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A brief review on the role of maximal strength in change of direction speed

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BLUF This brief review will discuss the role that strength plays in effectively changing direction and will therefore provide justification for the need to train and maximise relative lower limb strength in athletes requiring superior change of direction speed. ABSTRACT Team field and court sports often demand the athlete to decelerate, change their direction, and accelerate again in response to a stimulus. All of this occurs in fractions of a second and needs to be completed in a shorter period of time than the athlete's opponent to be successful. The physical component of this quality is termed change of direction speed (CODS). In regard to training and improving CODS, there is currently disagreement on the efficacy of implementing traditional strength training methods as these primarily work through a vertical plane. Reviewing and discussing CODS and the necessary physical capacities that will lead to enhancement of this quality will help in making informed decisions for effective training methodologies. Therefore the primary purpose of this brief review was to identify and discuss the possible factors that influence CODS. The majority of the discussion focussed on the role of maximal relative strength in CODS performance and further discussion was conducted on testing methodologies. A search of the literature was completed to locate and examine any available articles that explored the relationship between strength and CODS. Principally, correlational and training studies were examined closely while studies investigating the kinematics of CODS movements were also evaluated. After the literature had been reviewed and discussed it was concluded that an athlete's relative maximal strength plays a significant role in determining CODS performance. Therefore when preparing team sport athletes for competition, strength training and weightlifting programs designed to improve maximal relative strength should be implemented to improve CODS.
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Journal of Australian Strength and Conditioning
Volume 23 | Issue 2 | April 2015
100
A Brief Review on the Role of Maximal Strength in Change of Direction Speed. J. Aust. Strength Cond. 23(2) 100-108. 2015 © ASCA.
Review of the Literature
A BRIEF REVIEW ON THE ROLE OF MAXIMAL STRENGTH IN CHANGE OF DIRECTION SPEED
David Watts
BLUF
This brief review will discuss the role that strength plays in effectively changing direction and will therefore provide
justification for the need to train and maximise relative lower limb strength in athletes requiring superior change of
direction speed.
ABSTRACT
Team field and court sports often demand the athlete to decelerate, change their direction, and accelerate again in
response to a stimulus. All of this occurs in fractions of a second and needs to be completed in a shorter period of time
than the athlete’s opponent to be successful. The physical component of this quality is termed change of direction
speed (CODS). In regard to training and improving CODS, there is currently disagreement on the efficacy of
implementing traditional strength training methods as these primarily work through a vertical plane. Reviewing and
discussing CODS and the necessary physical capacities that will lead to enhancement of this quality will help in making
informed decisions for effective training methodologies. Therefore the primary purpose of this brief review was to identify
and discuss the possible factors that influence CODS. The majority of the discussion focussed on th e role of maximal
relative strength in CODS performance and further discussion was conducted on testing methodologies. A search of
the literature was completed to locate and examine any available articles that explored the relationship between strength
and CODS. Principally, correlational and training studies were examined closely while studies investigating the
kinematics of CODS movements were also evaluated. After the literature had been reviewed and discussed it was
concluded that an athlete’s relative maximal strength plays a significant role in determining CODS performance.
Therefore when preparing team sport athletes for competition, strength training and weightlifting programs designed to
improve maximal relative strength should be implemented to improve CODS.
Key Words CODS, change of direction speed, agility, strength, power, speed.
INTRODUCTION
Agility is a vital requirement of success in most team sports (30), as the rapid changing of direction and velocity allows
athletes to gain positional advantage during competition (2-4, 11). Therefore determining the best possible methodology
to improve agility should be a major focus for the strength and conditioning coach who is working with a field or court
team sport. In doing so, the first step taken should be to acquire an understanding of the factors that influence
performance in an agility task. Young, James and Montgomery (36) had previously outlined the factors contributing to
agility performance and a modified version of the resulting flow chart is presented in Figure 1. They proposed that
technique and leg muscle qualities were two of the factors that influenced CODS. Specifically, technique included foot
placement, stride adjustments, and body lean. Leg muscle qualities incorporated strength, power and reactive strength.
More recently though Sheppard and Young (29) produced a literature review on the classification, training and testing
of agility. In this review they proposed the following definition of agility, “a rapid whole body movement movement with
change of velocity or direction in response to a stimulus” (29). The last phrase of their definition, ‘in response to a
stimulus’, outlines the difference between agility and CODS. Agility is sport specific, and is largely determined by the
perceptual abilities of the athlete. The influence of these cognitive factors in agility has been shown to be vital and must
not be underestimated as Gabbett, Kelly and Sheppard (9) stated in their discussion that “better players are sometimes
faster but almost always have superior decision making skills”. Therefore an athlete’s game knowledge and awareness
can make them appear far more agile than the result of their CODS test would suggest. Agility and CODS are often
used synonymously but this is done so incorrectly. They are each a distinct quality and should be tested and trained as
such. The following review focused solely on CODS and did not consider the cognitive aspects required in agility.
CODS has always been a high priority in the training and preparation of team sport athletes. Changes of direction and
speed are performed continuously and with a large degree of variation during competition. The athlete needs to develop
a high degree of competency with this skill to aid there on field performance. Evidence of this was found in a study of
senior female hockey players. In this study those athletes who had reached a higher representative level were
significantly quicker in a test of CODS, the Illinois agility run (23). While superior performance in a CODS task has even
been sensitive enough to distinguish between starting and non-starting players in an NCAA division one women’s
volleyball team (8). While these studies are only correlational and do not prove causation they still show a clear
relationship between CODS and performance in team sports.
The aim of this review was to closely investigate the available literature on CODS to provide evidence based training
recommendations for the S&C coach working with team sports. Previous reviews of CODS concluded that traditional
Journal of Australian Strength and Conditioning
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strength and power training methods, including increasing maximal relative strength, have failed to improve CODS (5).
This brief review aimed to explore the accuracy of that position by discussing in detail the biomechanics of a change of
direction, recent studies that were published after the latest review and the issues with the current testing methodologies
used in CODS research.
Figure 1 Factors influencing performance in agility (36).
METHODS
The author began the search for available literature by using both Google scholar and PubMed. The following keywords
were used in various combinations, “change of direction speed” “change of direction” “CODS” “COD” “agility” “strength”
and “power”. The quantity of keywords used was due to the array of nomenclature used synonymously with CODS.
