THE EFFECT OF CRYOTHERAPY ON THREE DIMENSIONAL ANKLE
KINEMATICS DURING A SIDESTEP CUTTING MANEUVER
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Department of Kinesiology and Health Promotion, University of Kentucky,
Lexington, KY, USA
| Received |
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02 November 2004 |
| Accepted |
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30
March 2004 |
| Published |
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01
June 2004 |
©
Journal of Sports Science and Medicine (2004) 3, 83-90
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| ABSTRACT |
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Although cryotherapy is commonly used in the treatment of acute and
chronic athletic injuries, the deleterious effects of limb cooling,
such as decreased nerve and muscle function, slowed sensation and
inhibition of normal relaxes, may put an athlete at increased risk
of additional injury. The purpose of this study was to determine the
effects of cryotherapy on subtalar and ankle joint kinematics of healthy
athletes performing a sidestep 45° cut. We hypothesized that greater
joint displacements and velocities would be seen after icing. Twenty
one subjects performed a 45° sidestep cut prior to and after limb
cooling. Retroreflective markers were placed on the subject's shank
and foot while 6 high-speed cameras were used to collect the kinematic
data. In this test-retest controlled laboratory study, a repeated
measures ANOVA was performed on the PRE and POST icing data for the
minimum and maximum joint displacements and velocities. No statistical
differences were noted between the PRE and POST icing conditions.
The results indicate that a 10-minute icing treatment did not have
an effect on either the movement patterns or angular velocities. Our
results do not support any change in practice of icing injured ankles
for ten minutes during halftime of athletic events.
KEY
WORDS: Biomechanics, movement, range of motion, running, musculoskeletal
system.
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| INTRODUCTION |
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Sidestep
cutting movements are common in many sports, including basketball,
soccer, tennis, and volleyball (Stacoff et al. 1996).
This action occurs when a person, in the stance phase of the running
stride, cuts toward the side of the body of the swinging leg. The
sidestep cut maneuver has been called by several names, including
the lateral cut, 'V' cut, open cut, and forward medial cut (McLean
et al., 1999;
Neptune et al., 1999;
Simpson et al., 1999;
Stacoff et al., 1996).
The kinematics of this movement have been studied by several investigators.
Neptune et al. (1999)
investigated the ankle kinematics of a 45° open cut. They reported
minimal motion of the subtalar/ankle joint complex in the frontal
plane, with subjects contacting the ground in approximately 20°
of supination and remaining in this position throughout the stance
phase. In the sagittal plane, subjects struck the ground in approximately
20° of dorsiflexion, plantarflexed until the foot reached a neutral
position at 20% of the stance phase, dorsiflexed to approximately
25° at 70% of the stance phase, and then plantarflexed until toe
off. The type of footwear worn by the subjects, if any, was not
mentioned. In another study, Stacoff et al. (1996)
reported that barefoot subjects struck the ground in a subtalar
joint neutral position, and reached a maximum inversion angle of
approximately 8°.
Ankle sprains account for approximately 20% of the total injuries
sustained during intercollegiate athletics (NCAA, 1991).
Cryotherapy, or icing and/or submersion of the foot and ankle in
cold water, is a very popular treatment method for both acute and
chronic athletic injuries because of its ability to reduce pain,
inflammation, and muscle spasm (Meeusen et al., 1986).
Athletes often receive cryotherapy treatment during the standard
ten-minute period of halftime and then return to the playing field
before the affected limb has the opportunity to return to normal
temperature.
Swenson et al. (1996)
reported few complications or side effects of cryotherapy. However,
it may not be totally advantageous. The athlete may be at increased
risk for additional injury if sensation or movement are affected
by the treatment (Lephart et al., 1997;
1998). Limb cooling
decreases nerve and muscle function, sensation, and slows or inhibits
normal reflexes (Denys, 1991;
Swenson et al., 1996;
Schieppati et al., 1997).
Afferent input from the dynamic stabilizer muscles surrounding the
ankle joint may play a critical role in the prevention of ankle
sprains (Neptune et al., 1999).
If neuromuscular function is compromised by the treatment, the athlete
may be at increased risk of sustaining a subsequent injury on the
limb.
Only one study was found in the literature that has investigated
the effect of cryotherapy on ankle joint biomechanics during functional
activities. Hopper and coworkers (1997)
suggested that the clinical application of cryotherapy is not deleterious
to joint position sense and, assuming normal joint integrity, patients
may resume exercise without the possibility of increased injury.
However, no movement analysis data were reported from this study.
