Effect of walking and resting after three cryotherapy modalities on the recovery of sensory and motor nerve conduction velocity in healthy subjects

Abstract

Different cryotherapy modalities have distinct effects on sensory and motor nerve conduction parameters. However, it is unclear how these parameters change during the post-cooling period and how the exercise carried out in this period would influence the recovery of nerve conduction velocity (NCV).
To compare the effects of three cryotherapy modalities on post-cooling NCV and to analyze the effect of walking on the recovery of sensory and motor NCV.
Thirty six healthy young subjects were randomly allocated into three groups: ice massage (n=12), ice pack (n=12) and cold water immersion (n=12). The modalities were applied to the right leg. The subjects of each modality group were again randomized to perform a post-cooling activity: a) 30 min rest, b) walking 15 min followed by 15 min rest. The NCV of sural (sensory) and posterior tibial (motor) nerves was evaluated. Initial (pre-cooling) and final (30 min post-cooling) NCV were compared using a paired t-test. The effects of the modalities and the post-cooling activities on NCV were evaluated by an analysis of covariance. The significance level was α=0.05.
There was a significant difference between immersion and ice massage on final sensory NCV (p=0.009). Ice pack and ice massage showed similar effects (p>0.05). Walking accelerated the recovery of sensory and motor NCV, regardless of the modality previously applied (p<0.0001).
Cold water immersion was the most effective modality for maintaining reduced sensory nerve conduction after cooling. Walking after cooling, with any of the three modalities, enhances the recovery of sensory and motor NCV.

Full text

Or i g i n a l ar t i c l e
ISSN 1413-3555
Rev Bras Fisioter, São Carlos, v. 15, n. 3, p. 233-40, May/June 2011
©Revista Brasileira de Fisioterapia
Effect of walking and resting after three
cryotherapy modalities on the recovery of
sensory and motor nerve conduction velocity
in healthy subjects
Efeito da marcha e do repouso após aplicação de três protocolos de crioterapia na
recuperação da velocidade de condução sensorial e motora em sujeitos saudáveis
Esperanza Herrera1, Maria Cristina Sandoval1, Diana M. Camargo1, Tania F. Salvini2
Abstract
Background: Different cryotherapy modalities have distinct effects on sensory and motor nerve conduction parameters. However, it is unclear how
these parameters change during the post-cooling period and how the exercise carried out in this period would influence the recovery of nerve
conduction velocity (NCV). Objectives: To compare the effects of three cryotherapy modalities on post-cooling NCV and to analyze the effect of
walking on the recovery of sensory and motor NCV. Methods: Thirty six healthy young subjects were randomly allocated into three groups: ice
massage (n=12), ice pack (n=12) and cold water immersion (n=12). The modalities were applied to the right leg. The subjects of each modality
group were again randomized to perform a post-cooling activity: a) 30min rest, b) walking 15 min followed by 15 min rest. The NCV of sural
(sensory) and posterior tibial (motor) nerves was evaluated. Initial (pre-cooling) and final (30 min post-cooling) NCV were compared using a
paired t-test. The effects of the modalities and the post-cooling activities on NCV were evaluated by an analysis of covariance. The significance
level was α=0.05. Results: There was a significant difference between immersion and ice massage on final sensory NCV (p=0.009). Ice pack
and ice massage showed similar effects (p>0.05). Walking accelerated the recovery of sensory and motor NCV, regardless of the modality
previously applied (p<0.0001). Conclusions: Cold water immersion was the most effective modality for maintaining reduced sensory nerve
conduction after cooling. Walking after cooling, with any of the three modalities, enhances the recovery of sensory and motor NCV.
Keywords: cryotherapy; cold therapy; nerve conduction; cooling agents; sural nerve; tibial nerve.
Resumo
Contextualização: Diferentes protocolos de crioterapia têm ação distinta nos parâmetros de condução neural sensorial e motora. No
entanto, não se sabe como é o comportamento desses parâmetros no período pós-resfriamento e como o exercício físico realizado
nesse período atuaria na recuperação da velocidade de condução nervosa (VCN). Objetivos: Comparar o efeito de três protocolos
de crioterapia na VCN pós-resfriamento e analisar o efeito da marcha pós-resfriamento na recuperação da VCN sensorial e motora.