The search for available literature continued by searching the Journal of Strength and Conditioning Research and the
Journal of Australian Strength and Conditioning. The same keywords were used as in the initial search. Following this
secondary search, the articles found were then reviewed more closely to determine whether or not the methodology
was of an acceptable standard. Methodological limits for acceptance revolved primarily around the testing protocols
used for both CODS and strength measures. Finally, additional papers were sourced manually through inspection of
the reference lists of articles that had already been reviewed. Articles were also accepted if they provided insight into
other components of CODS as outlined in the flow chart by Young, James and Montgomery (36). The results of the
correlational and training studies accepted for review were collated into two tables to form the results section of this
review. The review was completed purely as a qualitative investigation of the literature and no statistical analysis was
completed to produce quantitative results.
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RESULTS
Table 1 - Correlational relationship between CODS and max strength.
Study
Subjects
COD test used
Pearson correlation coefficient
(r) and magnitude of effect
n
Gender
Subject
description
Group
Name
# of
COD
Result -
(St Dev)
Negrete
and
Brophy
(25)
60
Male =
29
Female
= 31
College
students
n/a
Diamond
Functional
Test
many
m =
100s f =
135s
-0.595 (0.0001)
Large
Peterson,
Alvar &
Rhea (28)
54
Male =
19
Female
= 35
Collegiate
athletes
n/a
T-test
4
10.91s
(0.96)
-0.805 (0.05)
Large
Barnes, et
al (3)
29
Female
Division I,II
and III NCAA
VB players
n/a
Novel CODS
Test
3
5.93-
6.1s
(0.2)
-0.373 (0.01)
Moderate
Hori, et al
(21)
29
Male
Semi-pro ARF
players
n/a
5-5 COD
1
2.58-
2.65s
(0.10)
-0.51 (0.01)
Large
Chaouachi
et al (2009)
(6)
19
Male
Professional
basketball
players
n/a
T-test
4
9.7s
(0.2)
-0.18 (0.29)
Not
significant
Nimphius,
McGuigan
and
Newton
(26)
10
Female
Elite softball
players
n/a
505
Dominant
Side
1
NR
-0.60 (ns)
Not
significant
505 Non-
Dominant
1
NR
-0.85 (0.05)
Very
Large
2nd Base
Sprint
1
NR
-0.83 (0.05)
Very
Large
Arin,
Jansson
and
Skarpagen
(1)
20
Male
Soccer and IH
college
athletes
n/a
Modified
Pro-Agility
Test
2
4.94s
(0.15)
-0.606 (0.005)
Large
Spiteri &
Nimphius
(33)
24
Male =
12
Female
= 12
Recreationally
trained team
sport athletes
SG
n=12
Single 45
COD
moving at
4.5m/s ± 0.5
1
PSV =
2.50m/s
(0.37)
-0.89 (0.05)
Very
Large
-0.95 (0.05)
Nearly
Perfect
WG
n=12
PSV =
2.28m/s
(0.27)
-0.52 (ns)
Large
-0.13 (ns)
Small
#= number, n = sample size, m= male, f=female, IH= ice hockey, RL= rugby league, ARF= australian rules football, 1RM= one repetition
maximum, St Dev = standard deviation, NCAA = national collegiate athletic association, NP = not produced, NR= not reported, Rel=relative, PF=
peak force, BW= bodyweight, TT= total time, PSV= post stride velocity, SG= strong group, WG= weak group, n/a= not available, SL= single leg,
FS = front squat, VB= volleyball.
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Table 2 - Strength training studies and the effect on CODS.
Study
Sample
Training and testing
n
Gender
Description
Mode
and
duration
of
training
Group
Strength
test
%
Change
CODS
test
% Change
Effect size
and Hopkins
interpretation
(20)
Fry et al
(8)
14
Female
NCAA division
1 VB players
12 week-
pre-
season
periodized
S&C
NA
1RM
18%
T-test
3.30%
0.85 = -
Moderate
Harris et
al (13)
42
Male
Strength
trained
(1RM/BW=1.4)
4x per
week for 4
weeks - 3
Groups -
HF, HP or
COM
HF (n=13)
1RM
9%
9.31m
Shuttle-
1.00%
0.75= -
Moderate
1.25= -Large-
-1.4 = +Large
HP (n=16)
3.50%
1.70%
COM
(n=13)
10.50%
-2.30%
McBride
et al (24)
26
Male
Recreationally
strength
trained (2-4
years)
8 weeks,
13.5
sessions
of JS
training
JS30%1RM
1RM
7%
T-test
-1.70%
-1.19=
+Moderate
-1.3= +Large
JS80%1RM
10%
-2.30%
Hoffman
et al (18)
20
Male
NCAA Div 3
Gridiron
players
4x /week
for 15
weeks
OL (n=10)
1RM/BM
12%
T-test
-1.60%
-0.34= +Small
PL (n=10)
11%
-2.00%
-0.5= +Small
Hoffman
et al (19)
47
Male
NCAA Division
3 Gridiron
players
15 week
off season
strength
program
C (n=16)
1RM/BM
12%
T-test
-2%
-0.61=
+Moderate
-0.18= +Trivial
CE (n=15)
17%
-1.80%
Keiner et
al(22)
112
Male
Elite junior
soccer players
at professional
clubs
2 years of
periodized
S&C
A-U19
1RM/BM
88.89%
L5
-7.59%
-1.61 = +Large
R5
-4.44%
-1.617=
+Large
FRONT
1RM/BM
87.50%
L10
-5.37%
-1.912 =
+Large
R10
-5.93%
-2.732 = +Very
large
B-U17
1RM/BM
100.00%
L5
-5.80%
-2.102 = +Very
large
R5
-4.72%
-1.151 =
+Moderate
FRONT
1RM/BM
100.00%
L10
-3.90%
-1.103 =
+Moderate
R10
-5.60%
-1.673=
+Large
C-U15
1RM/BM
225.00%
L5
-8.93%
-1.747 =
+Large
R5
-6.83%
-1.595 =
+Large
FRONT
1RM/BM
300.00%
L10
-8.11%
-1.711 =
+Large
R10
-7.38%
-1.977 =
+Large
Tricoli et
al (34)
32
Male
College
physical
education
students
3x per
week for 8
weeks of
VJT or OL
OL (n=12)
HS 1RM
44%
Novel
CODS
test
-2.80%
-1.46 =
+Large
VJT (n=12)
48%
-3.60%
-0.83 =
+Moderate
CT (n=8)
6%
-2.60%
-0.7=
+Moderate
Nimphius,
McGuigan
and
Newton
(27)
10
Female
Elite softball
players
20 weeks
periodized
S&C
NA
Predicted
1RM/BM
12%
505 - D
-1.09%
-0.43= +Small
505 -
ND
-5.48%
-0.81 =
Moderate
n= sample size, 1RM = 1 repetition maximum back squat, BW= bodyweight, NC= not calculated, NA= not available HF= high force, HP= high
power, COM= combined, NCAA= national collegiate athletic association, OL= Olympic lifting, PL= power lifting, NS = not significant, C =
concentric only jump squats, CE= concentric & eccentric jump squats, L=left COD, 5=5m total distance, R= right COD, 10=10m total distance,
RJS= jump squats, VJT = vertical jump training, VB= volleyball, wk=week,
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DISCUSSION
Biomechanics of a Change of Direction
The first segment of the discussion aimed to outline the basic biomechanics involved in a change of direction. Using
Newtonian law some fundamental principles have been applied that determine the factors leading to superior CODS.
