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Acute and longitudinal effects of weighted vest training on sprint-running performance: a systematic review

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This systematic review aimed to quantify the acute and longitudinal effects that occur with weighted vests during sprint-running. PubMed, SPORTDiscus, and Web of Science were searched using the Boolean phrases (vest OR trunk) AND (sprint*) AND (resist* OR weight OR load*). From 170 articles retrieved, 11 studies (6 acute, 5 longitudinal) met the inclusion criteria. Vest loads (5–40% body mass) were found to significantly increase acute over-ground times (10–50 m 4.1–16.9%, effect sizes [ES] = 0.93–3.11) through significantly decreased velocity (−2.2% to −17.3%, ES = −0.41 to −3.19), horizontal force (−5.9% to −22.1%, ES = −0.85 to −3.30), maximal power (−4.3% to −35.6%, ES = −0.32 to −3.44), and flight times (−8.3% to −14.6%, ES = −0.88 to −1.03), while increasing contact times (14.7–19.6%, ES = 1.80–3.17). Treadmill sprints were less effected until loads >11% body mass were used. Improvements in velocity (1.2–1.3%, ES = 0.24–0.37) and times (10–50 m 1.2–9.4%, ES = 0.25–3.30) were found in longitudinal studies (5.6–18.9% body mass, 3–7 weeks). Future studies should focus on determining the optimum load and volume to clearly establish the training benefits of this form of resisted sprinting.
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Sports Biomechanics
ISSN: 1476-3141 (Print) 1752-6116 (Online) Journal homepage: https://www.tandfonline.com/loi/rspb20
Acute and longitudinal effects of weighted
vest training on sprint-running performance: a
systematic review
Paul Macadam, John B. Cronin & Erin H. Feser
To cite this article: Paul Macadam, John B. Cronin & Erin H. Feser (2019): Acute and longitudinal
effects of weighted vest training on sprint-running performance: a systematic review, Sports
Biomechanics, DOI: 10.1080/14763141.2019.1607542
To link to this article: https://doi.org/10.1080/14763141.2019.1607542
Published online: 09 May 2019.
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Acute and longitudinal eects of weighted vest training on
sprint-running performance: a systematic review
Paul Macadam
a
, John B. Cronin
a
and Erin H. Feser
a,b
a
Sports Performance Research Institute New Zealand (SPRINZ) at AUT Millennium, Auckland University of
Technology, Auckland, New Zealand;
b
Exercise Science and Health Promotion, Arizona State University,
Phoenix, USA
ABSTRACT
This systematic review aimed to quantify the acute and longitudi-
nal eects that occur with weighted vests during sprint-running.
PubMed, SPORTDiscus, and Web of Science were searched using
the Boolean phrases (vest OR trunk) AND (sprint*) AND (resist* OR
weight OR load*). From 170 articles retrieved, 11 studies (6 acute, 5
longitudinal) met the inclusion criteria. Vest loads (540% body
mass) were found to signicantly increase acute over-ground
times (1050 m 4.116.9%, eect sizes [ES] = 0.933.11) through
signicantly decreased velocity (2.2% to 17.3%, ES = 0.41 to
3.19), horizontal force (5.9% to 22.1%, ES = 0.85 to 3.30),
maximal power (4.3% to 35.6%, ES = 0.32 to 3.44), and ight
times (8.3% to 14.6%, ES = 0.88 to 1.03), while increasing
contact times (14.719.6%, ES = 1.803.17). Treadmill sprints were
less eected until loads >11% body mass were used.
Improvements in velocity (1.21.3%, ES = 0.240.37) and times
(1050 m 1.29.4%, ES = 0.253.30) were found in longitudinal
studies (5.618.9% body mass, 37 weeks). Future studies should
focus on determining the optimum load and volume to clearly
establish the training benets of this form of resisted sprinting.
ARTICLE HISTORY
Received 17 December 2018
Accepted 9 April 2019
KEYWORDS
Wearable resistance; resisted
sprints; kinematics; kinetics;
specicity
Introduction
Possessing sprint-running ability is considered a vital prerequisite for athletic success in
a wide array of sports activities (Murphy, Lockie, & Coutts, 2003). To improve sprint-
running performance an athlete generally focuses on two aspects of training: the rst
aims to improve the magnitude and rate of eective force and power output; and,
the second aims to improve the technical eciency of the sprinting action (Cissik,
2004). Various forms of acyclic and cyclic resisted strength training are commonly used
to increase force and power output (Behrens & Simonson, 2011; Rumpf, Lockie,
Cronin, & Jalilvand, 2016; Tufano & Amonette, 2018), while sprint drills in addition
to sprint-running itself, are often used for technique emphasis (Cissik, 2004). An
alternative method that blends both training approaches (resistance + technique) is
the use of additional load being added to the athlete during participation in sprint drills
via a weighted vest (Cronin & Hansen, 2006). Weighted vests are a form of wearable
CONTACT Paul Macadam paul.macadam@aut.ac.nz
SPORTS BIOMECHANICS
https://doi.org/10.1080/14763141.2019.1607542
© 2019 Informa UK Limited, trading as Taylor & Francis Group
resistance that enables an overload to be evenly distributed near an individuals centre
of mass, potentially increasing the ability to produce ground reaction forces and power
production during sprint-running (Macadam, Cronin, & Simperingham, 2017).
This form of resisted sprint training aligns with the principles of specicity of
training and the principles of individualisation and progressive overload (Faccioni,
1994; Macadam et al., 2017). Resisted sprint training is designed to increase neural
activation and strength of the lower limbs, thus increasing sprint velocity, without
unduly aecting the sprinting technique (Cissik, 2004; Faccioni, 1994). As the addi-
tional external mass is added around the torso, there may be less direct disruption to
joint and step kinematics from the limbs. Furthermore, unlike other forms of resisted
sprinting, weighted vests enable athletes to perform other motor actions such as jumps,
bounds and change of direction. Previously researchers have shown that horizontal
forces were higher during the acceleration phase, and vertical forces gradually increased
with increases in velocity during the maximum-velocity phase (Rabita et al., 2015).
Therefore, weighted vest training may be appropriate to specically target reactive
strength development for maximum velocity sprinting, while the horizontal component
of leg drive can be overloaded through sleds, parachutes or ropes (Cronin & Hansen,
2006; Rey, Padrón-Cabo, & Fernández-Penedo, 2017; Young, Benton, & Pryor, 2001).
Given that force is the product of mass and acceleration, weighted vest sprint training
may result in high forces due to the high accelerations even though when the mass is
relatively light. These high accelerative forces performed in a movement specic con-
text, provide an ideal form of coordination training that may optimise training adapta-
tion and crossover to sporting performance (Hrysomallis, 2012). Given the purported
benets of weighted vest training, the purpose of this review was to quantify the acute
and longitudinal eects that occur with weighted vests during sprint-running. Of
particular interest was to: 1) identify the mechanistic determinants of changes that
occur in sprinting with weighted vests; 2) determine whether vest loading enabled
improvement in sprint speed and, 3) detail critical loading parameters for these
changes. Such an approach will provide practitioners with a better understanding of
the eects of vest loading and how to best program for speed changes using such
resisted overload. We hypothesised that acute sprint times would be increased (i.e.,
slower) with weighted vest sprint-running, and that longitudinal sprint training with
a weighted vest would improve sprint performance times.
Methods
The review was conducted in accordance with PRISMA (Preferred Reporting Items for
Systematic Reviews and Meta-analyses) statement guidelines (Moher, Liberati, Tetzla,
& Altman, 2009). A systematic search of the research literature was undertaken for
acute (cross-sectional) and longitudinal studies assessing the eects of weighted vests on
sprint-running performance from international peer-reviewed journals. Studies were
found by searching PubMed, SPORTDiscus, and Web of Science electronic databases
from inception to November 2018. The following Boolean phrases were used for the
searches (vest OR trunk) AND (sprint*) AND (resist* OR weight OR load*). Additional
studies were also found by reviewing the reference lists from retrieved studies.
2P. MACADAM ET AL.
