related with the following activity and/or
sport [1,9]. During this speciﬁc phase of warm-up, the coaches and the athletes have been using
several exercises for the same purpose, such as dynamic and static stretching [10], agility exercises and
ballistics [11]. The last of these, the ballistic exercises, are a recent trend of speciﬁc warm-up and are
believed to cause a post-activation potentiation phenomenon, thus enhancing the performance [12,13].
Researchers have looked at the post-activation potentiation phenomenon, suggesting that it might
improve muscle power manifestations [14,15]. This increase in force production usually happens after
a maximum or near maximal muscle stimulation [10]. Post-activation potentiation seems to augment
muscle force generating capacity as a result of the previous contractile history of the muscle cells
involved in the previous contraction [14]. There is an acute eﬀect that increases the speed of conduction
of the nerve impulse to the muscle, increases the number of recruited motor units and improves the
interaction mechanism of contractile ﬁlaments [16]. The main mechanisms responsible for this are
not totally clear, but studies attributed improvements to the increased phosphorylation of the myosin
regulatory light chain [17–19]. Post-activation potentiation seems to cause neuromuscular changes and
improves type II muscle ﬁber activity, thus favoring performance in short-term maximal eﬀorts [13].
An improvement of 3% was found in 40 m sprints after performing back squats at 85% of 1
repetition maximum (1RM) [20]. Improvements of 2% and 3% were also found in 10 and 30 m sprints
after 10 repetitions of half back squat exercise at 90% 1RM [21]. Nevertheless, Kilduﬀ et al. [22] found
that one set of three repetitions of a squat exercise at 87% 1RM did not improve 15 m swimming
performance, compared to a traditional in-water warm-up. Previous research mainly focused on high
external loads of strength exercise during warm-up and it is known that it cannot be applied in a real
competition context [13,20,23]. There is a real need for understanding the eﬀects of the post-activation
potentiation using some usual tasks that can be reproduced in a real competition venue. The ﬁrst
studies on this revealed that including depth jumping in the warm-up protocol increased both maximal
strength [24] and vertical jump [25,26]. Byrne, Kenny and O’Rourke [27] concluded that the addition of
three depth jumps resulted in a 5% improvement of 20 m running compared to a traditional warm-up.
However, little is known regarding when these ballistic exercises are used before Olympic racing
distances, such as the 100 m. Moreover, little is known about the eﬀects of using post-activation
potentiation strategies on the biomechanical variables during running. Running performance depends
on the stride parameters and, for instance, the optimal ratio between stride length (SL) and stride
frequency (SF) enable maximal sprinting velocity and eﬃciency [28]. This relationship is conditioned
by the neuromuscular regulation of movement, morphological characteristics, motor abilities and
energy substrates [29,30], all of which can be inﬂuenced by warm-up tasks [1,7,13].
Therefore, it was hypothesized that a warm-up that included ballistic exercises would improve
100 m running performance, by changing the stride parameters (SL and SF) and physiological response.
So, the primary aim of the current study was to verify the acute eﬀects of a warm-up including ballistic
exercises inducing a post-activation potentiation, easy to apply in a real competition context, in 100 m
running performance. In addition, a second 100 m trial was assessed to better understand the warm-up
eﬀects during competition and training. To the best of our knowledge, no previous investigation
has used a second repetition, and this is important to understand the neuromuscular and metabolic
responses, helping to develop optimized training strategies. Repeated eﬀorts have been used as
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determinants for success in a wide range of sports and may be associated with neuromuscular and
metabolic factors that inﬂuence performance [31,32]. The primary outcomes for our study were the 100
m running performance (time) and biomechanical variables (SL and SF). Secondary outcomes included
physiological (lactate concentration and heart rate) and psychophysiological (ratings of perceived
eﬀort) variables.