Métodos: Trinta e seis sujeitos jovens e saudáveis foram alocados aleatoriamente em três grupos: criomassagem (n=12), pacote de
gelo (n=12); imersão em água gelada (n=12). As modalidades foram aplicadas na perna direita. Os sujeitos de cada grupo foram
novamente aleatorizados para realizar uma atividade pós-resfriamento: a) 30 min de repouso; b) 15 min de marcha seguidos de 15 min
de repouso. Avaliou-se a VCN nos nervos sural (sensorial) e tibial posterior (motor). Comparações entre VCN inicial e final (30 min pós-
resfriamento) foram realizadas com teste t de Student pareado. Os efeitos das modalidades e das atividades pós-resfriamento na VCN
foram avaliados mediante análise de covariância. O nível de significância foi α=0,05. Resultados: Houve efeito diferente entre imersão
e criomassagem na VCN sensorial final (p=0,009). Pacote de gelo e criomassagem apresentaram efeitos similares (p>0,05). A marcha
acelerou a recuperação da VCN sensorial e motora, independente da modalidade previamente aplicada (p<0,0001). Conclusões:
Imersão em água gelada foi o procedimento mais eficaz para manter diminuída a condução nervosa sensorial após o resfriamento. A
marcha pós-crioterapia, com qualquer um dos três protocolos, acelera a recuperação da VCN sensorial e motora.
Palavras-chave: crioterapia; terapia por frio; condução nervosa; agentes de resfriamento; nervo sural; nervo tibial.
Received: 13/05/2010 – Revised: 17/11/2010 – Accepted: 14/02/2011
1 School of Physical Therapy, Health Faculty, Universidad Industrial de Santander (UIS), Bucaramanga, Santander, Colômbia
2 Laboratory of Muscle Plasticity, Department of Physical Therapy, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil
Correspondence to: Esperanza Herrera V, Ciudad Universitaria, Carrera 27 Calle 9, Escuela de Fisioterapia, Universidad Industrial de Santander, Bucaramanga, Santander, Colombia,
e-mail: eshevi@uis.edu.co
233
Rev Bras Fisioter. 2011;15(3):233-40.
233

Esperanza Herrera, Maria Cristina Sandoval, Diana M. Camargo, Tania F. Salvini
Introduction
Cryotherapy is a modality often used in clinical and sports
environments for treating musculoskeletal injuries both in the
acute phase and during rehabilitation. In the acute phase of the
injury, the cryotherapy is used mainly to reduce metabolism,
cellular hypoxia, pain and edema1-6. During the rehabilitation
phase, cryotherapy accelerates the process of tissue repair and
reduces pain, facilitating the performance of therapeutic exer-
cises and shortening the subject’s functional recovery1,3,4,6,7.
A reduction in tissue temperature is the primary eect of
cryotherapy, which leads to other physiological changes such as
a reduction in metabolic activity and nerve conduction velocity
(NCV)3,8. Several studies have analyzed the ecacy of cryother-
apy modalities for reducing cutaneous8-14, intramuscular7,9,14-16
and articular17 temperature. Previous studies have identied
that a crushed ice pack, ice massage and cold water immer-
sion are the most eective modalities for inducing greater and
faster cooling9-12. Other studies7,12,15 have compared the ecacy
of dierent modalities of cryotherapy in the maintenance of
tissue cooling after the end of cryotherapy, i.e., during the re-
warming period. Rewarming is understood as the recovery of
a tissue temperature level similar to that of pre-cooling7. After
cryotherapy the temperature of the skin recovers quickly12,
while intramuscular temperature remains reduced for some
minutes15. In two of the above-mentioned studies12,15, tissue
rewarming was analyzed while the subjects were at rest.
More recently, the eects of exercise after cryotherapy on
tissue rewarming have been analyzed. Myrer, Measom and
Fellingham7 identied that moderate walking, when compared
to rest, accelerates the rewarming of triceps surae muscle that
had been previously cooled with a crushed ice pack.
A possible explanation for this result is that exercise in-
creases metabolism, blood ow and heat production7. As a
consequence, post-cryotherapy exercise could reduce the du-
ration of other physiological eects of cooling such as a reduc-
tion in NCV.
ere is a direct and linear relationship between tissue
temperature and NCV18-24. As a consequence, cooling causes a
signicant reduction in sensory and motor NCV23-25. It is also
known that the hypoalgesic eect of cryotherapy, evidenced
by the increase in the threshold and tolerance of pain, is as-
sociated with a reduction in cooling- induced sensory NCV24.
In spite of the importance of NCV for hypoalgesic eects, few
studies23,25 have compared the ecacy of distinct modalities of
cryotherapy for reducing neural conduction. A recent study by
our group25, which evaluated the immediate eects of ice pack,
ice massage and cold water immersion on the NCV of sural
and posterior tibial nerves, showed that the three modalities of
cooling signicantly reduced the NCV of both nerves. However,
the sensory nervous bers were most aected by cooling, and
cold water immersion was the most eective modality for re-
ducing NCV (mainly motor NCV), probably because it involved
a greater area.
e literature on the late eects (post-cooling) of distinct
modalities of cryotherapy on sensory and motor NCV is scarce.
Consequently, it is unknown if the distinct modalities of cryo-
therapy are associated with dierences in the recovery of basal
levels (pre-cooling) of sensory and motor NCV. Furthermore,
no study has analyzed the eect of exercise performed imme-
diately after cooling on the recovery of NCV.