Inclusion and exclusion criteria
Studies with injury-free participants of any age, sex or activity level were included. No
restrictions were imposed on publication date or publication status. Studies were
limited to the English language. Studies incorporating a direct assessment of acute
performance changes during sprint-running that occurred when the weighted vest was
being worn were included. Post-activation potentiation (PAP) studies, where changes
are only assessed after the load was removed, were excluded. Studies that used other
forms of resistance, such as sled towing, or attached the resistance via alternative
methods to a vest, as in limb loads or belts, were also excluded.
Study selection
One reviewer (PM) searched the databases and selected studies. Two other reviewers
were available to assist with study eligibility. No disagreements about the appropriate-
ness of an article were encountered. A search of electronic databases and a scan of
article reference lists revealed 170 relevant studies (Figure 1). After applying the
inclusion and exclusion criteria 11 studies (six acute studies and ve longitudinal
studies) were retained for further analysis.
Records identified through electronic database searching
(n =164)
PubMed 45
SPORTDiscus 55
Web of Science 64
Additional records identified through hand searches of reference lists
and online journal
(n = 6)
Records screened for relevance on title
(n = 102)
Records screened for relevance on abstract
(n = 60)
Full-text articles screened for eligibility
(n = 16)
Studies included in qualitative synthesis
(n = 11
[
6 acute, 5 longitudinal])
Duplicate removal
(n = 70 records excluded)
Full-text articles excluded (n = 5):
5 load not attached via vest
Title selection
(n = 42 records excluded)
Abstract selection
(n = 44 records excluded)
Figure 1. Flow chart of article selection through the dierent phases of the systematic review.
SPORTS BIOMECHANICS 3
Methodological quality score
Methodological quality was assessed using the quality index of Downs and Black (1998)
modied version (Moens et al., 2018). A value of 0 or 1 was assigned to the dierent
subcategories of the following items: reporting, external validity, and internal validity.
A total score < 10/17 was considered to be low quality, while scores 10/17 were
presumed to be high quality (Moens et al., 2018).
Study analyses
Studies that reported Cohenseect size (ES) were described as trivial (<0.2), small
(<0.210.5), moderate (0.510.79) and large (>0.8) (Cohen, 1988). Where ES was not
provided, it was determined by calculating the mean dierence between groups, and then
dividing the result by the pooled standard deviation (Cohen, 1988). ES was unable to be
calculated for sprint times, step length and step frequency from Cronin, Hansen,
Kawamori, and McNair (2008) as either the mean or standard deviation were not provided
in these variables.
Results
Methodological quality score
Quality assessment scores of the 11 articles included ranged from 10 to 14, with an
average score of 11.6 out of 17, indicating a high methodological quality for the studies
reviewed (Table 1).
Study characteristics
There was a total of 113 participants (109 male, four female) from six acute studies and
41 males from ve longitudinal studies (Table 1). Participants that were included in the
analyses were characterised as either healthy sedentary, recreationally active or compe-
titive athletes from various sporting backgrounds, as described by the authors of the
reviewed articles. To allow comparison between studies, absolute load data were con-
verted to ratio data represented as a percentage of body mass (%BM). When scaled to
BM, the vest loading ranged from 5% to 40% BM. The eects of weighted vests on
sprint-running performance are summarised through six acute (Table 2) and ve
longitudinal studies (Table 3).
Acute eects of weighted vests on sprint-running
Six studies reported the acute eects of weighted vests on sprint-running performance,
kinematics and kinetics (Table 2). The vest loads used ranged from 5% to 40% BM with
over ground sprints being performed over 30 m to 50 m, and treadmill sprints being
completed over a 6-s period. Four studies assessed the eects of vest loading during
over ground sprint-running (Carlos-Vivas et al., 2018a; Carlos-Vivas, Marín-Cascales,
Freitas, Perez-Gomez, & Alcaraz, 2018b; Cronin et al., 2008; Konstantinos et al., 2014).
From the lightest loading of 5% BM, no signicant changes in kinematics or kinetics
4P. MACADAM ET AL.
were found, while sprint times were not reported with this loading magnitude (Carlos-
Vivas et al., 2018a). Vest loading of 8% BM resulted in signicantly increased split times
(i.e., sprints were slower, 4.15.1%, ES = 0.931.54) at all distances between 10 and
50 m (Konstantinos et al., 2014). Two studies used 10% BM (Carlos-Vivas et al., 2018a,
2018b) and reported decreases in Vmax (4.3% to 4.7%, ES = 1.03 to 1.05) and
Pmax (2.0% to 10.8%, ES = 0.06 to 0.99), though only signicant decreases were
Table 1. Study characteristics of all studies reviewed (n = 11).
Study
Participants (gender, age,
height, mass)
Weighted vest load
(% body mass) Sprint distance
Study
duration
Quality
score
Cronin et al.
(2008)
16 males, 4 females
(19.9 ± 2.2 years, 176 ±
8 cm, 76.5 ± 10.7 kg)
Competitive athletes from
mixed sports
15, 20 30 m Acute 10
Clark et al. (2010) 6 males
(19.7 ± 0.1 years, 182 ±
8 cm, 79.1 ± 5.3 kg)
NCAA Division 3 lacrosse
players
18.5 55 m
(measurement between
18.3 m to 54.9 m)
7 weeks 13
Rantalainen et al.
(2012)
8 males
(32.2 ± 6.4 years, 178 ±
5 cm, 81.8 ± 8 kg)
Sedentary participants
5.6 10 m 3 weeks 14
Cross et al. (2014) 13 males
(22.9 ± 3.3 years; 179 ±
6 cm, 82.5 ± 8.4 kg)
Sport active university level
athletes
10.9, 21.8 6 s on a non-motorised
force treadmill
Acute 10
Konstantinos et al.
(2014)
24 males,
(1823 years, 178 ± 5 cm,
74.2 ± 8.9 kg)
Sport science students
8, 15, 20 50 m Acute 11
Simperingham
and Cronin
(2014)
8 males
(29.2 ± 3.8 years, 177.1 ±
7.5 cm, 81.8 ± 9.7 kg)
Athletic sprint-based
athletes
5 6 s on a non-motorised
force treadmill
Acute 10
Barr et al. (2015) 8 males,
(22.4 ± 2.7 years 182 ±
6 cm, 95.3 ± 7.1 kg)
National rugby players
12 40 m 8 days 11
Scudamore et al.
(2016)
9 males
(21 ± 2 years, 181 ± 1 cm,
91.1 ± 4.4 kg)
Fitness active participants
Week 111.2 ± 0.6
Week 213.2 ± 0.7
Week 316.1 ± 0.4
36.6 m 3 weeks 14
Rey et al. (2017) 10 males
(23.6 ± 2.7 years, 178.5 ±
4.9 cm, 72.9 ± 5.2 kg)
Amateur soccer players
18.9 ± 2.1 30 m 6 weeks 13
Carlos-Vivas et al.
(2018a)
25 males
(1825 years, 179.5 ±
5.0 cm, 72.2 ± 6.7 kg)
Semi-professional soccer
players
5, 10, 15 30 m Acute 11
Carlos-Vivas et al.
(2018b)
23 males
(20.8 ± 1.5 years, 180.0 ±
6.0 cm, 75.3 ± 7.3 kg)
Semi-professional soccer
players
10, 20, 30, 40 30 m Acute 11
SPORTS BIOMECHANICS 5
Table 2. Acute eects of weighted vests on sprint-running performance, kinematics and kinetics in order of % loading (n = 6).
Study
Load %
body mass Sprint distance Sprint times Kinematics Kinetics
Simperingham and
Cronin (2014)
5 6 s non-motorised force
treadmill
5m0.6% (ES 0.06)
10 m 0.8% (ES 0.09)
20 m 0.0% (ES 0.00)
25 m 0.4% (ES 0.02)
Peak velocity 1.2% MVP (ES 0.15)
CT 3.8%* AP (ES 0.58), 4.7 %* MVP (ES 0.58)
FT 15%* AP (ES 0.44), 7.9% MVP (ES 0.30)
SL 0.0% AP (ES 0.00), 2.5% MVP (ES 0.23)
SF 0.7% AP (ES 0.12), 3.8% MVP (ES 0.61)
Relative peak VGRF 5.4%* AP (ES
0.58), 6.4%* MVP (ES 0.53)
Relative mean VGRF 3.8%* AP (ES
0.55) 4.0%* MVP (ES 0.50)
HGRF 1.0% AP (ES 0.10), 2.7% MVP
(ES 0.22)
PPO 1.4% AP (ES 0.07), 4.3% MVP
(ES 0.25)
Carlos-Vivas et al.