Despite the prevalence of ankle injuries in sports, few studies
have been performed on the kinematics of the ankle during a sidestep
cutting maneuver. Additionally, although cryotherapy is one of the
primary treatments for acute and chronic ankle injury, its effects
on the kinematics of the ankle/subtalar joint complex remain unexplored.
Therefore, the purpose of this study was to determine the effects
of cyrotherapy on ankle/subtalar joint range of motion, displacement
and velocity of healthy athletes performing a 45º sidestep cut maneuver.
The ultimate goal of this study was to provide insight as to whether
or not an athlete is more at risk for sustaining an additional injury
after their ankle has been treated with cryotherapy. We hypothesized
that, after the ten-minute icing treatment, the three dimensional
angular displacements, ranges of motion, and velocities of the foot
with respect to the shank would increase, thereby making the ankle
joint complex less stable than it was before the icing treatment.
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| METHODS |
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Subjects
Twenty-one young healthy subjects who were recreationally active
or intercollegiately competitive participated in the study (14 females
and 7 males, age: 21.6±1.5 yrs, height 170.28±7.9 cm, and mass 69.75±12.1
kg). All subjects were rearfoot strikers. Eight subjects reported
to be right leg dominant and thirteen subjects reported to be left
leg dominant. The dominant leg was defined as the leg that the subject
would choose to kick a ball, making the non-dominant leg the stance
leg during the kick (Wojtys et al., 1996).
The non-dominant leg was chosen as the treatment leg in this study.
None of the subjects had a lower extremity injury during the past
year, nor did any subject report a history of ankle instability
as indicated by a history of frequency ankle sprains. Individuals
were who forefoot strikers were also excluded from the study.
Procedures
Data collection took place in the Biodynamics Laboratory in the
Wenner-Gren Center for Biomedical Engineering on the campus of the
University of Kentucky. After the subject's arrival in the laboratory,
the experimental procedures were explained, and a university-approved
informed consent was signed. The subject's height and weight were
obtained using a calibrated stadiometer and scale (Continental Scale
Corp., Chicago, IL). The subject's standing subtalar joint angle
was obtained according to the method by Palmer and Eppler (1998).
The mean standing subtalar position was 1.69 ± 4.88° of rearfoot
eversion. Each subject warmed up by walking at a self-selected pace
on a treadmill for five to ten minutes. The subject was then instructed
to perform several moderate stretches such as would be done prior
to participation in an athletic event.
In order to analyze body movements, spherical retroreflective markers
were placed on anatomical landmarks on the subject's lower leg and
foot on their non-dominant limb (Figure
1). Markers were placed on the medial and lateral knee joint
lines, and medial and lateral malleoli. A rigid triad of markers
was placed on the lateral shank to define the lower leg. Markers
placed on the head of the third metatarsal and medial and lateral
aspects of the heel defined the foot segment. The markers were attached
to the subject using Red Dot adhesive electrodes (3M Corporation,
St. Paul, Minnesota). Joint movement data were collected with a
6-camera motion analysis system (Motion Analysis Inc., Santa Rosa,
CA) sampling at 120 Hz. The video system accuracy was within ± 0.5º.
Because it was not possible to have each subject wear identical
footwear and because footwear can greatly affect movement of the
ankle and subtalar joint during running, subjects were barefoot
during data collection.
In order to obtain a biomechanical model of the leg and foot, a
static trial was collected with the subject standing in their relaxed
upright stance position. The top of the lower leg was defined as
the point midway between the medial and lateral knee markers. The
point midway between the malleoli markers was defined as the center
of rotation for the ankle and subtalar joints. In other words, flexion
and extension, inversion and eversion, and internal and external
rotation all occurred around a point midway between the malleoli
markers. After the static trial was collected, the knee joint and
malleoli markers were removed from the subject.
Subjects were instructed to run straight forward until their non-dominant
leg struck a Kistler force plate (Winterthur, Switzerland) and then
cut 45º medially toward a target located on their dominant side
(Neptune et al., 1999).
In order to ensure that the subject performed a sidestep cut of
45º, a line of masking tape was placed on the laboratory floor to
act as a guide. Subjects were instructed to perform the above maneuver
as quickly as possible. However, as timing lights were not used,
we were unable to control for running speed. Subjects were given
as many practice runs as they felt necessary to become comfortable
with the maneuver.
Seven pre-treatment trials were collected. An investigator of the
study watched each trial closely to make certain that the subject
performed a sidestep cut of 45º without any visible alteration in
gait mechanics, such as targeting the force plate. Subjects then
underwent the cryotherapy treatment, which consisted of having a
bag of ice placed on the medial and lateral aspects of their non-dominant
ankle for a period of 10 minutes. During the icing treatment, the
retroreflective markers on the medial and lateral heel were removed
from the subject. However, the cloth adhesive backing remained on
the subject in order for the two heel markers to be placed at the
same locations again after the icing. Seven post-treatment trials
were collected immediately after icing. All data collection was
completed by five minutes after the icing treatment.