In light of the above-mentioned considerations, this study
was developed to answer the following questions: a) Are dis-
tinct modalities of cryotherapy associated with dierences in
the recovery of basal levels (pre-cooling) of sensory and motor
NCV? b) Does post-cooling exercise (walking) accelerate the
recovery of NCV?
is information would be important for recommending
dierent cryotherapy modalities to obtain therapeutic eects
associated with reduced NCV, such as hypoalgesia. is type of
study would have important clinical applications regarding ther-
apeutic exercise performed after cryotherapy (cryokinetics)7 or
in situations where the athlete returns to physical activity im-
mediately after being treated with cryotherapy.
e objectives of the present study were to compare the ef-
fects of three modalities of cryotherapy (ice massage, ice pack
and cold water immersion) on NCV recorded 30 min post-
cooling and to analyze the eect of post-cooling physical ex-
ercise (walking) on sensory and motor NCV. Considering that
cold water immersion is more ecient than other modalities
for reducing NCV25, as well as for keeping muscle cool during
rewarming15, the hypothesis of this study was that cold water
immersion would also be more eective for maintaining the
changes in NCV during the post-cooling period than either ice
massage or an ice pack. Moreover, considering that it has al-
ready been identied that post-cooling physical exercise accel-
erates muscular rewarming7, another hypothesis of the present
study was that post-cooling walking would also accelerate the
recovery of motor and sensory NCV.
Methods
An experimental study was conducted with 3 randomly
assigned intervention groups (ice massage, ice pack and cold
water immersion). For the post-cooling phase, the subjects
from each intervention group were randomized again for
one of the two post-cooling activity groups: a) 30 min of rest;
b) 15 min of walking followed by 15 min of rest (Figure 1).
is post-cooling protocol is similar to the one used by Myrer,
234
Rev Bras Fisioter. 2011;15(3):233-40.

Effect of exercise after cryotherapy on the nerve conduction recovery
Measom and Fellingham7 to analyze the eects of exercise
on muscular rewarming after cryotherapy. e independent
variables analyzed were: modality of cooling, post-cooling
activity and assessment time (pre-cooling and 30 min post-
cooling). e dependent variables were motor and sensory
NCV (m/s).
Subjects
is research project was approved by the Ethics Com-
mittee for Human Research of the Universidad Industrial de
Santander, Bucaramanga, Santander, Colombia under proto-
col no 18/2006. e subjects signed an informed consent form
after having the experimental procedures, risks and benets of
the research explained to them. All the participants lled out
a questionnaire on health aiming to determine the presence
of some of the following exclusion criteria: BMI<18.5 or >24.9,
history of alcoholism or smoking, cardiovascular or peripheral
vascular disease, diabetes, neurological or musculoskeletal dis-
ease, recent trauma or loss of sensitivity, adverse reactions to
cold, Raynaud’s Phenomenon and pregnancy25.
e calculation of the sample size for each intervention
group was determined by the sampsi command in Stata 9.0 ac-
cording to the following criteria: α=0.05; (1-β)= 0.9; ratio 1:1. e
calculation method was repeated measures analysis of covari-
ance (ANCOVA), with one initial and other nal measures and a
correlation between the measures of r=0.2. is method dened
a sample of 10-12 participants for each intervention group.
irty six healthy subjects (18 women and 18 men) were
enrolled in this study. e mean±SD age was 20.5±1.9 years,
mass 60.2±8.4 kg, height 1.63±0.1 m and BMI 22.4±1.6 kg/m2.
Instruments
e nerve conduction studies were carried out with Nico-
let Compass MeridianTM (Nicolet Biomedical Company, USA)
equipment.
e cooling modalities were chosen because they are con-
sidered the most eective for reducing tissue temperature9-14,16,25.
For ice massage, an 8×10×5 cm 279 g block of ice was used. e
ice pack was an 18×8 cm vacuum-sealed plastic sac containing
279 g of ice. Immersion was carried out in a 20×35×30 cm acrylic
Figure 1. The stages of experimental study, intervention groups and measurement times of motor and sensory nerve conduction velocity (NCV).
Each experimental session lasted approximately 60 minutes and consisted of three stages: acclimatization, cooling and post-cooling. The NCV was
measured at the three times indicated in the figure. The subjects were randomly assigned to one group of cooling modality: ice massage, ice pack or
cold water immersion. At the post-cooling stage, the subjects of each modality group were again randomized to do one of two post-cooling activities:
rest 30 min or walk 15 min followed of rest 15 min.
Acclimatization
15 min
Measurement of
pre-cooling
NCV
Measurement of
immediately
post-cooling NCV
Measurement of
30 min
post-cooling NCV
Rest 30 min
n=6
Walk 15 min and
rest 15 min
n=6
Cooling
15 min
Post-cooling
30 min
Ice Massage n=12
Ice Pack n=12
Cold Water immersion n=12
235
Rev Bras Fisioter. 2011;15(3):233-40.