(2018a)
5 30 m Vmax 2.2% (ES 0.41) Pmax 4.3% (ES 0.32)
Konstantinos et al.
(2014)
850m
(from a ying start)
10 m 4.1%* (ES 0.93)
20 m 4.7%* (ES 1.54)
30 m 4.6%* (ES 1.37)
40 m 5.1%* (ES 1.51)
50 m 4.6%* (ES 1.40)
Carlos-Vivas et al.
(2018a)
10 30 m Vmax 4.3% (ES 0.81) Pmax 2.0% (ES 0.06)
Carlos-Vivas et al.
(2018b)
10 30 m 30 m 4.3% ** (ES 0.99) Vmax 4.7% ** (ES 1.05)
Vo 5.2% ** (ES 1.03)
Fo 5.9% ** (ES 0.85)
Pmax 10.8% ** (0.99)
RFmax 4.6%** (ES 0.93)
DRF 0.1% (ES 0.04)
Cross et al. (2014) 10.9 6 s non-motorised force
treadmill
Peak velocity 3.6% * (ES 0.38)
CT 4.1% AP (ES 0.38), 5.6%* MVP (ES 0.98)
FT 20% AP (ES 0.64) 17.4% MVP* (ES 0.89)
SL 4.4%* MVP (ES 0.33)
SF 0.8% MVP (ES 0.10)
Peak VGRF 4.1% AP (ES 0.34), 3.1%
MVP (ES 0.21)
Mean VGRF 3.4% AP (ES 0.34), 3.4% MVP
(ES 0.29)
HGRF 6.1% AP (ES 0.31), 0.8% MVP
(ES 0.02)
PPO 0.0% AP (ES 0.00), 3.7% MVP (ES
0.10)
Cronin et al. (2008) 15 30 m 10 m 7.5%*
30 m 10.0%*
CT 14.315.3%* (ES 1.802.10)
FT 8.3% to 9.8%* (ES 0.63 to 0.78)
SF 2.76.1%*
SL (signicantly decreased % unknown)
Konstantinos et al.
(2014)
15 50 m
(from a ying start)
10 m 6.9%* (ES 1.6)
20 m 7.4%* (ES 2.4)
30 m 6.9%* (ES 2.0)
40 m 7.5%* (ES 2.2)
50 m 7.3%* (ES 1.9)
(Continued)
6P. MACADAM ET AL.
Table 2. (Continued).
Study
Load %
body mass Sprint distance Sprint times Kinematics Kinetics
Carlos-Vivas et al.
(2018a)
15 30 m Vmax 7.3% (ES 1.26) Pmax 4.6% (ES0.17)
Cronin et al. (2008) 20 30 m 10m 9.3%*
30 m 11.7%*
CT 14.719.6%* (ES 2.003.17)
FT 12.0% to 14.6%* (ES 0.88 to 1.03)
SF 2.76.1%*
SL (signicantly decreased % unknown)
Konstantinos et al.
(2014)
20 50 m
(from a ying start)
10 m 9.9%, (ES 2.4)
20 m 9.3%, (ES 3.5)
30 m 9.2%, (ES 2.8)
40 m 9.9%, (ES 2.8)
50 m 8.2%, (ES 2.5)
Carlos-Vivas et al.
(2018b)
20 30 m 30 m 8.0%** (ES 1.89) Vmax 8.4%** (ES 1.94)
Vo 9.2%** (ES 1.97)
Fo 11.2%** (ES 1.73)
Pmax 19.4%** (ES 1.93)
RFmax 8.3%** (ES 1.85)
DRF 0.7% (ES 0.18)
Cross et al. (2014) 21.8 6 s on a non-motorised
force treadmill
Peak velocity 5.7 %* (ES 0.61)
CT 1.4% AP (ES 0.18), 9.2%* MVP (ES 1.67)
FT 26.7% AP* (ES 1.45), 18.9% MVP* (ES 1.06)
SL 4.4%* MVP (ES 0.34)
SF 1.5% MVP (ES 0.20)
Peak VGRF 3.7% AP (ES 0.19), 8.2%* MVP
(ES 0.70)
Mean VGRF 10.6%* AP (ES 1.32), 11.1%*
MVP (ES 1.16)
HGRF 6.3% AP (ES-0.30), 6.3% MVP
(ES 0.16)
PPO 7.9% AP (ES 0.27), 14.3%* MVP (ES
0.47)
Carlos-Vivas et al.
(2018b)
30 30 m 30 m 11.8%** (ES 2.52) Vmax 11.7%** (ES 2.51)
Vo 12.6%** (ES 2.52)
Fo 16.7%** (ES 2.53)
Pmax 27.3%** (ES 2.64)
RFmax 12.5%** (ES 2.61)
DRF 2.5%* (ES 0.75)
Carlos-Vivas et al.
(2018b)
40 30 m 30 m 16.9%** (ES 3.11) Vmax 16.1%** (ES 3.19)
Vo 17.3%** (ES 3.19)
Fo 22.1%** (ES 3.30)
Pmax 35.6%** (ES 3.44)
RFmax 17.1%** (ES 3.39)
DRF 3.1%* (ES 0.81)
* signicant dierences p < 0.05, ** signicant dierences p < 0.001,
AP = acceleration phase, CT = contact time, DRF = decrease in ratio of forces, as a percentage, ES = eect size, FT = ight time, Fo = theoretical maximum horizontal force in N/
kg, MVP = maximum velocity phase, PPO = peak power output in W, Pmax = maximum horizontal power output in W/kg, RFmax = maximum ratio of forces, as a percentage,
SF = step frequency, SL = step length, VGRF = vertical ground reaction force, Vmax = maximum velocity in m/s, Vo = theoretical maximum velocity in m/s
SPORTS BIOMECHANICS 7
Table 3. Longitudinal eects of weighted vests on sprint-running performance and kinematics in order of % loading (n = 5).
Study
Load %
body
mass Sprint distance Training period Sprint times Kinematics
Rantalainen
et al.
(2012)
5.6 10 m
(from a ying
start)
3 weeks, 6 training sessions
Vest worn all day excluding sport activates on 3 days
a week
Velocity 1.3% (7.33 to 7.42 m/s, ES 0.37)
Scudamore
et al.
(2016)
11.616.1 36.6 m 3 weeks, 9 training sessions
Vests worn all day for at least 8 hours a day and at
least 4 days a week (vest worn an average 34
hours a week)
36.6 m 1.5%* (4.69 to 4.58 s, ES 1.8)
Barr et al.
(2015)
12 40 m 8 days, 10 training sessions
Vest worn all day when standing and walking.
Removed for rugby training and gym exercises,
though worn when resting between exercises.
10 m 0.0% (1.76 to 1.76 s, ES 0.0)
3040 m 0.0% (1.12 to 1.12 s, ES 0.0)
40 m 0.0% (5.33 to 5.33 s, ES 0.17)
CT 0.0% AP (ES 0.18), 8.9 %* MVP (ES 0.09)
SL 0.8% AP (ES 0.07), 2.5% MVP (ES 0.28)
FT 0.0% AP (ES 0.25), 8.4%, MVP ES 0.4)
Clark et al.
(2010)
18.5 55 m
(measurement
18.3 to
54.9 m)
7 weeks, 13 training sessions
Vest worn during 2 × 60 min sessions a week of
periodised sprint training
18.3 to 54.9 m 1.2% (4.41 to 4.36 s, ES
0.25)
Velocity 1.2% (ES 0.24)
StL 2.2%, (ES 0.37)
StF 3.4%, (ES 0.78)
CT 1.5%, (ES 0.25)
FT 5.4%, (ES 1.0)
Rey et al.