2. Materials and Methods
2.1. Participants
Eleven men aged 20–36 years (mean ± SD: 25.4 ± 6.2 years of age, 1.76 ± 0.08 m of height,
78.21 ± 8.59 kg of body mass) volunteered to participate in this study. Participants were physically
active sport science students. Each individual was asked to report any previous illness, injury or
other physical issue that would hinder their performance. Participants were included on the basis
that they were healthy, injury free, and engaged in physical activity regularly with an experience of
running and testing for the last two years, although they were not competitive sprinters. Criteria
of exclusion from the study was the evidence of any medical or orthopedic problem, a self-reported
ﬁtness classiﬁcation below moderately active, or any other self-reported issue that would endanger
their own health (assessed via questionnaire). After local ethics board approval, ensuring compliance
with the Declaration of Helsinki, the subjects were informed about the study procedures, and a written
informed consent was signed.
2.2. Design
The purpose of the present study was to evaluate the eﬀects of typical warm-up procedures (WU),
the inclusion of post-activation potentiation exercises (PAP) and no warm-up (NWU) on 100 m running
performance, analyzing biomechanical, physiological and psychophysiological variables.
Each participant completed two 100 m time-trials after each warm-up condition, in a randomized
order, separated by 48 h. The WU design was based on literature recommendations [8,32] and included
a low intensity aerobic component followed by speciﬁc running tasks. The PAP protocol included
lower body ballistic exercises according to previous suggestions [33] after completing WU. During the
NWU condition, the subjects were asked not to perform any type of action or movement prior to the
100 m sprint, remaining seated for 5 min. This design was able to test whether the inclusion of PAP
strategies during warm-ups aﬀected running performance.
2.3. Experimental Procedures
All the procedures took place at the same time of the day (8:00–12:00 a.m.) for each participant
under the same environmental conditions (~22 ◦C air temperature and ~60% of humidity) in an
athletics track facility. The participants were familiarized with the warm-up procedures 72 h before
the experiments, and they were reminded to maintain the same routines during the assessment days,
avoiding strenuous exercise, and abstaining from consuming caﬀeine 48 h before testing.
After arriving, each participant remained seated for 5 min and baseline measurements of heart
rate (HR; Vantage NV; Polar, Kempele, Finland) and blood lactate concentrations([La−]; Lactate Pro LT
1710; Arkray Inc., Kyoto, Japan) were then assessed. Each volunteer was then randomly assigned to a
warm-up protocol (Figure 1).
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Figure 1. Schematic representation of the study design and testing procedures used. HR = heart
rate; [La−] = blood lactate concentration; SF = stride frequency; SL = stride length; RPE = ratings of
perceived exertion.
2.4. Warm-Up Protocols
The warm-ups were designed based on research [1,8,32] and with the help of an experienced coach.
The main diﬀerence between the warm-ups were the inclusion of lower-body ballistic exercises to
stimulate post-activation potentiation. WU comprised 5 min of easy run (lower than 65% of estimated
maximal HR), eight exercise drills (20 m repetitions with 10 s of recovery between them), such as
rhythmic jumps from foot to foot, ankle drills, skipping drills, high-knee running. Then, these technical
exercises were followed by 2 × 40 m running at gradually increasing intensity. In the PAP condition,
the participants performed the WU followed by 2 sets of 5 depth jumps from a box of 70 cm height
(3 min recovery) as suggested by Maloney et al. [33]. Each jump was performed by stepping oﬀ a box
with one foot, landing with bent knees, then immediately jumping with maximal eﬀort. The subjects
were instructed to jump as quick and high as possible and to keep their hands on their hips to eliminate
any contribution of arm swing [9,27].
2.5. Time-Trial Performance
Once the participants ﬁnished warming-up, they remained seated for 5 min before performing the
100 m time-trials. The subjects started from a standing position with the trunk bent forward and the
lower limbs apart and slightly bent, positioned behind the starting line. After oﬃcial commands, each
participant started maximal running using a standing start with the lead-oﬀ foot placed 1 m behind the
ﬁrst timing gate. Times were measured by photocell timing gates (Brower photocells, Wireless Sprint
System, USA) placed at 0, 50, and 100 m so that the times needed to cover 0–50 m (T0–50), 50–100 m
(T50–100) and 0–100 m (T100) could be determined. After 10 min rest, the subjects performed a second
100 m sprint.