Esperanza Herrera, Maria Cristina Sandoval, Diana M. Camargo, Tania F. Salvini
tank containing water and ice with a temperature of approxi-
mately 10°C. e tank’s temperature was measured throughout
the intervention and presented initial and nal means of 8.9±1.0
and 7.8±1.2°C, respectively. ere was no change or addition of
ice during any of the cryotherapy modalities.
Procedures
To minimize any circadian eects on body temperature, all
experiments were performed between 2:00 pm and 6:00 pm. e
subjects were allocated in the cooling and post-cooling activity
groups by random computer sequencing26. Considering that
the post-cooling measurements had to be taken immediately
after the administration of the modalities, the same room was
used for all interventions and assessment procedures. us, the
evaluator knew which intervention had been performed with
each subject. Room temperature was maintained at 24±0.08°C
without variation during the tests (p=0.29). e subjects were
instructed to wear comfortable clothes during the experiment.
e experimental protocol was developed in three phases: ac-
climation (15 min), cooling (15 min) and post-cooling (30 min)
as shown in Figure 1.
Acclimation phase
During this phase, which lasted 15 min, the subjects rested
in a prone position on a standard exam table. Meanwhile, the
exact area to be cooled was determined and the electrodes for
studying nerve conduction were attached. At the end of this
phase, the NCV pre-cooling data were obtained (Figure 1).
Cooling phase
The cooling modalities were applied for 15 min on
the right calf of each participant by a physical therapist
trained for this activity. This specific length of application
was chosen since it is commonly used in clinical practice
and avoids adverse cryotherapy effects27. The length of
time allotted for participant adaptation to the cold was
not considered before the experimental protocol. All par-
ticipants completed their cooling protocol with no adverse
reactions to the cold.
e procedures for determining the area for cooling treat-
ment are detailed in a previous study 25. In brief, for the ice
massage and ice pack interventions, the subjects remained
lying in a prone position and these modalities were applied
to a rectangular area (18×8 cm) on the right calf; compres-
sion was not used during the administration of the ice pack.
e ice massage was performed with continuous longitu-
dinal displacement. For cold water immersion, the partici-
pants remained seated while immersing their leg in a tank
to the upper edge of the rectangle that has been drawn for
the previous modalities (Figure 2). At the end of the inter-
vention, the leg was quickly dried without friction, and the
participant returned to the prone position for post-cooling
NCV measurements (Figure 1). ese data have already been
published recently25 and were not considered in the analysis
of the present study.
Post-cooling phase
In this phase, the subjects performed one of the randomly
determined activities. Half of the subjects from each modality
group (n=6) remained resting and lying prone on an exam table
for 30 min. e other half (n=6) walked for 15 min and then
rested for 15 min in the prone position. NCV was then reas-
sessed at 30 min post-cooling (Figure 1). e walking exercise
was carried out in a 9.45 m2 area at a frequency of 90 steps/
min, which was controlled by a metronome, i.e., the subjects
stepped at each “click” of the device.
Figure 2. Cryotherapy modalities.
A) Ice massage, B) Ice pack, C) Cold water immersion. The ice massage and ice pack were applied to the same rectangular area (18x8cm) of the calf. Ice massage was performed by
continuous longitudinal displacements. The ice pack was placed directly on the skin and without compression. For the cold water immersion, the participants immersed their right
leg in a cold water tank as far as the top border of the rectangle used to delimit the cooling area of the other two modalities.
ABC
236
Rev Bras Fisioter. 2011;15(3):233-40.

Effect of exercise after cryotherapy on the nerve conduction recovery
Nerve conduction studies
NCV was registered in the posterior tibial nerve (motor)
and in the sural nerve (sensory) at the previously-mentioned
times (Figure 1). ese nerves were selected because they are
located supercially within the treatment area and their re-
cording techniques have been well described25,28. Furthermore,
the posterior tibial nerve has a high quantity of motor bers,
and the sural nerve is a pure sensory nerve18,28 allowing assess-
ment of the cooling and post-cooling activity eects in both
motor and sensory nerves.