(2017)
18.9 30 m 6 weeks, 12 training sessions
Vest worn during 2 sessions a week of periodised
sprint training
10 m 9.4%**, (1.78 to 1.61 s, ES 1.77)
30 m 6.1%**, (4.34 to 4.08 s, ES 3.30)
* signicant dierences p < 0.05, ** signicant dierences p < 0.001,
AP = acceleration phase, CT = contact time, ES = eect size, FT = ight time, MVP = maximum velocity phase, SF = step frequency, SL = step length, StF = stride frequency, StL =
stride length
8P. MACADAM ET AL.
found by Carlos-Vivas et al. (2018b). Furthermore, Carlos-Vivas et al. (2018b) reported
a signicant increase in 30 m time (4.3%, ES = 0.99) and signicant decreases in Vo
(5.2%, ES 1.03), Fo (5.9%, ES 0.85) and RFmax (4.6%, ES 0.93) with this
loading. Three studies used 15% BM (Carlos-Vivas et al., 2018a; Cronin et al., 2008;
Konstantinos et al., 2014) with signicant increases in split times (1050 m 7.510%, ES
= 1.62.0) and contact time (14.315.3%, ES = 1.802.10), while signicant decreases
were found in ight time (8.3% to 9.8%, ES = 0.63 to 0.78), step frequency (2.7%
to 6.1%) and step length (% unknown). From the three studies that used 20% BM
(Carlos-Vivas et al., 2018b; Cronin et al., 2008; Konstantinos et al., 2014) signicant
increases in split times (1050 m 9.311.7%, ES = 2.43.5) and contact time
(14.719.6%, ES = 2.03.1) were found, while signicant decreases occurred in Vo
(9.2%, ES = 1.97), Vmax (8.4%, ES = 1.94), ight time (12.0% to 14.6%, ES =
0.88 to 1.03), step frequency (2.7% to 6.1%) and step length (% unknown).
Moreover, signicant decreases in Vo (9.2%, ES = 1.97), Fo (11.2%, ES = 1.73),
Pmax (19.4%, ES = 1.85) and RFmax (8.3%, ES = 1.85) were found with this
loading (Carlos-Vivas et al., 2018b). Carlos-Vivas et al. (2018b) used the two heaviest
loads of 30% and 40% BM and found that 30 m sprint time was signicantly increased
(11.816.9%, ES = 2.523.11), while signicant decreases were found in Vo (12.6% to
17.3%, ES = 2.52 to 3.19) and Vmax (11.7%to 16.1%, ES = 2.51 to3.19).
Moreover, Fo (16.7% to 22.1%, ES = 2.53 to 3.30), Pmax (27.3% to 35.6%, ES =
2.64 to 3.44), RFmax (12.5% to 17.1%, ES = 2.61 to 3.39), and DRF (2.53.1%,
ES = 0.750.81) were all signicantly changed.
Two research groups performed vest loaded sprints on a non-motorised treadmill for
6 s with loads ranging from 5% to 21.8% BM (Cross, Brughelli, & Cronin, 2014;
Simperingham & Cronin, 2014). Sprints with 5% BM resulted in contact time being
signicantly increased (3.84.7%, ES = 0.58) during the acceleration and maximum
velocity phases, while ight time was only signicantly decreased (15%, ES = 0.44)
during the acceleration phase. Moreover, vest loading of 5% BM signicantly decreased
peak vertical ground reaction force (5.4%, ES 0.58, acceleration phase, 6.4%, ES =
0.53, maximum velocity) and mean vertical ground reaction force (3.8%, ES = 0.55,
acceleration, 4.0%, ES = 0.50, maximum velocity) (Simperingham & Cronin, 2014).
Peak velocity (3.6% ES = 0.38) was signicantly decreased with vest loads of 10.9%
BM, while during the maximum velocity phase step length (4.4%, ES = 0.33), ight
time (17.4%, ES = 0.89), and contact time (4.19.2%, ES = 0.981.67) were signi-
cantly changed (Cross et al., 2014). No signicant changes in kinetics were found with
this load. The heavier 21.8% BM vest load resulted in signicant decreases in peak
velocity (5.7%, ES = 0.57), step length (4.4%, ES = 0.34, maximum velocity phase)
and ight time (18.9% to 26.7%, ES = 1.06 to 1.67), with increases in contact time
(9.2% ES = 1.67, maximum velocity phase) (Cross et al., 2014). Moreover, signicantly
increased peak vertical ground reaction force (8.2%, ES = 0.70, maximum velocity
phase), mean vertical ground reaction force (10.6%, ES 1.32%, and 11.1%, ES = 1.16,
acceleration and maximum velocity phases, respectively), and decreased peak power
output (14.3%, ES = 0.47, maximum velocity phase) were found with this loading
(Cross et al., 2014).
SPORTS BIOMECHANICS 9
Longitudinal eects of weighted vests on sprint-running
The longitudinal eects of weighted vests training on sprint-running performance and
kinematics are reported from ve studies (Table 3). No kinetics were reported from any
of the studies. The vest loads used ranged from 5.6% to 18.9% BM with overground
sprints being performed over 10 m to 55 m. Two studies utilised vest loading only
during training sessions (Clark, Stearne, Walts, & Miller, 2010; Rey et al., 2017), while
the remaining three studies had participants wear the vests for the majority of the day
for at least three days per week (Barr, Gabbett, Newton, & Sheppard, 2015; Rantalainen,
Ruotsalainen, & Virmavirta, 2012; Scudamore et al., 2016). Three weeks of vest loading
with 5.6% BM improved velocity during a 10 m sprint by 1.3% (p > 0.05, ES = 0.37)
(Rantalainen et al., 2012) while incremental vest loading (11.616.1% BM) over the
same time period resulted in a signicant improvement (1.5%, ES = 1.8) in 36.6 m time
(Scudamore et al., 2016). In contrast, during a shorter eight-day training period, 12%
BM loading had no signicant eect on 10 m or 40 m sprint time, though contact time
was signicantly decreased (8.9%, ES = 0.09) during the maximum velocity phase (Barr
et al., 2015). No signicant changes were found in sprint time or kinematics over
a 55 m distance following a seven-week training period with 18.5% BM (Clark et al.,
2010). However, signicant improvements in 10 m (9.4%, ES = 1.77) and 30 m (6.1%,
ES = 3.30) sprint performance were found with 18.9% BM vest loading following
a 6-week training period (Rey et al., 2017).
Discussion and implications
Acute eects of weighted vests on sprint-running performance
The acute eects of weighted vest sprint-running were reported from six studies.
Weighted vest loading (540% BM) was found to signicantly increase sprint times
in over ground sprint-running at all distance (10 m to 50 m), with measures of velocity
signicantly decreased in a linear fashion with incremental vest loads. Carlos-Vivas
et al. (2018b) found incremental loads of 10% BM resulted in maximum velocity being
decreased by 45% with each increment. It appears that weighted vest loading had
a greater eect on sprint performance during the maximum velocity phase than the
acceleration phase. Cronin et al. (2008) reported that 15% and 20% BM vest loading
produced greater changes at 30 m (9.611.7%) compared to 10 m (7.510%), while at
the same distance Konstantinos et al. (2014) using vest loads of 8%, 15%, and 20% BM
found similar results when comparing 30 m (4.6%, 6.9%, 9.6%) to 10 m (4.1%, 6.9%,
9.2%) distances. Konstantinos et al. (2014) also reported 40 m and 50 m sprint times
and found that greater increases in time were found at 40 m (5.1%, 7.9%, 9.9%)
compared to 50 m (4.6%, 7.3%, 8.2%) with all loads, respectively. Reasons, why the
40 m time was more eected than the 50 m time, are unknown, though Konstantinos
et al. (2014) reported that participants reached their maximum velocity between 20 and
40 m, thus it could be speculated that vest loading has a greater eect on attaining
maximum velocity than maintaining maximum velocity. Furthermore, as sprints were
performed from a ying start, participants may have already been decelerating
(fatiguing).