2.6. Kinematics
All the procedures were recorded by two video cameras (Casio Exilim Ex-F1, f = 30 Hz) placed
perpendicular to the running track. This enabled the acquisition of basic kinematic data such as
the number of strides performed by each subject, the average stride length (SL) and average stride
frequency (SF) calculations, between 0 and 50 m and between 50 and 100 m, using an open-source
software (Kinovea, version 0.8.15). In running, a stride is deﬁned as the time between two consecutive
speciﬁc discrete events, normally deﬁned as two consecutive foot strikes on the same foot. SL is
deﬁned as the distance traveled during a stride and SF is deﬁned as the rate of strides per min. SF was
converted to International System Units (Hz) for further analysis. Knowing the time performed and
thus the running velocity, SL was determined from the division of running velocity by SF [34,35].
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2.7. Physiological and Psychophysiological Variables
Capillary blood samples for [La−] assessment were collected from the ﬁngertips before and 5 min
after warm-ups, 3 and 6 min after each 100 m sprint to obtain the highest value ([La−]peak) [36], and
after 15 min of recovery. HR was assessed before and after each warm-up (5 min), immediately after
each time-trial (1 min) and after 15 min of recovery. Additionally, the rating of perceived exertion
(RPE) was recorded using a 10-point modiﬁed Borg scale (Borg [37], modiﬁed by Foster et al. [38]) after
warm-ups and after the time-trials.
2.8. Statistical Analysis
Standard statistical methods were used for the calculation of mean ± SD, and 95% conﬁdence
intervals for all variables. The normality of all distributions was veriﬁed using Shapiro–Wilk tests.
Data for all variables analyzed were homogeneous and normally distributed. The eﬀect of the
warm-up procedures was analyzed by an ANOVA for repeated measures, with sphericity checked
using Mauchly’s test. When the assumption of sphericity was not met, the signiﬁcance of F-ratios
was adjusted according to the Greenhouse–Geisser procedure. Bonferroni post-hoc analysis were
performed to further investigate the eﬀect of each condition. All these statistical procedures were
performed using IBM SPSS Statistics for Windows®, version 22.0 (Armonk, NY, USA: IBM Corp.) and
the level of statistical signiﬁcance was set at p ≤ 0.05. In addition, the eﬀect size was calculated to
estimate variance between conditions (partial eta squared: ηp2) and Hedges’ g (ES) for within-subjects’
comparisons using the Excel spreadsheet by Lakens [39]. ES values of 0.20, 0.60, 1.20 and 2.00 were
considered small, moderate, large and very large magnitudes, respectively [40]. For ηp2, cut-oﬀ values
were interpreted as 0.01 for small, 0.09 for moderate and 0.25 for large.
3. Results
Before warm-up, the physiological variables were not diﬀerent between conditions. Baseline
measurements of HR (70 ± 7 bpm vs. 69 ± 7 bpm vs. 70 ± 7 bpm; F = 0.35, p = 0.71, ηp2 = 0.04) and
[La−] (2.5 ± 0.6 mmol·L−1 vs. 2.5 ± 0.6 mmol·L−1 vs. 2.5 ± 0.6 mmol·L−1; F = 0.41, p = 0.67, ηp2 = 0.04)
were similar between the three conditions.
Table 1 presents a comparison between the HR and the [La−] immediately after the warm-ups. It
was possible to verify signiﬁcant diﬀerences in HR (F = 19.80, p < 0.001, ηp2 = 0.69) and [La−] (F = 35.29,
p < 0.00, ηp2 = 0.80), with higher values for either warm-ups compared with no warm-up condition.
No diﬀerences were found in perceived exertion between warm-ups performed (WU: 4.27 ± 1.27 vs.
PAP: 3.80 ± 1.40; p = 0.34, ES = 0.32).
Table 1. Mean ± SD values (95% conﬁdence interval) of physiological responses to no-warm-up (NWU),
typical warm-up (WU) and post-activation potentiation warm-up (PAP) (n = 11). p-values and eﬀect
sizes (ES) are also presented.