First and foremost the laws of motion dictate that the acceleration seen in movement is dependent on the force applied
and the mass of the object that is overcoming it’s inertia (acceleration=force / mass) (12). Any change of direction
involves some aspect of deceleration and acceleration in changing the athlete’s momentum, so force needs to be
produced with the required magnitude to cause the deceleration and acceleration involved in the movement. Of vital
importance in the understanding of velocity is that it doesn’t simply encompass the speed of movement but also a
specific direction. In the majority of sporting environments the desired velocity occurs across a horizontal plane to gain
positional advantage. It has been concluded then that training methods to improve CODS should focus on movements
that occur in the horizontal plane. Unfortunately though this approach is a little short sighted in the approach to the
problem of optimizing CODS training. This is due to the fact that movement through a horizontal plane, using horizontal
force, is determined by vertical force. Frictional force makes up the horizontal component of the resultant vector in a
change of direction (depicted in figure 2) which is determined by the product of the normal reaction force and the
coefficient of friction between the two surfaces in contact with each other (12). Normal reaction force is synonymous
with the vertical force applied to the two surfaces that are in contact. So barring a change of surface or footwear, the
vertical force limits the horizontal force applied in a change of direction and as such the training of vertical force should
be a priority in CODS training. Based on these laws of motion, traditional strength training programs that improve
maximal relative strength in a vertical direction will lead to improvements in vertical force and improve CODS.
Figure 2 Force components in a COD.
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Evidence for the Need to Train Vertical Force Application
Although the basic physics described above supports the efficacy of traditional strength training to improve CODS,
further evidence in a practical setting is required. The first piece of evidence for this was shown by Barnes et al. (3)
who examined the kinetics of a CODS task and found that the vertical component of the resultant vector accounted for
the vast majority of force produced during a change of direction. More evidence of the need for vertical force application
was found by Shimokochi et al (31) who investigated CODS in a lateral plane. This study showed that higher hip
extension velocity (vertical) and lower hip abduction (horizontal) velocity led to faster lateral cutting speed. Finally, in a
lab based setting that is discussed in detail later in the review, Spiteri et al (32) found significantly faster cutting velocities
and significantly higher impulse and force levels in the strongest 50% of their subject pool in comparison to the weakest
50%.
While there have been a number of training studies (7, 8, 13, 18, 19, 24, 27, 34) that have examined strength training
and its influence on CODS, a recent study by Keiner et al (22) established the strongest level of evidence to support the
need for training maximal relative strength in the vertical plane. The CODS and strength capacities of 112 junior soccer
players from the training centres of professional clubs were assessed pre and post a two year training period. The
sample was split into a strength-training group and a control group with sub-cohorts for a variety of age groups (U15,
U17 and U19). Both groups completed 3-4 skill based training sessions per week but in addition the strength group
also completed two sessions of periodised strength training that focussed on the front and back squat. At the end of
the training period the strength-training group had increased their relative strength as measured by the front and back
squats by just over 150% from pretesting levels. With this substantial increase in strength they were shown to be
significantly faster than the control group in the novel CODS test used in the study. This was seen across all age
dependent sub-cohorts used in the study. Finally, the strength-training group also showed much better acceleration
abilities, as they were between 5 and 10% faster in their 10m-sprint time. To date there has been no other training
studies investigating the determinants of CODS with such a large sample size, with a control group and conducted over
a training period of this length. Given the superior methodology used and the resoundingly strong results produced, it
was concluded that training to improve maximal relative strength in a vertical direction should be a primary focus in any
program designed to improve CODS performance.
An argument could be made that this study was completed with developmental athletes who have a large window for
adaptation and natural maturation could have accounted for most of the improvement seen. However justification for
the effectiveness of traditional strength training programs was provided by Nimphius, McGuigan and Newton (27) who
tracked the changes in maximal relative strength and CODS in a group of senior elite softball athletes across a 20 week
preparation period. From pre to post testing the athletes experienced just over a 10% increase in their maximal relative
strength, while also experiencing a concurrent reduction in their 505 CODS test on their dominant (3.57%) and non -
dominant (6.01%) limbs. The athlete’s also improved in a sprint to second base (3.37%), which involves a sport specific
change of direction during the rounding of first base.
Given that significant and positive results were produced in an elite population it was concluded that traditional strength
training aimed at increasing maximal relative strength is an effective methodology to improve CODS.
Table 3 Variety of CODS tests used in the literature.