10 P. MACADAM ET AL.
Cronin et al. (2008) assessed changes in step kinematics during overground sprinting
and reported signicantly longer contact times, and signicantly shorter ight times,
step frequencies and step lengths. Contact times (14.319.6%) and ight times (8.3%
to 14.6%) were found to be more aected than step frequency (~-2.6 to 6.1%).
Regarding kinetics, incremental loads of 10% BM (10% to 40% BM) were found to
signicantly decrease maximum horizontal force by 67% and maximum horizontal
power output by 1114% with each increment increase (Carlos-Vivas et al., 2018b).
While incremental loads of 5% BM (5% to 15% BM) resulted in similar levels of
decreases (4.3% to 4.7%) in maximum horizontal power output, in a similar study
(Carlos-Vivas et al., 2018a). Carlos-Vivas et al. (2018b) was the only study to report the
maximum ratio of forces and decrease in ratio of forces, with all loads (1040% BM)
signicantly decreasing maximum ratio of forces (4.6% to 17.1%), while decreases in
ratio of forces were only signicantly changed (2.53.1%) with loads of 30% BM.
Therefore, potential reasons for the acute decreases in sprint performance appear to
result from the weighted vest overloading a participant during the stance phase to such
an extent that lower levels of horizontal force and power are produced.
From the two studies (Cross et al., 2014; Simperingham & Cronin, 2014) that used
weighted vests (521.9% BM) during treadmill sprints, similar outcomes to over ground
sprint kinematics were reported, that is contact and ight times were more aected by
vest loading than step frequency and length, and the maximum velocity phase was more
aected than the acceleration phase. Contact times were signicantly increased
(3.89.2%) and ight times were signicantly decreased (15% to 26.7%) with all
vest loads with greater changes found in the maximum velocity phase compared to the
acceleration phase. In contrast, only step length was signicantly decreased (4.4%)
with loads of 10.9% with step frequency unchanged, while velocity was also only
signicantly decreased with vest loads of 10.9% BM (3.6% to 5.7%). Vertical ground
reaction force was signicantly decreased with 5% BM loading (5.4% acceleration,
6.4%, maximum velocity), unaected with 10.9% BM, and signicantly increased
(10.6% acceleration, 11.1% maximum velocity) with 21.8% BM. Similar to kinematic
changes, greater changes in vertical ground reaction force were found during the
maximum velocity phase as compared to the acceleration phase. It would seem that
loads >10% BM are required to signicantly decrease vertical ground reaction forces.
Longitudinal eects of weighted vests on sprint-running performance
The eects of weighted vest loading on sprint-running performance were investigated in
ve studies. All research groups reported improvements in velocity and sprint times,
though not all ndings were statistically signicant. Due to the dierences in training
periods (8 days, 3 weeks, 6 weeks and 7 weeks), sprint distances (10, 30, 36.6, 40 and 55 m)
and vest loads (5.6%, 11.616.1%, 12%, 18.5% and 18.9% BM) inter-study comparisons are
problematic and should be interpreted with caution. In addition, the total training sessions
with a weighted vest varied between studies, and three of the studies used a hypergravity
intervention i.e., meaning participants wore the weighted vest for most of the day.
Previously hypergravity interventions have been found to elicit signicant improve-
ments in jump performance, lower limb power output, and a rightward shift in the force-
velocity prole following a 3-week period with loads ranging 713% BM (Bosco, 1985;
SPORTS BIOMECHANICS 11
Bosco, Rusko, & Hirvonen, 1986;Boscoetal.,1984). However, comparable changes are
not apparent in sprint-running studies most likely due to the methodological dierences
between studies. Rantalainen et al. (2012) and Scudamore et al. (2016) both utilised the
same 3-week hypergravity training period used by Bosco (Bosco, 1985;Boscoetal.,1986,
1984). A signicant improvement in 36.6 m sprint time (1.5%) was found with incre-
mental weekly vest loading (11.616.1% BM) in tness trained participants (Scudamore
et al., 2016). While an increase in velocity (1.3%) was reported over 10 m following vest
loading of 5.6% BM in sedentary participants, the authors reporting the ndings were not
signicant (Rantalainen et al., 2012). Dierences in ndings between studies may relate to
the greater load used by Scudamore et al. (2016) coupled with a greater number of training
sessions completed (9 vs. 6). The dierences in participants training backgrounds may also
have resulted in the tness trained participants being able to cope with the additional vest
loading, whereas the sedentary participants may have struggled with exercising with an
additional overload. Moreover, it has been proposed that weighted vests may have
agreatereect on maximum velocity sprinting compared to acceleration phase sprinting,
thus the dierences in sprint distance (10 m vs. 36.6 m) should be considered as
confounding conclusions. The third study to employ hypergravity loading was completed
on rugby athletes and measured performance changes at 10 m and 40 m, however, this
study used a much shorter training period (eight days) compared to the other studies
reviewed. Though no changes in sprint performance at either distance were found
following the 8-day intervention, Barr et al. (2015) did report that two of the eight
participants improved sprint performance highlighting that responses to vest loaded
training are participant specic. As this study had the shortest training period, a longer
duration may have been required to elicit signicant improvements, though the signicant
decrease in contact time (maximum velocity phase) in this short period illustrated that
positive adaptations were apparent, thus with a greater duration (e.g., 3weeks)signicant
improvements in sprint performance may have eventuated.
The remaining two studies both used similar vests magnitudes (18.5% and 18.9%
BM) and completed a similar number of training sessions (12 and 13) though diered
in sprint distance (30 m vs. 55 m) (Clark et al., 2010; Rey et al., 2017). Clark et al. (2010)
reported a non-signicant improvement in sprint time (1.2%) measured over 18.5 m to
55 m, while signicant improvements in 10 m (9.4%) and 30 m (6.1%) sprint perfor-
mance were reported by Rey et al. (2017). Of note, both studies found that sprint
performance from the control groups were similar to the weighted vest groups changes
with no signicant dierences between the groups. Therefore, sprint training, indepen-
dent of load, had a positive eect on sprint performance, thus questioning the need for
resisted vest loading. However, Rey et al. (2017) did note that the nature of improve-
ments in sprint performance were dierent between the groups with the control group
achieving greatest improvement at 10 m, whereas the vest loaded group had the greatest
improvement at 30 m. This nding supports the proposal that vest loading may be
more benecial for maximum velocity phase sprinting due to the increased vertical load
at foot contact.
In summary, weighted vest loading has a greater impact on contact and ight times
than step length and frequency variables, which inuences the acceleration of the bodys
centre of mass downwards, relating to reduced or similar vertical ground reaction force
until the use of relatively heavy vest loads (>20% BM). Horizontal force and power
12 P. MACADAM ET AL.
production were reduced with vest loading as little as 5% BM. Though both acceleration
and maximum velocity phases were aected, the additional vertical loading from the vest
seems to have a greater aect during maximum velocity sprinting on both kinematics and
kinetics resulting in greater decreases in sprint times at maximum velocity phases. It is
possible that the maximum velocity phase of sprint running is more sensitive to the
vertical loading with vest loads due to the importance of vertical force production in
producing maximum velocity sprint running (Weyand, Sternlight, Bellizzi, & Wright,
2000). Moreover, Cronin and Hansen (2006) suggested that a weighted vest increased
the vertical load during ground contact, increasing vertical braking forces, and may
eectively overload the stretch-shortening cycle, thus has better application during max-
imum velocity speed. Longitudinal training with weighted vests has focused on two
general methodologies: hypergravity intervention during activities of daily living and
hypergravity training while sprint running. One is highly specic to the intended outcome
(resistance training at high velocity, i.e., wearing vest while sprinting) and the other is
opposing training specicity (wearing a load all day likely slows down activities of daily
living and is resistance training at slow velocities). Studies that used weighted vests during
sprint running sessions found that sprint performance from the control groups were
similar to the weighted vest groupschangesno signicant dierences between the
groups. Large variations in study methodologies (use of WR, training period, WR amount,
populations used) make it inappropriate to formulate discrete conclusions on the long-
itudinal eects of weighted vests on sprint running performance.