NWU vs. WU
NWU vs. PAP
WU vs. PAP
NWU
WU
PAP
p-Value
ES
p-Value
ES
p-Value
ES
HR
(bpm)
72 ± 6
(68, 76)
99 ± 13
(89, 108)
91 ± 9
(86, 97)
<0.001 **
2.72
<0.001 **
2.43
0.42
0.70
[La−]
(mmol·L−1)
2.5 ± 0.6
(2.0, 2.9)
4.7 ± 1.1
(3.9, 5.5)
4.4 ± 1.0
(3.7, 5.1)
<0.001 **
2.48
<0.001 **
2.27
0.63
0.27
Mean ± SD values (95% conﬁdence limits). [La−] = blood lactate concentration. HR = heart rate. ** p ≤ 0.01.
Int. J. Environ. Res. Public Health 2019, 16, 1850
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Table 2 presents the results recorded in the ﬁrst 100 m sprint after NWU, WU and PAP. Large
diﬀerences were found between the three conditions assessed (F = 12.52, p = 0.005, ηp2 = 0.58) in the
100 m sprint. The participants were 7.44% and 7.57% faster after the WU and PAP, compared to NWU,
respectively. Moreover, four of them were faster after WU and seven were faster after PAP.
Table 2. Mean ± SD values of the ﬁrst 100 m time trial, biomechanical and psychophysiological
variables assessed during experimental protocols: no-warm-up (NWU), typical warm-up (WU) and
with post-activation potentiation (PAP) (n = 11).
NWU vs. WU
NWU vs. PAP
WU vs. PAP
NWU
WU
PAP
p-Value
ES
p-Value
ES
p-Value
ES
T0–50 (s)
7.30 ± 0.68
(6.85, 7.64)
7.01 ± 0.58
(6.68, 7.34)
7.00 ± 0.62
(6.61, 7.39)
0.34
0.44
0.39
0.44
1.00
0.02
T50–100 (s)
8.69 ± 0.69
(8.20, 9.18)
7.66 ± 0.73
(7.13, 8.18)
7.66 ± 0.91
(7.01, 8.31)
0.03 *
1.39
0.04 *
1.23
1.00
0.00
T100 (s)
15.99 ± 0.96
(15.30, 16.68)
14.67 ± 1.29
(13.75, 15.60)
14.66 ± 1.52
(13.58, 15.74)
0.01 ***
1.12
0.02 *
1.03
1.00
0.01
T0–50 SF
(Hz)
1.97 ± 0.19
(1.84, 2.11)
2.08 ± 0.14
(1.97, 2.18)
2.04 ± 0.13
(1.95, 2.13)
0.12
0.64
0.55
0.42
0.15
0.28
T50–100 SF
(Hz)
1.72 ± 0.21
(1.57, 1.87)
1.89 ± 0.11
(1.81, 1.96)
1.91 ± 0.10
(1.84, 1.98)
0.05 *
1.02
0.03 **
1.17
0.77
0.18
T0–50 SL
(m)
3.51 ± 0.32
(3.28, 3.75)
3.47 ± 0.34
(3.23, 3.71)
3.54 ± 0.36
(3.3, 3.86)
0.74
0.12
1.00
0.08
0.01 **
0.19
T50–100 SL
(m)
3.40 ± 0.33
(3.16, 3.63)
3.51 ± 0.42
(3.21, 3.81)
3.47 ± 0.42
(3.17, 3.77)
0.10
0.28
0.42
0.18
0.48
0.09
HR (bpm)
148 ± 24
(131, 165)
156 ± 22
(140, 172)
162 ± 18
(149, 175)
1.00
0.33
0.43
0.64
0.84
0.29
[La−]peak
(mmol·L−1)
7.6 ± 1.8
(6.3, 8.8)
8.5 ± 1.3
(7.5, 9.4)
8.9 ± 1.5
(7.8, 10.1)
0.38
0.56
0.32
0.75
1.00
0.27
RPE
6 ± 2
(5, 7)
7 ± 1
(6, 8)
7 ± 1
(6, 7)
1.00
0.35
0.76
0.30
1.00
0.08
Mean ± SD values (95% conﬁdence limits). HR = heart rate. [La−] = blood lactate concentration. RPE = ratings of
perceived exertion. ** p ≤ 0.01 and * p ≤ 0.05.