Data
Analysis
The three dimensional video data were processed and analyzed using
Eva 6.0 and Kin-Trak 6.2 motion analysis software (Motion Analysis,
Inc., Santa Rosa, CA). Coordinate data were smoothed using a fourth
order Butterworth low-pass filter with a cutoff frequency of 6 Hz.
Euler angles of the foot with respect to the shank were calculated
using the following order of rotations: plantarflexion/ dorsiflexion,
internal/external rotation, inversion/ eversion. Maximum sagittal,
frontal, and transverse plane displacements and velocities were
calculated.
The data obtained from the force plate were used to define the stance
phase of the running cycle. Video data were collected for 3 seconds
during each trial. Video data were compared against the force data
to determine the video frame numbers in which foot contact and toe
off occurred. All kinematic data not associated with the stance
phase of the running stride were eliminated.
Our dependent variables were sagittal, frontal, and transverse plane
displacements and velocities. Our independent variable was condition
(i.e. pre and post icing). A repeated measures ANOVA (
= 0.05) was performed on each variable using SPSS 10.0 software
(Chicago, IL).
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| RESULTS |
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Joint
displacement was not affected by the icing treatment. The overall
amount of displacement in the sagittal, frontal, and transverse
planes was not significantly different between the pre and post
icing conditions (Table 1).
The average amounts of peak plantar flexion and dorsiflexion were
4.1 ± 13.5º and 6.4 ± 14.9º, respectively. Subjects displayed an
average peak inversion of 7.5 ± 17.5º, and average peak eversion
of 6.2 ± 14.4º. Transverse plane peak displacements were 7.0 ± 30.7º
of internal rotation and 1.2 ± 30.8º of external rotation. Ranges
of motion for each condition are displayed in Figure
2.
Movement velocity was also not different between the pre and post
icing conditions. Sagittal plane peak plantar flexion velocity was
144.9 ± 316.4º/sec. Average peak dorsiflexion velocity was 160.5
± 282.3º/sec. In the frontal plane, peak inversion and eversion
velocities were 213.2 ± 309.6º/sec and 204.4 ± 339.3º/sec, respectively.
The peak internal rotation velocity was 158.1 ± 214.1º/sec, and
peak external rotation velocity was 164.7 ± 213.1º/sec.
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| DISCUSSION |
The
purpose of this study was to determine the effects of cyrotherapy
on ankle/subtalar joint displacement and velocity of a healthy athlete
performing a 45º sidestep cut maneuver. The results of this study
indicate that a 10-minute icing treatment did not have an effect on
either of these parameters.
A post-hoc analysis of the data revealed that the majority of the
subjects displayed one of two movement patterns. Six subjects utilized
a predominantly sagittal plane movement pattern (Figure
3, Table 2) while eleven
subjects displayed a frontal plane pattern (Figure
4, Table 3). The patterns
of four subjects were unique to themselves. Because of limitations
in statistical power, these patterns may only be discussed qualitatively.
These two patterns were not dependent upon whether the subject contacted
the ground with the heel or the forefoot as all subjects were rearfoot
strikers. Subjects who exhibited a sagittal plane pattern demonstrated
26º of sagittal plane motion during foot contact, whereas their frontal
plane range of motion was 17º. Conversely, subjects who demonstrated
a frontal plane pattern displayed a 30º of subtalar eversion/inversion
range of motion but only 15º of sagittal plane motion.
Only ankle and subtalar joint motions were analyzed in this study.
Because we did not place markers on the thigh or pelvis, we are unable
to determine hip movement during the sidestep cut. Six of the subjects
exhibited a sagittal plane pattern with little motion in the frontal
plane. We believe that these subjects may have externally rotated
at the hip in order to propel themselves 45º in a medial direction.
However, we are unable to prove this because that data that would
do so were not collected.
Subtalar/ankle joint complex kinematics have been reported in several
previous studies (Stacoff et al., 1996;
Neptune et al., 1999;
Simpson et al., 1999).
The 17º frontal plane range of motion of subjects the sagittal plane
group in our study is similar to that of the barefoot subjects of
Stacoff et al. (1996).
In that study, however, the maximum inversion angle was as much as
30º if shoes were worn (Stacoff et al., 1996).