Test Name
Number of CODS
Movements
Approximate
Duration From
Literature (s)
Target Time for
Elite Athletes (s)
Total Distance (m)
T-test
5
9-12
<9.5
18.28
5-0-5
2
2.5-3
<2.4
30
10m Shuttle
2
2.6-3.2
<2.7
10
8m Sprint with
Single COD
2
1.65-2
<1.7
8
8m Sprint with
Multiple COD
4
2.85
<2.7
8
L-Run
4
5.6-6.5
<5.6
20
Pro-Agility
3
4.6-5.2
<4.7
20
Novel CODS Test #1
(Barnes)
5
5.9-6.3
<5.91
20
Novel CODS Test #2
(Keiner)
4
3.2-3.5
<3.2
15
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Methodological Issues in CODS Testing
The results of the studies discussed provided very strong evidence for the positive role that maximal relative strength
plays in superior CODS. However other investigations have not shown the same results in both correlational (21, 35)
and training studies (8, 13). These studies showed weak relationships and decreases in CODS performance
respectively. A major issue in the CODS literature has been the vast array of CODS tests used, of which an incomplete
list has been provided in table 3. With such a wide variety of tests being used, it becomes exceptionally difficult to
compare between studies. Effective comparison cannot be completed because each test has a different number of
velocity changes, with various distances to cover and duration in time. To remove this issue it is proposed that a lab -
based gold standard is determined to promote more valid and reliable testing in the future.
A recent study by Spiteri, et. al (32) used a novel but highly specific CODS test in a lab based setting. In this study the
authors used infrared timing gates, force plates and the Vicon motion analysis system to record the kinematics and
kinetics of a single 45° change of direction. To begin the test the athletes broke the beam of the first light gate and
accelerated in a straight line over 6 metres toward the force plates, which had been laid at ground level.
When the subjects reached the force plates they were required to have been travelling at a standardised velocity of
4.5m/s ± 0.5 and then perform a cutting movement at 45° to either side and sprint towards the finishing light gate, which
was located 2 meters from the centre of the force plate. A detailed diagram of the protocol set up has been provided in
figure 3. Controlling the approach velocity was of vital importance as any differences seen in the subjects kinetic data
could be attributed solely to their CODS abilities and not their initial velocity. A range of variables were reported and
discussed in this study but the post stride velocity appeared to be a novel and valid assessment of CODS. The velocity
was recorded as the speed of the centre of gravity of the subject at the time of heel strike of the contralateral leg post
the cutting movement (10). This testing protocol has been the most specific and valid assessment of CODS conducted
in the available research and provides the most valuable insight into the determinants of this quality.
Figure 3 CODS test apparatus set up (32).
Methodological Issues in CODS Research - Maximal Strength Tests
The last point of discussion in this brief review was centered on the strength testing protocols used in CODS research.
First and foremost the strength protocol needs to involve the full kinetic chain. Hewitt, et al (14-17) completed four
extensive studies on the kinematics used in a range of common change of direction movements. These studies showed
undoubtedly that CODS requires a high level of skill and motor control to complete the complex task of realigning and
accelerating the entire body. As such single joint testing methods do not take into account the global strength required
to maintain posture and align the major propulsive joints during a change of direction. Therefore the strength tests used
when investigating CODS needs to use a closed kinetic chain assessment involving the ankle, knee and hip with a
concurrent demand on maintaining a rigid trunk.
Secondly, the strength data used for analysis needs to be converted to a value that is relative to the bodyweight o f the
subject. This is a fundamental requirement as the acceleration required in a change of direction is dependent on both
the force generating capacity of the athlete and their body mass, which they are required to move. For example,
Chaouachi et, al. (6) assessed the correlational relationship between maximal strength, using a 1 repetition maximum
half squat, and CODS, using the time achieved in the t-test. Unfortunately the authors failed to convert the absolute
load to a value relative to the bodyweight of the subject. As such the correlational relationship was very low, 0.18 and
did not reach significance (p=0.29). In contrast seven similar studies have seen a moderate to strong inverse
Journal of Australian Strength and Conditioning
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correlational relationship (1, 3, 21, 22, 25, 26, 28, 32) when using a relative strength measure. These relationships
ranged between -0.37 and -0.95 suggesting that the methodology and subjects used in the study will have significant
effect on the strength of this relationship. However it should be noted that an interesting result was produced in the
study by Hori et, al. (21). In the results of this study the authors saw a much stronger relationship for CODS with the
absolute measure of strength (-0.51) in comparison to using the relative measure (-0.37). Given that the mean load
being lifted in this study was approximately 100kg it could be speculated that there is a minimum threshold required for
absolute strength levels before the relative amount starts to dictate performance outcomes more effectively. In
conclusion though it was decided that it was of vital importance to use a closed kinetic chain strength test and to convert
the result to a score that is relative to the athlete’s bodyweight when testing for CODS ability.
CONCLUSIONS AND PRACTICAL APPLICATIONS
There are a wide variety of factors that play a substantial role in CODS that weren’t discussed in this brief review
including unilateral strength (1), eccentric strength, reactive strength and the need for concurrent and specific CODS
training. However considering the time constraints that are often imposed on an S&C coach to develop the physical
qualities required for athletic success it is vital that the available time is used effectively and efficiently. Time cannot be
wasted on ineffective training methods that will not lead to a tangible improvement in an athlete’s performance. The
qualitative analysis of the studies outlined in this review clearly showed that maximal strength, relative to bodyweight,
plays a substantial role in the athlete’s ability to change direction quickly. The review did however fall short of confirming
this with quantitative evidence that takes into account data from all of the available studies so that it can be determined
exactly how much influence strength has on CODS. As such there currently exists a need for an extensive meta-
analysis that quantifies statistically all of the current studies on CODS and strength.
Before concluding it must be reiterated that while the strength and conditioning coach is charged with the task of
providing significant improvements in an athlete’s CODS, there is no guarantee that this will lead to an increase in an
athlete’s sport specific agility. Team sports are highly skill dependent endeavours and while physical superiority needs
to be chased relentlessly, the priority still remains the skill component of their training, as agility is primarily dependent
on cognitive factors including perceptual abilities and decision-making.
In conclusion this brief review has outlined how traditional strength training methods that improve the athlete’s capacity
to produce vertical force will have a positive effect on their CODS. As such it is proposed that strength-training
interventions aimed at developing maximal relative strength should be implemented with all athletes whose sport
demands regular and rapid changes of direction.
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3. Barnes, J. L., Schilling, B. K., Falvo, M. J., Weiss, L. W., Creasy, A.
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... Collectively, co-contraction of the knee flexors and extensors is required to tolerate the large external loads at the knee when changing direction [51]. As such, due to the greater muscle activations of the knee flexors and extensors during sharper CODs, practitioners should aim to develop knee flexor and extensor strength, in particular eccentric strength [41,58,81,98,[105][106][107][108][109], in athletic populations where CODs are fundamental movements. This may assist and facilitate a greater capacity to absorb the high forces [19,25,27,29] and tolerate the greater knee joint loading [22,[27][28][29][30] associated during the deceleration phases of CODs. ...