Warm-ups assessed resulted also in large eﬀects in the SF during the ﬁrst 50 m (F = 3.81, p = 0.07,
ηp2 = 0.30) and the second 50 m (F = 9.29, p = 0.01, ηp2 = 0.51) of the time-trial. The SL showed to be
clearly diﬀerent only in the second 50 m of the time-trial (F = 4.14, p = 0.03, ηp2 = 0.32). After trial, no
signiﬁcant diﬀerences were found in [La−] values (F = 2.16, p = 0.14, ηp2 = 0.19), HR (F = 1.20, p = 0.32,
ηp2 = 0.12) and RPE values (F = 0.18, p = 0.73, ηp2 = 0.02).
In the second 100 m sprint (Table 3), no diﬀerences were found between warm-ups condition (F =
0.58, p = 0.50, ηp2 = 0.06). Nevertheless, we veriﬁed that there was a 6.12% improvement from the
ﬁrst to the second sprint of 100 m in the NWU condition, while the same did not occur in the other
conditions. The diﬀerent responses to each warm-up condition in the 100 m time trials can be easily
conﬁrmed in Figure 2.
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Table 3. Mean ± SD values of the second 100 m time-trial, biomechanical and psychophysiological
variables assessed during experimental protocols: no-warm-up (NWU), typical warm-up (WU) and
with post-activation potentiation (PAP) (n = 11).
NWU vs. WU
NWU vs. PAP
WU vs. PAP
NWU
WU
PAP
p-Value
ES
p-Value
ES
p-Value
ES
T0–50 (s)
7.16 ± 0.59
(6.73, 7.58)
7.03 ± 0.56
(6.63, 7.43)
6.97 ± 0.59
(6.55, 7.39)
0.80
0.22
0.32
0.31
1.00
0.10
T50–100 (s)
7.76 ± 0.61
(7.33, 8.20)
7.70 ± 0.82
(7.11, 8.29)
7.78 ± 0.98
(7.08, 8.48)
1.00
0.08
1.00
0.02
1.00
0.09
T100 (s)
14.92 ± 1.16
(14.09, 15.75)
14.73 ± 1.36
(13.76, 15.70)
14.75 ± 1.52
(13.67, 15.84)
1.00
0.14
1.00
0.12
1.00
0.01
T0–50 SF
(Hz)
1.98 ± 0.16
(1.87, 2.10)
2.04 ± 0.09
(1.97, 2.11)
2.02 ± 0.12
(1.94, 2.10)
0.42
0.46
0.82
0.27
1.00
0.18
T50–100 SF
(Hz)
1.88 ± 0.14
(1.77, 1.98)
1.89 ± 0.12
(1.80, 1.97)
1.86 ± 0.13
(1.77, 1.95)
1.00
0.07
1.00
0.14
1.00
0.23
T0–50 SL
(m)
3.56 ± 0.32
(3.33, 3.79)
3.51 ± 0.32
(3.28, 3.74)
3.59 ± 0.38
(3.32, 3.86)
0.74
0.15
1.00
0.08
0.18
0.22
T50–100 SL
(m)
3.47 ± 0.39
(3.19, 3.75)
3.49 ± 0.38
(3.22, 3.75)
3.52 ± 0.47
(3.18, 3.85)
1.00
0.05
1.00
0.11
1.00
0.07
HR (bpm)
164 ± 10
(157, 171)
161 ± 29
(140, 182)
172 ± 20
(158, 186)
1.00
0.15
0.25
0.51
0.63
0.43
[La−]peak
[mmol·L−1]
10.6 ± 1.6
(9.5, 11.7)
11.7 ± 1.6
(10.6, 12.8)
11.7 ± 1.9
(10.4, 13.0)
0.16
0.66
0.43
0.60
1.00
0.00
RPE
7 ± 2
(6, 8)
7 ± 1
(6, 8)
7 ± 1
(7, 8)
1.00
0.06
1.00
0.14
0.84
0.23
Mean ± SD values (95% conﬁdence limits). HR = heart rate. [La−] = blood lactate concentration. RPE = ratings of
perceived exertion.