Limitations and future research
Due to the heterogeneity of the included studies (magnitude of the load, intervention
duration, and participants) caution is warranted when interpreting the ndings of this
review and their implications for practice. The magnitude of loads (5% to 40% BM)
diered considerably in studies as did participant training backgrounds meaning that it
is dicult to clearly establish the optimum loading for sprint-running. Three of the ve
longitudinal studies involved the weighted vest being worn for most of the day, thus
making the comparison to other studies or generalisation to typical practice proble-
matic. Moreover, the vest was not worn for two studies during sport training events.
Future research is required to more fully understand the acute and longitudinal
eects of weighted vests on sprint-running performance. It is recommended that
research replicates similar vest magnitudes and sprint distances to verify the ndings
of this review. The sporting backgrounds and technical prociency of the participants
can inuence both the kinematic and kinetic changes during weighted vest interven-
tions. This was particularly evident during the longitudinal studies when highly trained
participants were compared to recreationally or sedentary participants. Moreover,
athletes with dierent levels of experience and skills may require modied loading
magnitudes (i.e., more or less %BM) to enable positive sprint adaptation. Whether vest
loading of > 40% BM would be benecial in sprint-running has also yet to be
investigated though the practicality of loading and attaching that amount of resistance
to the torso would be challenging and may be more suitable to sledge loading where
greater loads can easily be applied.
SPORTS BIOMECHANICS 13
Conclusion
Though several limitations and gaps exist in the research, some general comments can
be made about the use of weighted vests. Sprinting with a weighted vest results in
a signicant acute reduction in velocity and increase in sprint times during over ground
sprint-running with loads of 540% BM, while velocity was only signicantly decreased
with vest loads of 10.9% BM in treadmill sprints. During weighted vest sprinting,
contact and ight times were more aected by loading as opposed to step frequency and
step length. The reduction in ight time, which reduced the inuence of the accelera-
tion of the bodys centre of mass downwards, resulted in the vertical ground reaction
force being reduced or remaining relatively the same until a relatively heavy vest load (>
20% BM) was used. Incremental loads of 10% BM were found to signicantly decrease
maximum horizontal force by 67% and maximum horizontal power output by
1114%. Though some performance improvements with weighted vest sprinting were
found in longitudinal studies of three weeks or more, the full benets of this training
method on mechanistic determinants and performance are yet to be clearly established.
Future research is required to dene the optimum load and volume to clearly establish
if there are any training benets to this form of resisted sprinting.
Disclosure statement
No potential conict of interest was reported by the authors.
ORCID
Paul Macadam http://orcid.org/0000-0002-2077-5386
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16 P. MACADAM ET AL.
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This study quantified the physiological and biomechanical effects of the 20lb (9.07kg, males) and 14lb (6.35kg, females) weighted vest used in CrossFit, and whether they predisposed to injury. Twenty subjects (10 males, 10 females) undertook walking (0%, 5% and 10% gradient) and running trials in two randomised study visits (weighted vest/no weighted vest). Physiological demand during walking was increased with the vest at 10% but not 5% or 0% with no change in gait variables. In the running trial, the weighted vest increased oxygen uptake (males; females) (+0.22L/min, p < 0.01; +0.07L/min, p < 0.05), heart rate (+11bpm, p < 0.01; +11bpm, p < 0.05), carbohydrate oxidation (+0.6g/min, p < 0.001; +0.2g/min, p < 0.01), and energy expenditure (+3.8kJ/min, p < 0.001; +1.5kJ/min, p < 0.05) whilst blood lactate was increased only in males (+0.6mmol/L, p < 0.05). There was no change in stride length or frequency. Weighted vest training increases physiological stress and carbohydrate oxidation without affecting measured gait parameters. Practitioner Summary We examined the effect of weighted vest training prescribed in CrossFit (20 lb/9.07kg, males and 14 lb/6.35kg, females) in a randomised controlled trial. We found that physiological stress is increased in both sexes, although three-fold greater in males, but with no change in biomechanical gait that predisposes to lower-limb injury.
... Times to cover all distances increased in both BB2.5 and BB5 conditions over BW condition. These findings are consistent with other studies involving sprinting with increasing overloads [13,32,33]. In these studies, sprinters performed sled towing and, as the overload increased, the time to cover 20 and 30 m distances underwent a significant deterioration [13,32]. ...
... In these studies, sprinters performed sled towing and, as the overload increased, the time to cover 20 and 30 m distances underwent a significant deterioration [13,32]. The same increase in sprint times was presented for weighted vests in a recent review [33]. This deterioration in sprint times is reflected by a reduction in V0. ...
... No further increase in force production was found, as it stabilized for 30% and 40% conditions. Conversely, a recent review showed that weighted vests, with overloads ranging from 5% to 40% of the athlete's body mass, decreased force production by 6-7% and power production by 11-14% [33]. ...
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Background: Effective sprinting requires large acceleration capabilities. To accelerate, large amount of force must be produced and applied effectively. The use of different implements such as sleds and vests can increase the amount of force produced and alter sprinting effectiveness. We propose the use of increasing overload via the Bulgarian Bag (BB) as a means to modify athletes' sprint and acutely increase force and power production. Methods: 24 young athletes performed three sprints over 20 m in three different conditions: unloaded (BW) and loaded with BB weighing 2.5% (BB2.5) and 5% (BB5) of the athlete's body mass. Sprint times at 2.5, 5, 10, 15, and 20 m were acquired and used to compute the force-velocity relationship for the sprints. Maximal velocity (V0), peak force (F0), peak power (PP), and decrease in ratio of force (DRF) were computed. Results: the additional load caused a decrease in sprint times (p < 0.05) and V0 (p = 0.028), conversely no differences were found for F0 (p = 0.21), PP (p = 0.50), and DRF (p = 0.83). Conclusions: Based on those findings, BB can be an alternative method to effectively overload sprint training toward improving sprinting performance.
... However, these changes in asymmetry did not seem to be at the expense of the speed changes between the conditions and even less of performance . As found in previous studies, pole carriage and more generally extra-weight or arm swing restriction decreased the step length Cross, Brughelli, & Cronin, 2014;Macadam, Cronin, & Feser, 2019). However, one can note that during competition, step length reached similar level than in SP condition. ...
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In pole vaulting, take-off speed is considered as a major determinant of performance. Pole carriage could affect the speed acquired during the approach and at the take-off. This study investigated different types of runs performed randomly by young male and female expert athletes: maximal sprint, maximal pole carriage run, maximal run-up with simulated pole plant and competition situation. Speed profile was determined with a radar gun and spatiotemporal parameters were recorded for the last 20 m of the approach with the Optojump Next system. For both genders, mechanical variables were compared using two-way ANOVAs with repeated measurements. Pole carriage represents the main cause of speed decrease for both men (−5.8%) and women (−6.2%). A step rate decrease during pole carriage was pointed out with an increase of contact time for both men and women. Significant speed decrease was observed for women at the take-off compared to pole plant simulation (−4.3%), while not for men. Those results provide a new insight for pole vault training allowing to update training process with specific exercises leading to reduce speed loss at take-off.
... Improved activation would increase angular acceleration of the leg during swing, increasing running speed. However, there is no correlation between training-induced increases in MVC extensor torques and running economy following RT, implying that improvements in hip and knee joint torques might contribute to increase maximal but not submaximal running speed used during distance races (Alcaraz-Ibanez and Rodriguez-Perez, 2018;Macadam et al., 2019;Trowell et al., 2019;Young, 2006). ...
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Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.
... Because directional changes play a key role in these sports, coaches and sport scientists should focus more explicitly on developing and implementing innovative speed training schemes, better adapted and, principally, integrated to the context of the game. In this regard, the constant execution of deceleration, acceleration, and reacceleration drills, as well as the use of eccentric strength training and weighted vests, may be highly recommendable (21,29,35). Undoubtedly, these practices should be properly combined with other conventional training methods (e.g., resistance training, resisted sprints, and plyometrics) and frequently distributed over the entire training and competitive season. ...