Unfortunately, because sagittal plane data were not reported in that
study, comparisons of plantar flexion and dorsiflexion cannot be made
with our study. The subjects of Neptune, Wright, and van den Bogert
(1999) appeared
to exhibit a sagittal plane movement pattern. In that study, the plantarflexion/dorsiflexion
range of motion was approximately 35º , but minimal inversion/eversion
displacement was detected. It is not stated in that article what type
of footwear, if any, was worn by the subjects. Neither of these studies
have indicated that more than one movement pattern existed amongst
their subjects.
In a study by Simpson and colleagues (1999),
subjects contacted the ground in a neutral sagittal plane angle and
in 15º of inversion. They reached a maximum 35º of dorsiflexion and
inversion. A maximum of 5º of plantar flexion was achieved just after
heel strike and at toe off, resulting in a 40º sagittal plane range
of motion. The range of motion of the subjects in our sagittal plane
group was 26º . Our subjects, regardless of whether they used a sagittal
plane or frontal plane pattern, displayed much less range of motion
than these subjects (Simpson et al., 1999).
The peak inversion velocity of the subjects in our study is similar
to that reported by Simpson et al. (Simpson et al., 1999).
There may have been several reasons as to why the icing therapy had
minimal or no effect on the ankle joint movement in our study. The
ten-minute icing period of the current study may not have been enough
time to cool the joint area, resulting in minimal muscle cooling and
slowing of the nerve impulses. Therefore, ankle motion would not be
affected. We feel that the ten-minute period of the icing treatment
was an appropriate intervention because during halftime of athletic
events, ten minutes is considered a standard treatment time. Although
the use of ice bags may not have provided enough cooling to provoke
neuromuscular decrements, we selected this technique because it is
a commonly used method used to treat ankle injuries during halftime
of sporting events. An ice bath or boot may have been more effective
in cooling the ankle joint. A greater amount of tissue cooling may
be related to increased ankle instability (Denys, 1991).
Our research suggests that the standard ten-minute icing treatment
method used during halftime is not related to ankle instability because
no negative effects on ankle or subtalar joint movement patterns were
noted. Our findings are consistent with those of other researchers
who found that neither nerve conduction velocity nor joint position
sense were affected by a fifteen minute ice therapy session (Halar
et al., 1980; Hopper
et al., 1997).
We did not measure the cutaneous or subcutaneous temperature of the
shank and foot. We are therefore unable to quantify the precise amount
of tissue cooling and were unable to find the critical temperature
where intramuscular cooling began. We are only able to state that
the effects of the cryotherapy are similar to the effects that would
occur during a halftime, but cannot correlate the amount of change
of joint motion to the amount of tissue cooling.
The subjects did not wear shoes during the testing because we did
not want the various amounts of rearfoot control provided by different
types of athletic footwear to influence the subject's gait. Because
of budgetary constraints, we were not able to provide a single type
of footwear for use by all participants. In order to maintain consistency
of footwear, we required each subject to perform the sidestep cut
while barefoot. The subtalar/ankle joint kinematics may have been
altered because of this barefoot condition.
In the future, more extensive research should be done to investigate
the effects of cryotherapy on lower extremity movement during sidestep
cutting. Future studies should quantify the amount of tissue cooling,
as well as any change in cutaneous sensation and joint proprioception.
Further research should also be conducted to determine if longer cooling
periods have a greater effect on ankle instability, muscle contractions
and nerve conduction velocity. Because this study did not include
EMG, future research should be conducted to explore muscle activity
during a sidestep cutting maneuver during the pre and post stages
of ice therapy. This will help researchers understand specific muscle
twitch and contraction and relaxation phase changes.
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| CONCLUSIONS |
Due
to the current research findings, it is concluded that athletic trainers
and team doctors should continue the use of cryotherapy as a method
of treatment for ankle injuries during half time.
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| KEY
POINTS |
- Cryotherapy
does not affect ankle/subtalar joint movement.
- Subjects
utilize two different landing patterns: sagittal plane or frontal
plane dominant.
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| AUTHORS
BIOGRAPHY |
Beth L. ATNIP
Employment: Underground Fitness Center, University of Kentucky,
Lexington, KY 40506 USA
Degree: MS
Research interests: Biomechanics of sports injury and
rehabilitation
E-mail: birtha2@hotmail.com
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Jean L. McCRORY
Employment: Assistant Professor in the Department of
Sports Medicine and Nutrition in the School of Health and Rehabilitation
Sciences at the University of Pittsburgh. Associate Director
of the Neuromuscular Performance Laboratory at the UPMC Center
for Sports Medicine in Pittsburgh.
Degree: PhD
Research interests: Gait biomechanics, biomechanics of
sports injury and rehabilitation
E-mail: mccroryjl@msx.upmc.edu
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