Figure 2. Mean changes (±90% CI) veriﬁed between conditions, speciﬁcally without warm-up (NWU),
after typical warm-up (WU) and after WU complemented with ballistic exercises (PAP) in each 100
m time-trial.
No signiﬁcant diﬀerences were found in running kinematics during the second sprint, speciﬁcally
regarding the SF in the ﬁrst (F = 1.89, p = 0.18, ηp2 = 0.17) and second 50 m (F = 0.33, p = 0.72, ηp2 = 0.04),
and regarding the SL in the ﬁrst (F = 2.19, p = 0.14, ηp2 = 0.19) and second 50 m (F = 0.68, p = 0.52,
ηp2 = 0.07). No signiﬁcant diﬀerences were found in [La−] values (F = 2.83, p = 0.09, ηp2 = 0.24), HR
(F = 1.21, p = 0.32, ηp2 = 0.12) and RPE values (F = 0.18, p = 0.73, ηp2 = 0.02) after the second time trial.
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No diﬀerences were found after 15 min of recovery in the HR (NWU: 94 ± 8 bpm vs. WU: 97 ± 18
bpm vs. PAP: 96 ± 6 bpm; F = 0.17, p = 0.84, ηp2 = 0.02) and in the [La−] values (7.8 ± 1.3 mmol·L−1 vs.
7.9 ± 1.3 mmol·L−1 vs. 7.7 ± 1.0 mmol·L−1; F = 0.37, p = 0.70, ηp2 = 0.04).
4. Discussion
The main purpose of the current study was to verify the acute eﬀects of a warm-up including
ballistic exercises, easy to apply on a real competition context, in 100 m running performance. It
was intended to beneﬁt from some post-activation potentiation, and thus optimize sprint running
performance. This hypothesis was partially conﬁrmed by the increased performance veriﬁed in the ﬁrst
sprint compared with the non-existence of warm-up. Nevertheless, by including some post-activation
potentiation strategies such as the ballistic exercises, there were no additional eﬀects in performance
compared to the typical warm-up procedures. These results are in accordance with previous scientiﬁc
evidence that reported optimized sprint performances after a typical warm-up or a post-activation
potentiation warm-up (e.g., [23,41]) but failed to evidence additional improvement in performances
after the use of ballistic exercises, as expected (e.g., [42,43]). Both warm-ups resulted in higher SF in
the second part of the ﬁrst time-trial compared with no warm-up. Interestingly, SL was higher in
the second part of the 100 m after PAP compared with WU. This suggest that there are some speciﬁc
technical adaptations that occur in response to diﬀerent warm-up stimulations.
The warm-up is intended to optimize the athletes’ preparedness, by increasing temperature,
blood ﬂow and muscle and metabolic eﬃciency to produce faster responses which are determinant to
performance [1,7]. The ability of the muscle to produce force can be acutely modiﬁed by warm-up by
including some conditioning muscle contractions [22]. The post-activation potentiation elicits transient
improvements in performance and has been investigated as a strategy to include during warm-up
for increasing performance [23,41]. The common exercises related to potentiation post activation
phenomenon have used heavy-load (75–95% 1RM) resistance exercise [23]. However, ballistic exercises
can be used as alternative since these are usually related with type II motor unit recruitment [44]. In fact,
ballistic activities are more practical and feasible before competition compared to exercises requiring
high-intensity external loads. That was the main reason for the assessment of ballistic exercises during
warm-up in the current studies. Recent studies found some beneﬁts by using depth jumping during
the warm-up protocol to both maximal strength [24], sprint performance [42] and vertical jump [26,42].
However, to the best of our knowledge, no studies evaluated this warm-up strategy when applied to
oﬃcial running distances such as the 100 m race and tried to understand the biomechanical responses
during the race.
The results showed that the 100 m running performance was positively inﬂuenced by the warm-up.