... This may assist and facilitate a greater capacity to absorb the high forces [19,25,27,29] and tolerate the greater knee joint loading [22,[27][28][29][30] associated during the deceleration phases of CODs. Furthermore, improvements in strength capacity may improve an athlete's ability to produce greater braking and propulsive forces and impulse [41,81,107,110], which are determinants of faster performance [41,59,60,106], thus positively enhancing COD performance. ...
... Athletes should ideally possess a solid foundation of strength (one repetition maximum back squat ≥ 1.5 × body mass) before performing complex and higher intensity plyometrics [81,101,118], while eccentric strength capacity is also fundamental for successful COD performance and tolerating the large joint loading [41,58,81,98,[105][106][107][108][109]. Shorter GCTs have been identified as determinants of faster COD performance [40,42,59,112]; thus, the aims of the aforementioned training recommendations are to reduce braking and propulsive force duration (total duration), but simultaneously increase braking and propulsive forces, resulting in a tall and thin impulse, in contrast to a short and wide impulse. ...
Article
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Changes of direction (CODs) are key manoeuvres linked to decisive moments in sport and are also key actions associated with lower limb injuries. During sport athletes perform a diverse range of CODs, from various approach velocities and angles, thus the ability to change direction safely and quickly is of great interest. To our knowledge, a comprehensive review examining the influence of angle and velocity on change of direction (COD) biomechanics does not exist. Findings of previous research indicate the biomechanical demands of CODs are ‘angle’ and ‘velocity’ dependent and are both critical factors that affect the technical execution of directional changes, deceleration and reacceleration requirements, knee joint loading, and lower limb muscle activity. Thus, these two factors regulate the progression and regression in COD intensity. Specifically, faster and sharper CODs elevate the relative risk of injury due to the greater associative knee joint loading; however, faster and sharper directional changes are key manoeuvres for successful performance in multidirectional sport, which subsequently creates a ‘performance-injury conflict’ for practitioners and athletes. This conflict, however, may be mediated by an athlete’s physical capacity (i.e. ability to rapidly produce force and neuromuscular control). Furthermore, an ‘angle-velocity trade-off’ exists during CODs, whereby faster approaches compromise the execution of the intended COD; this is influenced by an athlete’s physical capacity. Therefore, practitioners and researchers should acknowledge and understand the implications of angle and velocity on COD biomechanics when: (1) interpreting biomechanical research; (2) coaching COD technique; (3) designing and prescribing COD training and injury reduction programs; (4) conditioning athletes to tolerate the physical demands of directional changes; (5) screening COD technique; and (6) progressing and regressing COD intensity, specifically when working with novice or previously injured athletes rehabilitating from an injury.
... In light of these determinants, coaches and practitioners should seek to develop their athletes' physical qualities (e.g. concentric, reactive, isometric, eccentric strength, rate of force development) and ability to rapidly produce and accept force (time limited forceexpression), across the whole force-velocity spectrum (10,21,24,75,108). Improving these physical qualities has been shown to positively enhance COD speed and agility performance (10,21,50,75,76,99,108), but will also be beneficial in reducing injury risk and promoting safer mechanics (21,51,70,75,80,99). ...
... concentric, reactive, isometric, eccentric strength, rate of force development) and ability to rapidly produce and accept force (time limited forceexpression), across the whole force-velocity spectrum (10,21,24,75,108). Improving these physical qualities has been shown to positively enhance COD speed and agility performance (10,21,50,75,76,99,108), but will also be beneficial in reducing injury risk and promoting safer mechanics (21,51,70,75,80,99). It is beyond the scope of this article to provide specific resistance training and plyometric training guidelines for COD and as such, readers are directed to the excellent recommendations provided in previous reviews and chapters (10,21,24,75,108). ...
... Improving these physical qualities has been shown to positively enhance COD speed and agility performance (10,21,50,75,76,99,108), but will also be beneficial in reducing injury risk and promoting safer mechanics (21,51,70,75,80,99). It is beyond the scope of this article to provide specific resistance training and plyometric training guidelines for COD and as such, readers are directed to the excellent recommendations provided in previous reviews and chapters (10,21,24,75,108). The following section will focus on the coaching and delivery of cutting COD speed and agility training by providing technical guidelines and verbal cues for coaching faster and safer cutting (i.e. ...
Article
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Abstract Cutting actions are important maneuvers in multidirectional sport and are also key actions associated with non-contact anterior cruciate ligament injury; however, it is important to note that three primary cutting techniques have been studied within the literature: the side-step, crossover cut, and split-step. These cutting techniques demonstrate kinetic and kinematic differences which have distinct implications for both performance and potential injury risk. In this review, we discuss the advantages and disadvantages of the three cutting techniques and provide cutting technical guidelines, verbal coaching cues, and change of direction speed and agility programming recommendations to enhance performance and promote safer mechanics.
... Many studies have investigated the effects of different physical training forms on COD ability and COD as a phenomenon [4,[12][13][14][15][16]. Most studies generalized COD as one discrete ability, while not accounting for the specificity that different COD tasks represent [4,13,17]. ...
Article
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The purpose of this study was to compare how 6 weeks of strength-vs. plyometric training, which were matched upon direction of motion and workload, influences change of direction (COD) performance. Twenty-one experienced male soccer players (age: 22.2 ± 2.7) were pair-matched into a strength-(n = 10) and a plyometric (n = 11) training group. CODs of 45 • , 90 • , 135 • and 180 • performed from either a 4 m or 20 m approach distance were compared before and after intervention. Results showed no significant difference between groups. Significant effects were only found within the plyometric training group (−3.2% to −4.6%) in 90 • , 135 • and 180 • CODs from 4 m and a 180 • COD from a 20 m approach distance. Individual changes in COD performances showed that with the 4 m approach at least 55% and 81% of the strength and plyometric training group, respectively, improved COD performance, while with the 20 m approach at least 66% of both groups improved performance. This study showed that the plyometric training program can improve most CODs, with angles over 90 • , although this is dependent on the distance approaching the COD. Considering the limited time of implementing physical conditioning, in addition to regular soccer practice in most soccer environments, the current plyometric training program can be advantageous in improving CODs at maximal intensity.