All nerve conduction studies were performed by same
experienced examiner. e good reliability of these recording
techniques repeatedly administered by the same examiner has
been previously established25,29. Surface electrodes were used
to stimulate and record nerve responses. In order to reduce
technical variations between repeated measurements, the
stimulation and recording sites were outlined with a waterproof
marker during the pre-cooling measurement and the recording
electrodes were not removed during the intervention, except
for the participants who received cold water immersion. For
this procedure, the recording electrodes were removed after
the pre-cooling measurement and replaced at the sites previ-
ously marked for post-cooling measurements. To calculate the
NCV, the peak latency of the negative wave25 was determined.
e sural nerve recordings were obtained with a bandwidth
of 20 Hz to 3 kHz, a gain of 20V/division, and a sweep speed
of 1 ms/division. A surface recording bar electrode was placed
immediately behind the lateral malleolus. e stimulating elec-
trode was placed about 14 cm proximal to the active recording
electrode, just lateral to the posterior midline of the calf25. e
stimuli were 100 μs rectangular pulses whose amplitude whose
amplitude was adjusted slightly higher than necessary to en-
sure a maximum response. e nerve signals were obtained by
averaging 20 responses.
e tibial motor nerve recordings were obtained with a
bandwidth of 2 Hz to 10 kHz, a gain of 2mV/division, and a
sweep speed of 2 ms/division. e active disc recording elec-
trode was placed over the abductor hallucis muscle, and the
reference disc recording electrode was placed at the base of the
hallucis. e ground electrode was positioned on the calf mus-
cle. e distal stimulation site was on the ankle immediately
behind the medial malleolus, and the proximal stimulation site
was at the popliteal fossa25.
Statistical analysis
Descriptive statistics were used to summarize population
characteristics and NCV data, which are presented as mean±SD30.
Baseline characteristics by intervention group were compared
by analysis of variance (ANOVA) or the χ2 test, depending of
the measurement scale of each variable26. NCV normality was
determined by the Shapiro-Wilk test26,30. e initially-recorded
NCV and the 30 min post-cooling NCV were then compared for
each post-cooling activity group with a paired t-test. e pur-
pose of this comparison was to determine whether there was a
complete recovery of NCV 30 min after cooling.
Finally, ANCOVA31 was performed to compare the eects of
the three modalities and the post-cooling activities on the 30
min post-cooling NCV, adjusting for the NCV measured imme-
diately after cooling. e group that received ice massage and
rested after cooling was the reference group for assessing the
modality eect. Stata 9.0 was used for statistical analysis with a
signicance level of α=0.05
Results
ere were no signicant dierences between participant
characteristics in either the three modality groups or the post-
cooling activity groups (p>0.05, Table 1).
Table 2 presents the results of the initial and nal NCV
(30 min post-cooling) comparisons. ere was a signicant
dierence between the initial and nal NCV of the posterior
tibial nerve in the groups that rested, regardless of the previ-
ously-used modality (p≤0.01). e cold water immersion group
that walked and rested also showed a signicant dierence
(p=0.019).
Signicant dierences were observed between the initial
and nal NCV (30 min post-cooling) of the sensory nerve in
all groups (p≤0.03), except for the group that walked and then
rested after having been treated with an ice pack (p=0.07). In
general, greater magnitudes of dierence were observed in the
sensory nerve and in the groups that remained at rest (Table 2).
e ANCOVA showed a signicant dierence between the
cold water immersion group and the group the received ice
massage on the sural nerve 30 min post-cooling NCV (p=0.009,
Table 3). is dierence was not observed in the motor signals
of the posterior tibial nerve (p=0.60, Table 3). ere were no
observed dierences in eect between ice pack and ice mas-
sage on 30 min post-cooling NCV (P>0.05, Table 3). Regarding
the eect of post-cooling activity on the recovery of motor and
sensory NCV, it was observed that, compared to 30 min of rest,
15 min of walking followed by 15 min of rest accelerated the
recovery of 30 min post-cooling NCV in both nerves (p<0.0001,
Table 3). is eect was more evident in the sensory nerve, and
the coecient for the sural nerve was higher (β=7.12) than
that determined for the posterior tibial motor nerve (β=3.99),
although the 95% condence intervals were not statistically
dierent (Table 3).
237
Rev Bras Fisioter. 2011;15(3):233-40.

Esperanza Herrera, Maria Cristina Sandoval, Diana M. Camargo, Tania F. Salvini
Discussion
e results of the present study showed that, compared to
only resting, the combination of post-cooling walking and rest-
ing accelerates the recovery of NCV in both sensory and motor
nerves, regardless of the cooling modality used (Table 3). More-
over, cold water immersion was the most eective modality for
maintaining decreased NCV 30 min after cooling, especially in
the sensory nerve, which was observed in a previous study25.
ese results conrm the hypotheses of this study.
In the literature reviewed, no previous studies were found
that evaluated the eect of the post-cooling activity on NCV.