All the participants performed better after either warm-ups and, despite no statistically signiﬁcant
diﬀerences found between WU and PAP (p = 1.00, ES = 0.01), seven athletes recorded their best times
after PAP. This could mean that there might be an individual response to PAP stimulation, as already
highlighted by Till and Cook [42]. These authors found no diﬀerences in 20 m running performance
by adding diﬀerent post-activation potentiation strategies to usual warm-up, such as deadlift (5
repetitions at 5 repetitions maximum), or tuck jump (5 repetitions), or isometric maximum voluntary
knee extensions (3 repetitions for 3 s) [42]. Nevertheless, others found positive eﬀects on the use of
ballistic exercises in running performance. Byrne et al. [27] veriﬁed that a brief warm-up of 5 min of
running, dynamic stretches and three vertical jumps resulted in 5% better performance in 20 m sprint
compared to the warm-up without the jumps. Accordingly, Lima et al. [45] found that 2 × 5 jumps from
a height of 0.75 m caused 2% faster 50 m sprint performance. More recently, Turner et al. [44] found
that the utilization of alternate-leg plyometric bounding provided an eﬀective strategy for acutely
improving sprint acceleration performance (10 and 20 m). Thus, it would be expected that there would
be greater diﬀerences between the warm-ups performed, since the use of ballistic exercises during
warm-up have been suggested as potentiating performance in explosive and short-term eﬀorts [14,15].
In fact, most studies looked at race distances markedly lower than that used in the current study. This
Int. J. Environ. Res. Public Health 2019, 16, 1850
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longer distance might have caused the potentiation eﬀects to disappear among other determinants of
performance [46].
Maximal running performance results from an optimal ratio between SF and SL [28]. Some
studies claimed SL to be the most inﬂuencing variable for maximal running velocity [47] while others
suggested the SF [28]. Nevertheless, it is a fact that the runners adjust the SL and the SF to run most
eﬃciently, optimizing velocity according to their own characteristics [48]. In the current study, better
sprint times after warm-up could be caused by the ability to maintain a higher SF on ﬁnal 50 m of the
100 m sprint without compromising the SL values. This situation did not occur in the NWU condition.
Our results corroborated with previous research that suggested that there is a biomechanical adaptation
in response to diﬀerent warm-up procedures [2,49].
Interestingly, the running kinematics showed to be diﬀerent in response to WU or PAP. In the PAP
condition, the participants showed greater SL in the beginning of the race, contrarily to the SF that
showed to be lower, compared with the WU condition. The PAP seemed to acutely stimulate the force
required for an increased SL and perhaps improving the eﬃciency of the movement, that remained
higher in the beginning of the second sprint. The eﬀects of warm-up on acute motor learning and
on sensorimotor responses could lead to diﬀerent biomechanical movement patterns after diﬀerent
warm-ups [49]. Our WU ended with some speciﬁc running exercises and the PAP ended with jumps.
It is a fact that the running exercises and running acceleration exercises could have prepared the
participants to perform higher SF, while the jumps generated a greater capacity to exert muscular
power, hence more eﬀective force in less time and thereupon greater SL. So, this diﬀerent biomechanical
running adaptation might be partially explained by the speciﬁcity of the preload stimulus, since the
vertical jump is biomechanically diﬀerent from horizontal running.
The physiological variables showed an increased response to warm-up, with higher HR and [La−]
values after warm-up, and within the range of values that some authors suggested to be adequate
for a proper warm-up [49,50]. This perhaps explain the better response in the ﬁrst sprint after either
warm-up procedures. Nevertheless, those diﬀerences disappeared after the ﬁrst time-trial, which may
be seen as a speciﬁc warm-up stimulus that in some way places the participant at a similar preparation
level. The ﬁrst sprint enhanced the neuromotor excitability that resulted in performance optimization
in a second 100 m sprint [6,31]. The non-existence of diﬀerences between HR and [La−] values might
suggest that PAP stimulation by the ballistic exercises used were not enough to induce physiological
stress. Once again, this could be caused by the lack of speciﬁcity of the jumps and/or an insuﬃcient
load to stimulate some higher responses in PAP. We should be aware of a possible individualized eﬀect
of PAP stimulation, that was already documented before [15,51]. Moreover, we could speculate that
the interval after PAP was not adequate for each runner [52,53]. It is known that the PAP eﬀect may
last for 5 to 10 min [53] and within this period, there are diﬀerent moments of maximal potentiation
for each individual [23]. However, our results were reliable and enlightening about the use of both
warm-up procedures and that PAP could be used as an alternative to traditional warm-up.