... Discrepancies on the precise definition of CODs are however encountered in sport science literature [5]. Traditional definitions described CODs as an ability to quickly change direction in running, while more recent studies defined it as the capability of accurate change in direction [6][7][8]. ...
Article
Full-text available
Change of direction speed is globally assessed through temporal measurements. The underlying biomechanical mechanisms affecting Change of direction speed performance, however, could not be fully understood using performance duration. A more precise biomechanical analysis of change of direction speed performance in different phases of movement, including the deceleration, turning maneuver and reacceleration could cast a light on the importance of each phase during movement. This study investigated a new approach to Change of direction speed drill analyses using three factors of the radius of curvature, accuracy and speed. Twenty-four collegiate athletes (Age: 21.67±2.29years, Height: 1.79±0.07m, body mass: 71.38±3.12Kg) performed 6 trials of 5-0-5 Change of direction speed test with both dominant (n=3) and non-dominant (n=3) legs at the turning point. Paired sample T-test was run to determine the differences between biomechanical characteristics of the center of mass, such as radius of curvature (Rc), deviation, length and speed, as well as the performance time in both dominant and non-dominant legs. Data acquisition took place using 6 optoelectronic cameras (Vicon motion capture system – 240Hz). Outcomes indicated that the time difference between dominant and non-dominant leg performances was negligible; however, measurements of distances travelled and the associated speeds were significantly higher with non-dominant legs (p≤0.01). Rc and deviation were also higher in non-dominant legs (p≤0.03). It was shown that when the Change of direction speed was approached using the non-dominant leg, athletes performed the test with higher velocities and utilized more muscular engagements to compensate deficits in their performance. Measurements of time for drill duration however, failed to reveal such performance characteristics.
... Although several studies have shown mixed training programmes and neuromuscular training appear to be ineffective in addressing COD biomechanics associated with increased ACL loading and potential non-contact injury risk (Tables 3 and 4), these training modalities have been shown to be effective in reducing ACL injury rates [1,89,94,120] and may improve other qualities such as strength, muscle activation and athletic performance [1,94]. Similarly, resistance training appears to be ineffective for reducing COD knee joint loads; however, this training modality elicits positive performance adaptations [97, 105,123,124] and is considered important for athletes to tolerate the loading associated when changing direction [19,55,94,97,100,101]. Therefore, mixed training programmes, injury-prevention neuromuscular warm-ups and resistance training should not be overlooked, and warrant inclusion into an athlete's holistic training programme. ...
Article
Full-text available
Change of direction (COD) manoeuvres are associated with anterior cruciate ligament (ACL) injury risk due to the propensity to generate large multiplanar knee joint loads. Given the short- and long-term consequences of ACL injury, practitioners are interested in methods that reduce knee joint loads and subsequent ACL loading. An effective strategy to reduce ACL loading is modifying an athlete’s movement mechanics to reduce knee joint loading. The purpose of this scoping review was to critically appraise and comprehensively synthesise the existing literature related to the effects of training interventions on COD biomechanics associated with increased knee joint loads and subsequent ACL loading, and identify gaps and recommend areas for future research. A review of the literature was conducted using Medline and Sport DISCUS databases. Inclusion criteria consisted of pre-post analysis of a COD task, a minimum 4-week training intervention, and assessments of biomechanical characteristics associated with increased ACL loading. Of the 1,027 articles identified, 22 were included in the scoping review. Based on current literature, balance training and COD technique modification are the most effective training modalities for reducing knee joint loading (small to moderate effect sizes). One study reported dynamic core stability training was effective in reducing knee joint loads, but further research is needed to definitively confirm the efficacy of this method. Perturbation-enhanced plyometric training, the F-MARC 11 + soccer specific warm-up, Oslo Neuromuscular warm-up, and resistance training are ineffective training modalities to reduce COD knee joint loads. Conflicting findings have been observed for the Core-Pac and mixed training programme. Consequently, practitioners should consider incorporating balance and COD technique modification drills into their athletes’ training programmes to reduce potentially hazardous knee joint loads when changing direction. However, training intervention studies can be improved by investigating larger sample sizes (> 20), including a control group, acknowledging measurement error when interpreting their findings, and considering performance implications, to confirm the effectiveness of training interventions and improve adherence.
... Lower-limb strength and rapid force production qualities have been identified as physical qualities associated with COD speed performance [19,29,33,58,59], which is unsurprising because braking and propulsive forces are associated with faster COD speed performance [53,60,61]. Spiteri et al. [56] compared offensive agility between sexes and found male athletes demonstrated greater isometric strength, greater braking and propulsive forces and impulses (p = 0.010, Effect size (ES) = 1. ...
Article
Full-text available
The purpose of this study was twofold: (1) to examine differences in change of direction (COD) performance and asymmetries between team-sports while considering the effects of sex and sport; (2) to evaluate the relationship between linear speed, COD completion time, and COD deficit. A total of 115 (56 males, 59 females) athletes active in cricket, soccer, netball, and basketball performed the 505 for both left and right limbs and a 10-m sprint test. All team-sports displayed directional dominance (i.e., faster turning performance/shorter COD deficits towards a direction) (p ≤ 0.001, g = −0.62 to −0.96, −11.0% to −28.4%) with, male cricketers tending to demonstrate the greatest COD deficit asymmetries between directions compared to other team-sports (28.4 ± 26.5%, g = 0.19-0.85), while female netballers displayed the lowest asymmetries (11.0 ± 10.1%, g = 0.14-0.86). Differences in sprint and COD performance were observed between sexes and sports, with males demonstrating faster 10-m sprint times, and 505 times compared to females of the same sport. Male soccer and male cricketers displayed shorter COD deficits compared to females of the same sport; however, female court athletes demonstrated shorter COD deficits compared to male court athletes. Large significant associations (ρ = 0.631-0.643, p < 0.001) between 505 time and COD deficit were revealed, while trivial, non-significant associations (ρ ≤ −0.094, p ≥ 0.320) between COD deficit and 10-m sprint times were observed. In conclusion, male and female team-sport athletes display significant asymmetries and directional dominance during a high approach velocity 180° turning task. Coaches and practitioners are advised to apply the COD deficit for a more isolated measure of COD ability (i.e., not biased towards athletes with superior acceleration and linear speed) and perform COD speed assessments from both directions to establish directional dominance and create a COD symmetry profile.