However, considering the direct and linear relationship identi-
ed between tissue temperature and NCV18-24, we can compare
our results with the ndings of Myrer, Measom and Felling-
ham7, who investigated the eect of exercise (10 min of walking
on a treadmill at 5.63 km/h followed by 20 min of resting) on
the recovery of intramuscular temperature after applying an
ice pack for 20 min. e main nding of this study was that ex-
ercise accelerated muscle rewarming. It is known that exercise
increases muscle metabolism, blood ow and the production
of heat7,32,33. erefore, the subjects who exercised after cool-
ing activated the physiological processes that induce a faster
recovery of intramuscular temperature and, hence, NCV.
e immediate eect of cooling on NCV had been previ-
ously evaluated by our group, showing that sensory nerve bers
are more sensitive to cooling than motor bers25. e results of
this study also show that the magnitude of dierences between
initial and nal NCV (30 min post-cooling) in the sensory nerve
was highest when the subjects remained at rest (Table 2). How-
ever, there were no signicant dierences in these variables in
either nerve after the application of the three modalities (Table
Variable
Ice massage Ice Pack Cold water immersion
All
(n=12)
Rest
(n=6)
Walk and rest
(n=6)
PAll
(n=12)
Rest
(n=6)
Walk and rest
(n=6)
PAll
(n=12)
Rest
(n=6)
Walk and rest
n=6)
P
Age (y) 19.7±1.3 19.8±1.7 19.7±0.8 0.83 20.7±1 .3 20.7±1.8 20.8±1.0 0.84 20.9±2.6 21.5±2.3 20.3±2.9 0.46
Female
participants
n (%)
5 (41.7) 3 (50.0) 2 (33.3) 0.56 6 (50.0) 2 (33.3) 4 (66.7) 0.25 7 (58.3) 4 (66.7) 3 (50.0) 0.56
Height (m) 1.61±0.1 1.64±0.1 1.59±0.1 0.19 1.64±0.1 1.63±0.1 1.66±0.1 0.59 1.65±0.1 1.66 ±0.1 1.65±0.1 0.85
Mass (Kg) 58±7.1 59.9±6.4 56.3±7.9 0.40 60.4±8.6 60.7±6.5 60.2±10.9 0.93 62.1±9.7 64.8±10.6 59.6±9.0 0.38
Body mass
index (Kg/m2)22.2±1.6 22.2±1.6 22.3±1.9 0.91 22.3±1.4 22.9±1.4 21.7±1.2 0.14 22.6±1.7 23.4±1.3 21.9±1.8 0.11
Table 1. Characteristics of participants by modality and post-cooling activity groups.
Data are presented as mean±SD, except for the number and percentage of female participants.
Modality
Group
Post-cooling
activity Group
NCV of Posterior Tibial nerve (motor) NCV of Sural nerve (sensorial)
Pre-cooling 30min
post-cooling
Difference PPre-cooling 30min
post-cooling
Difference P
Ice massage Rest 50.3±2.2 45.7±2.7 -4.7±2.2 0.003 53.7±2.8 45.7±6.0 -8.0±4.9 0.01
Walk and rest 49.0±4.3 47.2±3.2 -1.8±2.0 0.08 54.2±3.1 52.2±3.5 -2.0±1.7 0.03
Ice pack Rest 50.2±4.8 44.7±4.1 -5.5±1.4 0.0002 51.5±5.2 44.5±4.2 -7.0±2.4 0.0008
Walk and rest 49.0±2.5 49.2±1.5 0.2±2.9 0.89 53.3±3.3 51.5±2.4 -1.8±1.9 0.07
Cold water
immersion
Rest 49.7±3.8 40.0±4.2 -9.7±3.6 0.001 54.8±2.4 39.5±2.3 -15.3±1.8 0.0000
Walk and rest 48.3±3.6 43.8±3.4 -4.5±3.2 0.019 53.3±6.2 48.5±4.9 -4.8±.6 0.02
Table 2. Results of paired t test comparing pre-cooling NCV with 30 min post-cooling NCV, by post-cooling activity group.
Table 3. Comparison of the cooling modality and the post-cooling activity effects on the NCV (30min post-cooling), by analysis of covariance
(ANCOVA). The 30min post-cooling NCV was adjusted by NCV obtained immediately after cooling. The modality group of comparison was the ice
massage and the post-cooling activity group of comparison was the rest.
Variable
Posterior Tibial nerve (motor) Sural nerve (sensorial)
Coefficient
(β)
95% Confidence
Interval
Probability
(P)
Coefficient
(β)
95% Confidence
Interval
Probability
(P)
Ice pack 0.23 -1.72; 2.19 0.81 -1.59 -4.73; 1.55 0.31
Cold water immersion 0.70 -2.00; 3.41 0.60 -4.23 -7.43; -1.15 0.009
Post-cooling activity:
walk 15min + rest 15 min 3.99 2.37; 5.60 <0.0001 7.12 4.57; 9.67 <0.0001
238
Rev Bras Fisioter. 2011;15(3):233-40.

Effect of exercise after cryotherapy on the nerve conduction recovery
2), which shows that, especially when subjects only rested, 30
minutes was not a sucient period of time to fully recover the
initial values of sensory and motor NCV.