Some limitations, however, should be addressed. In fact, our results could not entirely be
extrapolated to performance of higher skilled sprints during oﬃcial events since the participants were
not sprint specialists/athletes and it is known that post-activation potentiation could be inﬂuenced by
training levels [19]. Also, further studies should include a larger number of participants and include
females to clarify some of the analyzed ﬁndings. However, we took several steps to strengthen our
statistical analysis as described in the statistical section. Future research should investigate diﬀerent
post-activation potentiation strategies (e.g., combining diﬀerent jumps or short-term sprints) and
diﬀerent recovery times between the warm-up and the race. Moreover, other evaluation methods
could be used to complement our measures and to deepen our ﬁndings, such as body temperature
and other biomechanical variables (e.g., contact time and horizonal forces production). Considering
our limitations, readers should interpret our results with discernment. Even so, the current ﬁndings
are still relevant for coaches and researchers for increased knowledge on warm-up and the eﬀects
on performance.
Int. J. Environ. Res. Public Health 2019, 16, 1850
10 of 12
5. Conclusions
The results suggested that 100 m running performance was positively inﬂuenced by warm-up
procedures, evidenced by the best results after the WU and the PAP compared to the NWU condition.
Moreover, our results suggested that 100 m is equally optimized after WU or PAP, but with diﬀerent
running kinematics. Thus, in support of our original hypotheses, we have demonstrated that warming
up beneﬁts the 100 m running performance and that ballistic exercises, easy to perform by using body
mass, can be used as an alternative to typical warm-up procedures.
Some practical applications can be drawn. It seems clear that 100 m sprinters should warm-up
for better competitive and training performances. When no warm-up is possible, a single 100 m
trial can be enough to stimulate and prepare the athlete for that unusual situation. Yet, it is usually
possible to warm-up before the race or training session and in this case, the PAP could be included in
the warm-up to potentiate some individual beneﬁts. Moreover, if the individual 100 m race strategy
depends on having a higher SF, a typical warm-up should be used, whereas if higher SL is needed,
the warm-up including ballistic exercises should be used. The current results alert coaches and
researchers the need for tailored and customized warm-up designs and speciﬁcally post-activation
potentiation strategies during warm-up. The current study took a novel approach to warm-up research
by examining the eﬀects of including post-activation potentiation exercises (i.e., ballistic exercises) in
running performance and in running stride kinematics.
Author Contributions: Conceptualization, H.P.N., D.A.M. and M.C.M.; methodology, H.P.N., D.A.M.; software,
M.H.G.; validation, H.P.N., D.A.M. and M.C.M.; formal analysis, H.P.N. and D.A.M.; investigation, M.H.G.,
D.A.M., N.D.G., M.S.C.-S. and F.J.A.; resources, N.D.G., F.J.A. and M.S.C.-S.; data curation, M.H.G. and H.P.N.;
writing—original draft preparation, H.P.N. and M.H.G.; writing—review and editing, H.P.N., N.D.G., F.J.A. and
D.A.M.; visualization, H.P.N., D.A.M. and M.C.M.; supervision, M.C.M. and D.A.M.
Funding: This research received no external funding.
Acknowledgments:
This work was supported by national funding through the Portuguese Foundation
for Science and Technology,
I.P.,
under project UID/DTP/04045/2019 and the European Fund for
Regional Development (FEDER) allocated by European Union through the COMPETE 2020 Programme
(POCI-01-0145-FEDER-006969)–competitiveness and internationalization (POCI).
Conﬂicts of Interest: The authors declare no conﬂict of interest.
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The Effect of Ballistic Exercise as Pre-Activation for 100 m Sprints.
Gil, Maria H,Neiva, Henrique P,Garrido, Nuno D,Aidar, Felipe J,Cirilo-Sousa, Maria S,Marques, Mário C,Marinho, Daniel A