... Several investigations have reported the association between strength measures, such as one-repetition maximum (1-RM), and performance in various change of direction (COD) assessments [10,[15][16][17]. Accordingly, recent studies have demonstrated strength training to be effective for enhancing performance in COD tasks [4,[18][19][20]. ...
Article
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This study investigated the effects of eccentric phase-emphasis strength training (EPE) on unilateral strength and performance in 180- and 45-degree change of direction (COD) tasks in rugby union players. A 12-week cross-over design was used to compare the efficacy of resistance training executed with 3 s eccentric duration (EPE, n = 12) against conventional strength training, with no constraints on tempo (CON, n = 6). Players in each condition were categorised as ‘fast’ (FAST) or ‘slow’ (SLOW) using median trial times from baseline testing. Players recorded greater isometric strength improvements following EPE (ES = −0.54 to 1.80). Whilst these changes were not immediate, players improved in strength following cessation. Improvements in 180-degree COD performance was recorded at all test-points following EPE (ES = −1.32 to −0.15). Improvements in 45-degree COD performance were apparent for FAST following CON (ES = −0.96 to 0.10), but CON was deleterious for SLOW (ES = −0.60 to 1.53). Eccentric phase-emphasis strength training shows potential for sustained strength enhancement. Positive performance changes in COD tasks were category- and condition-specific. The data indicate the greatest improvement occurred at nine weeks following resistance training in these players. Performance benefits may also be specific to COD task, player category, and relative to emphasis on eccentric phase activity.
Article
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The change of direction (COD) ability is a task-specific skill dependent on different factorssuch as the degree of the turn, which has led to differentiating CODs as more force- (>90◦) or velocity-oriented (<90◦). Considering force and velocity requirements is of importance when designingsport-specific training programs for enhancing COD performance. Thus, 25 female handball andsoccer players participated in this study, which investigated the association between three differentstrength and plyometric exercises and force- and velocity-oriented COD performance. By utilizingthe median split analysis, the participants were further divided into a fast (n= 8) and a slow (n= 8)COD group, to investigate differences in step kinematics between fast and slow performers. Thecorrelational analysis revealed that the bilateral back squat and unilateral quarter squat were signifi-cantly associated with several force- and velocity-oriented COD performance (r=−0.46 to−0.64),while the association between plyometric and COD performance was limited (r <0.44). The fastCOD group revealed higher levels of strength, jump height, peak velocities, higher step frequencies,shorter ground contact times, and greater acceleration and braking power (d> 1.29,p< 0.03). It wasconcluded that the observed correlation between strength and COD performance might be due tostronger athletes being able to produce more workload in a shorter time, which was supported bythe step kinematics.
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The purpose of the present study was to develop an effective testing battery for female field hockey by using anthropometric, physiological, and skill-related tests to distinguish between regional representative (Rep, n = 35) and local club level (Club, n = 39)female field hockey players. Rep players were significantly leaner and recorded faster times for the 10-m and 40-m sprints as well as the Illinois Agility Run (with and without dribbling a hockey ball). Rep players also had greater aerobic and lower body muscular power and were more accurate in the shooting accuracy test, p < 0.05. No significant differences between groups were evident for height, body mass, speed decrement in 6 X 40-m repeated sprints, hand-grip strength, or pushing speed. These results indicate that %BF sprinting speed, agility, dribbling control, aerobic and muscular power, and shooting accuracy can distinguish between female field hockey players of varying standards. Therefore talent identification programs for female field hockey should include assessments of these physical parameters.
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Objectives To determine (1) correlations between isokinetic lower extremity strength and functional performance and (2) correlations among different modes of isokinetic testing. Design and Setting A correlational design with 6 measures. A series of strength, power, and agility tests was performed at a hospital-based outpatient physical therapy clinic. Participants A volunteer sample of 29 male and 31 female, college-age subjects participated. Measurements All subjects were tested in the following isokinetic tests: reciprocal leg press, single-leg squat, and knee extension. Performance tests included single-leg hop and vertical jump and a speed/agility test. Results Analysis showed isokinetic knee extension, leg press, and single-leg squat strength significantly correlated to all functional tests. There were significant correlations among the 3 different isokinetic strength measures, as well. Conclusions These results suggest a significant relationship between lower extremity open and closed chain isokinetic strength and functional performance testing.
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This study aimed to identify the key technical features that are consistently present in superior 180° ground-based change of direction performances (180gbCOD), but lacking in lesser skilled performances. Twenty-two national under 21 level netball players performed three trials of a 180° turn from a static start, followed by a 2.5 m straight sprint. High-speed video of the movement was recorded for each trial. A qualitative analytic approach was used to analyze the technical strategies employed by players throughout the movement task. Five key technical features were identified that were consistently observed in superior 180gbCOD performances (first foot ground contact was parallel to the new direction): 1) shallow squat combined with backward-moving centre of mass; 2) head leading the body through the turn; 3) arms and legs close to the body through the turn; 4) full extension of the takeoff leg (trail leg) at first takeoff; and, 5) large takeoff distance (distance from the foot of the trail leg to the center of mass) at first takeoff. These features provide coaches with valuable insight into the technical cues that appear to contribute to a superior 180gbCOD performance.
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Prior to improving the strength/power qualities associated with a movement, strength and conditioning coaches need to first understand the mechanics of the movement via some sort of movement analysis. The purpose of this study was to determine the key technical features associated with a 180° aerial change of direction (aCOD) performance. The aCOD task involved catching a suspended ball while turning 180° in the air and was recorded using high-speed video. Thirty seven netball players (5 elite, 32 sub-elite) were grouped into three categories (Superior, Average and Below Average) based on the effectiveness of their landing (a complete 180° rotation with a two-foot landing). Seven key technical features were consistently observed in the superior aCOD performances: 1) sinking into a deep hip and knee flexion (~135°) through the final ground contact in the approach; 2) rotating about the takeoff leg prior to leaving the ground; 3) driving both arms up towards the ball, no more than shoulder width apart; 4) driving the free leg up towards the ball at takeoff; 5) following possession of the ball, rapidly rotating the head into the new direction; 6) holding the ball close to the body at chest height once possession had been made in preparation for a quick release pass; and, 7) rapid rotation of the lower body throughout the airborne phase to elicit a full 180° turn. This type of analysis provides focus for programming of the appropriate musculature and technical cues for coaching the movement of interest.