Several studies8,10-12 have compared the eectiveness of
these modalities by measuring skin temperature, assuming
that changes in skin temperature are closely related to subcu-
taneous and intramuscular temperature changes. However,
it has also been reported that this assumption is not entirely
correct since skin temperature does not adequately represent
changes in deeper tissues or cooling eciency; skin tempera-
ture decreases faster and at a greater magnitude than muscle
temperature34,35.
Our results support this assertion due to the dierent
cooling eect observed in the two nerves situated at dierent
depths. We consider that since the sensory nerve is located
more supercially, its changes may be more associated with
variations in skin temperature9,15, while the observed changes
in the NCV of motor nerve bers, which are located more
deeply, may be more associated with a reduction of intramus-
cular temperature.
Cold water immersion was signicantly more eective in
maintaining changes in sensory nerve NCV 30 min after cooling
than the other modalities (Table 3). Moreover, the two groups
treated with this modality showed dierences between initial
and nal NCV, which shows that there was an incomplete re-
covery of sensory and motor NCV, regardless of post-treatment
activity (Table 2). is result is consistent with the greater ef-
fectiveness of cold water immersion for reducing sensory and
motor NCV immediately after cooling, which had been previ-
ously veried by Herrera et al.25. e greater eectiveness of
immersion for reducing and maintaining reductions in NCV
for 30 min is probably due to the fact that this modality cools a
larger area in comparison with the other two modalities, since
almost the entire surface of the leg and foot are immersed.
e technique of cold water immersion presents another
dierence in relation to ice massage and ice packs in that it is
the only modality applied with the lower limb aligned in op-
position to the treatment. In the other modalities, the limb was
positioned at the same level as the heart. Further studies are
necessary to investigate the importance of the extremity’s posi-
tion on the eectiveness of cryotherapy modalities.
We believe that our results provide additional information
for both scientic purposes and clinical practice regarding
the selection and implementation of cryotherapy modalities.
For example, the results show that when it is desired to keep
decreasing the sensory and motor NCV by cryotherapy, the
subject should remain at rest after the intervention. Cold water
immersion, as used in this study, is the modality most recom-
mended for maintaining the therapeutic eects of sensory
nerve conduction changes, such as hypoalgesia. Our results also
support the use of cryokinetics, since the three modalities were
able to alter sensory conduction at levels recommended to pro-
duce hypoalgesia25, which would allow the better performance
of therapeutic exercise after cooling. However, such exercise
limits the duration of the exercise hypoalgesic eect and re-
quires either the repetition of cryotherapy or the use of another
modality after exercise to increase the hypoalgesic eect.
Finally, it is important to point out that a continued de-
crease in NCV (30 min post-cooling), mainly in resting condi-
tions and without adequate supervision, involves a possible
risk of nerve damage in areas where the nerve passes super-
cially. e literature has shown cases of neuropathy due to the
application of cryotherapy along the course of more supercial
peripheral nerves27,36.
When analyzing the present study’s results, some meth-
odological limitations deserve consideration: the ice massage
and ice pack cooling area was smaller than that of cold water
immersion; the study population was composed of young and
healthy subjects, and it is possible that cooling causes dierent
eects in elderly and medically compromised subjects; the fact
that the examiner was aware of the modality used in each group
could aect the internal validity of the study; and the absence
of another NCV evaluation performed immediately after walk-
ing (in the walking/resting group) did not allow verication of
whether the subsequent 15 min of rest masked larger eects of
walking on NCV recovery.
Conclusion
Walking after cooling accelerated the recovery of sensory
and motor nerve conduction. Cold water immersion, as ad-
ministered, was the most eective modality for maintaining
reduced sensory nerve conduction.
Acknowledgments
To the Coordenação de Aperfeiçoamento do Pessoal de
Nível Superior (Capes, Brasil) for doctorate funding and to
the Universidad Industrial de Santander for nancing this
research.
239
Rev Bras Fisioter. 2011;15(3):233-40.

Esperanza Herrera, Maria Cristina Sandoval, Diana M. Camargo, Tania F. Salvini
References
1. Bleakley C, McDonough S, MacAuley D. The use of ice in the treatment of acute soft-
tissue injury. a systematic review of randomized controlled trials. Am J Sports Med.
2004;32(1):251-61.
2. Oliveira NML, Rainero EP, Salvini TF. Three intermittent sessions of cryotherapy reduce the
secondary muscle injury in skeletal muscle of rat. J Sports Sci Med. 2006;5:228-34.
3. Nadler SF, Weingand K, Kruse RJ. The physiologic basis and clinical applications of cryotherapy
and thermotherapy for the pain practitioner. Pain Physician. 2004;7(3):395-9.
4. Olson JE, Stravino VD. A review of cryotherapy. Phys Ther. 1972;52(8):840-53.
5. Kowal MA. Review of physiological effects of cryotherapy. J Orthop Sports Phys Ther.
1983;5(2):66-73.