Article
The primary aim of this study was to examine the differences in change of direction (COD) deficit between elite futsal, soccer, handball, and rugby players. A secondary aim was to compare the performance in both COD and linear speed tests among these athletes. One-hundred and sixty-one elite male players from four team-sports performed a 20-m linear sprint speed and a Zigzag COD speed test. The COD deficit was calculated as the difference between linear and Zigzag test velocities. Differences in COD speed, COD deficit, and sprint velocity were assessed via one-way analysis of variance. The significance level was set at P<0.05. Soccer players displayed significantly lower performance than the remaining team-sports, and rugby players performed better than all the other groups in the Zigzag COD test. Moreover, the COD deficit was significantly higher in soccer players in comparison with the other disciplines (P<0.05). No differences were observed in the COD deficit among rugby, futsal, and handball players (P>0.05). In summary, soccer players were slower than futsal, handball, and rugby players to change direction and presented the greatest COD deficit magnitude. In contrast, the fastest athletes in the COD speed test (rugby players) were not more effective than futsal and handball players at changing direction (as they exhibited similar levels of COD deficit). Coaches should be aware of this evidence, which reinforces previous findings, indicating that very specialized training strategies might be required to improve COD performance in professional athletes.
... One means of progressive overload is through wearable resistance (WR), which involves an external load being attached to areas of the body enabling a sport-specific form of loading [6,7]. Previous studies have used a wide magnitude of loads (<1% to 40% body mass (BM)) attached to the trunk or limbs during different sporting actions [6,8]. Though heavier loads (>10% BM) have been used with trunk WR, lighter WR loads (<8.5% BM) have been sufficient to significantly increase metabolic demands compared to unloaded walking and running, indicated by increases in oxygen consumption (VO2), heart rate (HR), energy workload and energy cost [6]. ...
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The aim of this study was to determine the acute metabolic effects of different magnitudes of wearable resistance (WR) attached to the thigh during submaximal running. Twenty endurance-trained runners (40.8 ± 8.2 years, 1.77 ± 0.7 m, 75.4 ± 9.2 kg) completed six submaximal eight-minute running trials unloaded and with WRs of 1%, 2%, 3%, 4% and 5% body mass (BM), in a random order. The use of a WR resulted in a 1.6 ± 0.6% increase in oxygen consumption (VO2) for every 1% BM of additional load. Inferential based analysis found that the loading of ≥3% BM was needed to elicit any substantial responses in VO2, with an increase that was likely to be moderate in scale (effect size (ES) ± 90% confidential interval (CI): 0.24 ± 0.07). Using heart rate data, a training load score was extrapolated to quantify the amount of internal stress. For every 1% BM of WR, there is an extra 0.17 ± 0.06 estimated increase in training load. A WR ≥3% of BM was needed to elicit substantial responses in lactate production, with an increase which was very likely to be large in scale (ES ± 90% CI: 0.41 ± 0.18). A thigh-positioned WR provides a running-specific overload with loads ≥3% BM, resulting in substantial changes in metabolic responses.
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Purpose: Speed training and short distance sprints have become an essential component of preparation for professional football players. Current trends in speed training have included the application of non-curved, manual treadmills, as they may enhance peak speeds with less biomechanical stress. A lack of data currently exists in regards to the effectiveness of different settings and peak speed response. Therefore, we proposed to compare peak speeds during different settings of non-curved, manual treadmills. It was hypothesized that as resistance/incline increased, peak sprinting speeds would decrease and vice versa. Methods: Fourteen male professional football players (27.14 ± 3.11 yrs., 183.93 ± 8.52 cm, 100.36 ± 15.60 kg) sprinted at peak speeds during four different incline/resistance bouts. Paired samples T-tests examined differences between bouts, and significance was set at p ≤ 0.008. Results: A significant difference (p < 0.001) existed for peak speeds between each incline/resistance bout (i.e. INC15R8, INC15R5, INC20R3, INC20R1). Conclusions: The observed data differences existed between all bouts, indicating that as resistance and/or incline increased, peak speed decreased. This also indicated that as resistance and/or incline decreased, peak speed increased during sprint bouts in professional football players.
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Ben Brahim, M, Bougatfa, R, Makni, E, Gonzalez, PP, Yasin, H, Tarwneh, R, Moalla, W, and Elloumi, M. Effects of combined strength and resisted sprint training on physical performance in U-19 elite soccer players. J Strength Cond Res XX(X): 000–000, 2020—This study assessed the effects of combined muscular strength and resisted sprint training using both sled and weight vest compared with regular soccer training on physical fitness of lower limbs in U-19 elite soccer players. Thirty-four male soccer players (age: 18.8 ± 0.8 years, height: 1.81 ± 0.05 m, body mass: 76.4 ± 4.9 kg, and body fat mass: 11.3 ± 4.2%) were randomly assigned into a resisted sprint training group (RSTG, n = 20), using both weight vest and sled, and a control group (CONTG, n = 14). Sprinting ability (5 m and 20 m), squat jump (SJ) and counter-movement jump (CMJ) tests, 1 repetition maximum of half-back squat (1RM half-back squat), and soccer ball-shooting speed were assessed before and after a 6-week training program. Within-group interactions showed significant combined muscular strength and resisted sprint training effects were observed for all the tests' measurements (effect sizes = 0.97 and 3.69 for 20-m sprint and SJ, respectively). However, significant increases of performances were observed for 5-m and 20-m sprinting time ( = 0.25, p < 0.01 and = 0.22, p < 0.01, respectively), SJ and CMJ ( = 0.78, p < 0.0001 and = 0.34, p < 0.001, respectively), 1 repetition maximum (1-RM) half-back squat ( = 0.45, p < 0.0001), and soccer ball-shooting speed ( = 0.41, p < 0.0001) in RSTG with large effect size, whereas the CONTG showed significant performances increase only for CMJ (p < 0.05), 1RM half-back squat (p < 0.01), and soccer ball-shooting speed (p < 0.05). We conclude that combined strength and both horizontal (weighted sled) and vertical (weighted vest) resisted sprint training are more effective than regular soccer training for enhancing sprinting and jumping abilities as well as ball-shooting speed in soccer.
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THIS COLUMN DISCUSSES TWO RELATED, BUT IMPORTANTLY DIFFERENT, APPROACHES TO ENHANCING POWER; ASSISTED AND RESISTED TRAINING. UNDERSTANDING BOTH MODALITIES ALLOWS THE STRENGTH AND CONDITIONING PROFESSIONAL TO DISCERN THE ROLE OF EACH IN ENHANCING JUMP AND SPRINT PERFORMANCE.
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Background Wearable resistance training (WRT) provides a means of activity- or movement-specific overloading, supposedly resulting in better transference to dynamic sporting performance. Objective The purpose of this review was to quantify the acute and longitudinal metabolic, kinematic and/or kinetic changes that occur with WRT during walking, running, sprint running or jumping movements. Data SourcesPubMed, SPORTDiscus, Web of Science and MEDLINE (EBSCO) were searched using the Boolean phrases (limb OR vest OR trunk) AND (walk* OR run* OR sprint* OR jump* OR bound*) AND (metabolic OR kinetic OR kinematic) AND (load*). Study SelectionA systematic approach was used to evaluate 1185 articles. Articles with injury-free subjects of any age, sex or activity level were included. ResultsThirty-two studies met the inclusion criteria and were retained for analysis. Acute trunk loading reduced velocity during treadmill sprint running, but only significantly when loads of 11 % body mass (BM) or greater were used, while over-the-ground sprint running times were significantly reduced with all loads (8–20 %BM). Longitudinal trunk loading significantly increased jump performance with all loads (7–30 %BM), but did not significantly improve sprint running performance. Acute limb loading significantly increased maximum oxygen consumption and energy cost with all loads (0.3–8.5 %BM) in walking and running, while significantly reducing velocity during sprint running. LimitationsThe variation in load magnitude, load orientation, subjects, testing methods and study duration no doubt impact the changes in the variables examined and hence make definitive conclusions problematic. ConclusionsWRT provides a novel training method with potential to improve sporting performance; however, research in this area is still clearly in its infancy, with future research required into the optimum load placement, orientation and magnitude required for adaptation.