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Abstract Understanding the magnitude of forces and lower body kinematics that occur during a change of direction (COD) task can provide information about the biomechanical demands required to improve performance. To compare the magnitude of force, impulse, lower body kinematics and post-COD stride velocity produced between athletes of different strength levels during a COD task, 12 stronger (8 males, 4 females) and 12 weaker (4 males, 8 females) recreational team sport athletes were recruited. Strength levels were determined by relative peak isometric force of the dominant and non-dominant leg. All athletes performed 10 pre-planned 45° changes of direction (5 left, 5 right) while three-dimensional motion and ground reaction force (GRF) data were collected. Differences in all variables for the dominant leg were examined using a one-way analysis of variance (ANOVA) with a level of significance set at p ≤0.05. The stronger group displayed significantly faster post-COD stride velocity and greater vertical and horizontal braking forces, vertical propulsive force, vertical braking impulse, horizontal propulsive impulse, angle of peak braking force application, hip abduction and knee flexion angle compared to the weaker group. The results suggest that individuals with greater relative lower body strength produced higher magnitude plant foot kinetics and modified lower body positioning while producing faster COD performances. Future investigations should determine if strength training to enable athletes to increase plant foot kinetics while maintaining or adopting a lower body position results in a concomitant increases in post-COD stride velocity.
Article
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The requirement profiles of sports such as soccer, football, tennis and rugby demonstrate the importance of strength and speed-strength abilities, in addition to other conditional characteristics. During a game, these athletes complete a large number of strength and speed-strength actions. In addition to the linear sprint, athletes perform sprints while changing direction (COD). Therefore, this study aims to clarify the extent to which there is a strength-training intervention effect on COD. Further, this investigation analyzes possible correlations between the One Repetition Maximum / Body Mass (SREL) in the front and back squat and COD. The subjects (n = 112) were at pretest between 13 and 18 years old and were divided into two groups with four subgroups (A = under 19-years-old, B = under 17-years-old, C = under 15-years-old). For approximately 2 years, one group (CG) only participated in routine soccer training, and the other group (STG) participated in an additional strength-training program with the routine soccer training. Additionally, the performances in COD of 34 professional soccer player of the 1st and 2nd division in Germany were measured as a standard of high-level COD. For the analysis of the performance development within a group and pairwise comparisons between two groups, an analysis of variance with repeated measures was calculated with the factors group and time. Relationships between COD and SREL were calculated for the normal distributed data using a plurality of bivariate correlations by Pearson. Our data show that additional strength training over a period of 2 years significantly affects the performance in COD. The STG in all subcohorts reached significantly (p < 0.05) faster times in COD than CG. The STG amounted up to 5% to nearly 10% better improvements in the 10 meter sprint times compared to the CG. Furthermore, our data show significant (p < 0.05) moderate to high correlations (r = -0.388 to -0.697) between SREL and COD. Our data show that a long-term strength training improve the performance of the COD. Therefore, a long-term resistance training is recommended as early as childhood and adolescence.
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Traditional weight training programs utilize an exercise prescription strategy that emphasizes improving muscle strength through resistance exercises. Other factors, such as stability, endurance, movement quality, power, flexibility, speed, and agility are also essential elements to improving overall functional performance. Therefore, exercises that incorporate these additional elements may be beneficial additions to traditional resistance training programs. The purpose of the study was to compare the effects of an isolated resistance training program (ISO) and an integrated training program (INT) on movement quality, vertical jump height, agility, muscle strength / endurance, and flexibility. The ISO program consisted of primarily upper and lower extremity progressive resistance exercises. The INT program involved progressive resistance exercises, as well as core stability, power, and agility exercises. Thirty subjects were cluster-randomized to either the ISO (n=15) or INT (n=15) training program. Each training group performed their respective programs 2-times per week for 8 weeks. Subjects were assessed before (pre-test) and after (post-test) the intervention period using the following assessments: a jump-landing task graded using the Landing Error Scoring System (LESS), vertical jump height, T-test time, push-up and sit-up performance, and sit-and-reach test. The INT group performed better on the LESS test (pre-test: 3.90±1.02, post-test: 3.03±1.02; P=0.02), faster on the T-test (pre-test: 10.35±1.20s, post-test: 9.58±1.02s; P=0.01), and completed more sit-ups (pre-test: 40.20±15.01, post-test: 46.73±14.03; P=0.045) and push-ups (pre-test: 40.67±13.85, post-test: 48.93±15.17, P=0.05) at post-test compared to pre-test, and compared to the ISO group at post-test. Both groups performed more push-ups (P=0.002), jumped higher (P<0.001), and reached further (P=0.008) at post-test compared to pre-test. Performance enhancement programs should use an integrated approach to exercise selection in order to optimize performance and movement technique benefits.
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Basketball players have to move laterally and quickly change their movement directions, especially during defensive moves. This study aimed to investigate how frontal and sagittal plane hip movements relate to fastness and quickness of lateral cutting maneuvers from sliding. 3D biomechanical data were obtained for 28 female college basketball players while they performed lateral cutting maneuvers using their left leg after two lateral sliding steps. The lateral cutting index (LCIndex) expressing fastness and quickness of lateral cutting maneuvers, peak hip abduction and extension velocities immediately before foot contact, hip abduction and extension velocities at foot contact, peak horizontal ground reaction force, frontal plane ground reaction force angle, and sacrum center of mass position were calculated. Simple and stepwise regression analyses were both conducted to predict LCIndex. The former showed that greater maximum hip extension velocity (p = 0.03) and lesser hip abduction velocity (p = 0.04) as well as smaller ground reaction force angle (p = 0.001) and lower sacrum center of mass position (p = 0.001) at foot contact led to better LCIndex. The latter showed that sacrum center of mass position at foot contact and hip extension velocity explained 35.3% (p < 0.01) and 7.3% (p = 0.088) of variance in LCIndex, respectively. Our results did not suggest that hip abductor function is important for lateral sliding moves, instead suggesting that faster hip extension motions to kick the ground and lowering the body center of mass are crucial for better lateral deceleration-acceleration motions.