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Twenty four male Sport Science students, were assigned in this study in order to be examined the acute effects of different loading conditions on acceleration, maximum speed and final performance of a 50m sprint run. A countermovement jump and a 50m run without and with extra loading - 8, 15, 20% of subjects' BM were performed in order leg power and running performance to be measured. ANOVA revealed significant interaction between loading conditions and performance (Wilks ËF = 31.34, p = 0.000, n2 = 0.967). The 8% B.M. loading significantly affected performance at 40 m by 4.6-4.7% while the 15% BM loading at 20 and 40m by 7.3 and 7.4% respectively. The 20% BM loading affected similarly running performance at 10m and 40m causing an increase in performance by 9.9% at both distances. Significant correlations were found between leg power and running performance for the selected distances at the loading conditions of 0, 8, 15% BM (r = –0.440 – 0.553), while a correlation between leg power and running performance with the load of 20%B.M. was found only for the distances 30, 40 and 50m (r = –0.419 – 0.565). Subjects with higher leg power were more affected by large loads (15-20% BM) during the acceleration phase, while in those with lower leg power decreases occurred by all loading conditions. Consequently, resistance speed training using a weighted vest emerges an excellent means for either phase of the 0-50meters.
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International Journal of Exercise Science 9(2): 149-158, 2016. This study examined the effects of a non-traditional training method, hypergravity training (HT), on anaerobic performance. Highly active men (n = 9) completed a 3 week HT protocol in which weighted vests were worn 8 h/day, 4+ days/week separate from training. Vest loads were 11.2 ± 0.6% of body mass during week one, and increased to 13.2 ± 0.7% (week 2), and 16.1 ± 0.4% (week 3). Performance testing included power clean 1-RM (PC), counter movement jumps, 4 continuous jumps, 36.6 m sprints (SP), a 137.2 m short shuttle run (SSR), and a 274.3 m long shuttle run (LSR). A 3 week non-hypergravity training period (NHT) proceeded HT. Baseline SP improved from 4.69 ± 0.29 s to 4.58 ± 0.22 s post-treatment, and regressed after NHT (4.69 ± 0.24 s) (p = 0.006, ES = 1.80). Improvements in SSR (p = 0.012, ES = 1.71) occurred from baseline (26.7 ± 1.5 s) to post-treatment (26.2 ± 1.4 s), followed by a return to near-baseline values (26.9 ± 1.8 s). Jumping tasks displayed similar trends, but no statistical differences and modest effect sizes (0.51-0.62) were found except for improved ground contact time during repeated jumps post-HT (ES = 2.26). PC and LSR performances did not improve. Three weeks of HT significantly enhanced short running task performances and decreased ground contact time between 4 continuous jumps. HT may be incorporated into training programs prior to key points in an athletic season without hindering the quality of regular training session activities.
Article
Purpose:: To describe the load-velocity relationship and the effects of increasing loads on spatio-temporal and derived kinetics variables of sprinting using weighted vest (WV) in soccer players and determining the load that maximized power output. Methods:: Twenty-three soccer players (age: 20.8±1.5 years) performed ten maximal 30-m sprints wearing a WV, with five different loads (0, 10, 20, 30 and 40% body mass (BM). Sprint velocity and time were collected using a radar device and wireless photocells. Mechanical outputs were computed using a recently developed valid and reliable field method that estimates the step-averaged ground reaction forces (GRF) during over ground sprint acceleration from anthropometric and spatio-temporal data. Raw velocity-time data were fitted by an exponential function and used to calculate the net horizontal GRF and horizontal power output. Individual linear force-velocity relationships were then extrapolated to calculate the theoretical maximum horizontal force (F0) and velocity, and the ratio of force application (RF: proportion of the total force production that is directed forward at sprint start). Results:: Magnitude-based inferences showed an almost certain decrease on F0 (effect size [ES]=0.78-3.35), maximum power output (ES=0.78-3.81), and maximum ratio of force (ES=0.82-3.87) as the load increased. The greatest changes occurred with loads heavier than 20% BM, especially in RF. Additionally, the maximum power was achieved under unloaded condition. Conclusions:: Increasing load on WV sprinting affects the spatio-temporal and kinetic variables. The greatest change in RF happened with loads heavier than 20% BM. Thus, we recommend the use of loads ≤20% BM for WV sprinting.
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Background Chronic pain has a substantial negative impact on work‐related outcomes, which underscores the importance of interventions to reduce the burden. Spinal cord stimulation (SCS) efficiently causes pain relief in specific chronic pain syndromes. The aim of this review was to identify and summarize evidence on returning to work in patients with chronic pain treated with SCS. Materials and Methods A systematic literature review was performed including studies from PubMed, EMBASE, SCOPUS, and Web of Science (up till October 2017). Risk of bias was assessed using a modified version of the Downs & Black checklist. Where possible, we pooled data using random effects meta‐analysis. The study protocol was registered prior to initiation of the review process (PROSPERO CRD42017077803). Results Fifteen full‐text articles (total articles screened: 2835) were included. Risk of bias for these articles was scored low. Seven trials provided sufficient data and were judged similar enough to be pooled for meta‐analysis on binary outcomes. SCS intervention results in a higher prevalence of patients at work compared with before treatment (odds ratio [OR] 2.15; 95% confidence interval [CI], 1.44–3.21; I² = 42%; p < 0.001). SCS treatment also results in high odds to return to work (OR 29.06; 95% CI, 9.73–86.75; I² = 0%; p < 0.001). Conclusions Based on available literature, SCS proved to be an effective approach to stimulate return to work in patients with specific chronic pain syndromes.
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Carlos-Vivas, J, Freitas, TT, Cuesta, M, Perez-Gomez, J, De Hoyo, M, and Alcaraz, PE. New tool to control and monitor weighted vest training load for sprinting and jumping in soccer. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to develop 2 regression equations that accurately describe the relationship between weighted vest loads and performance indicators in sprinting (i.e., maximum velocity, Vmax) and jumping (i.e., maximum height, Hmax). Also, this study aimed to investigate the effects of increasing the load on spatio-temporal variables and power development in soccer players and to determine the "optimal load" for sprinting and jumping. Twenty-five semiprofessional soccer players performed the sprint test, whereas a total of 46 completed the vertical jump test. Two different regression equations were developed for calculating the load for each exercise. The following equations were obtained: % body mass (BM) = -2.0762·%Vmax + 207.99 for the sprint and % BM = -0.7156·%Hmax + 71.588 for the vertical jump. For both sprinting and jumping, when the load increased, Vmax and Hmax decreased. The "optimal load" for resisted training using weighted vest was unclear for sprinting and close to BM for vertical jump. This study presents a new tool to individualize the training load for resisted sprinting and jumping using weighted vest in soccer players and to develop the whole force-velocity spectrum according to the objectives of the different periods of the season.
Article
The purpose of this study was to assess the effect resisted sprint training using weighted vests (WV) compared with unresisted sprint training (US) on physical fitness (countermovement jump, 10 m sprint, 30 m sprint and repeated sprint ability (RSA)) in amateur male soccer players. 19 soccer players (age: 23.7±4.5 years; height: 178.3±5.8 cm; body mass: 72.9±5.2 kg) were randomly assigned to a WV (n= 10) or a US (n= 9) group. The intervention program had to be carried out 2 times a week over 6 weeks. The only difference between the two interventions was that the WV group performed all the sprints with an additional weight of 18.9% ± 2.1% of body mass. Within-group analysis showed significant improvements (p<0.001) in 10 m and 30 m sprint performance from pretest to post-test in WB (+9.42% and +6.04%) and CTU (+10.87% and +5.10%). Players in both WV and US also showed significant enhancements in RSA average time, fastest time, and total time from pretest to posttest. Percentage changes in 30 m sprint performance, for both groups combined, had a very large correlation with percentage changes in average time of RSA. In the between-groups analysis, there were no differences between the sprint training groups (WV vs US) in any variable. In conclusion, the findings of this study indicate that both sprint training methods used seem to be effective to improve soccer related performance measures, and could be beneficial to players and coaches in field settings.