6. Hubbard TJ, Aronson SL, Denegar CR. Does cryotherapy hasten return to participation? A
systematic review. J Athl Train. 2004;39(1):88-94.
7. Myrer JW, Measom GJ, Fellingham GW. Exercise after cryotherapy greatly enhances intramuscular
rewarming. J Athl Train. 2000;35(4):412-6.
8. Chesterton LS, Foster NE, Ross L. Skin temperature response to cryotherapy. Arch Phys Med
Rehabil. 2002;83(4):543-9.
9. Merrick MA, Jutte LS, Smith ME. Cold modalities with different thermodynamic properties
produce different surface and intramuscular temperatures. J Athl Train. 2003;38(1):28-33.
10. Kanlayanaphotporn R, Janwantanakul P. Comparison of skin surface temperature
during the application of various cryotherapy modalities. Arch Phys Med Rehabil.
2005;86(7):1411-5.
11. Janwantanakul P. Different rate of cooling time and magnitude of cooling temperature during ice
bag treatment with and without damp towel wrap. Phys Ther Sport. 2004;5(3):156-61.
12. Kennet J, Hardaker N, Hobbs S, Selfe J. Cooling efficiency of 4 common cryotherapeutic agents.
J Athl Train. 2007;42(3):343-8.
13. Belitsky RB, Odam SJ, Hubley-Kozey C. Evaluation of the effectiveness of wet ice, dry ice, and
cryogenic packs in reducing skin temperature. Phys Ther. 1987;67(7):1080-4.
14. Dykstra JH, Hill HM, Miller MG, Cheatham CC, Michael TJ, Baker RJ. Comparisons of cubed
ice, crushed ice, and wetted ice on intramuscular and surface temperature changes. J Athl Train.
2009;44(2):136-41.
15. Myrer JW, Measom G, Fellingham GW. Temperature changes in the human leg during and after
two methods of cryotherapy. J Athl Train. 1998;33(1):25-9.
16. Zemke JE, Andersen JC, Guion WK, McMillan J, Joyner AB. Intramuscular temperature responses
in the human leg to two forms of cryotherapy: ice massage and ice bag. J Orthop Sports Phys
Ther. 1998;27(4):301-7.
17. Warren TA, McCarty EC, Richardson AL, Michener T, Spindler KP. Intra-articular knee temperature:
changes ice versus cryotherapy device. Am J Sports Med. 2004;32(2):441-5.
18. Greathouse DG, Currier DP, Joseph BS, Shippee RL, Matulionis DH. Electrophysiologic
responses of human sural nerve to temperature. Phys Ther. 1989;69(11):914-22.
19. Dioszeghy P, Stalberg E. Changes in motor and sensory nerve conduction parameters
with temperature in normal and diseased ner ve. Electroencephalogr Clin Neurophysiol.
1992;85(4):229-35.
20. Halar EM, DeLisa JA, Brozovich FV. Nerve conduction velocity: relationship of skin subcutaneous
and intramuscular temperatures. Arch Phys Med Rehabil. 1980;61(5):199-203.
21. Halar EM, DeLisa JA, Brozovich FV. Peroneal nerve conduction velocity: the importance of
temperature correction. Arch Phys Med Rehabil. 1981;62(9):439-43.
22. Halar EM, DeLisa JA, Soine TL. Nerve conduction studies in upper extremities: skin temperature
corrections. Arch Phys Med Rehabil. 1983;64(9):412-6.
23. McMeeken J, Lewis MM, Cocks S. Effects of cooling with simulated ice on skin temperature and
nerve conduction velocity. Aust J Physiother. 1984;30:111-4.
24. Algafly AA, George KP. The effect of cryotherapy on nerve conduction velocity, pain threshold and
pain tolerance. Br J Sports Med. 2007;41(6):365-9.
25. Herrera E, Sandoval MC, Camargo DM, Salvini TF. Motor and sensory nerve conduction
are affected differently by ice pack, ice massage and cold water immersion. Phys Ther.
2010;90(4):581-91.
26. Pagano M. Principles of biostatistics. Belmont, Ca: Duxbury Press; 1993.
27. Malone TR, Engelhardt DL, Kirkpatrick JS, Bassett FH. Nerve injury in athletes caused by
cryotherapy. J Athl Train. 1992;27(3):235-7.
28. Oh SJ. Clinical electromyography: nerve conduction studies. 3rd ed. Philadelphia: Lippincott
Williams & Wilkins; 2003.
29. Herrera E, Camargo DM, Delgado DC, Salvini TF. Reliability of superficial peroneal, sural and
medial plantar nerve conduction studies: analysis of statistical methods. J Clin Neurophysiol.
2009;26(5):372-9.
30. Siegel S, Castellan NJ. Nonparametric statistics for the behavioral sciences. 2nd ed. New York,
NY: McGraw-Hill Inc; 1988.
31. Vickers AJ, Altman DG. Statistics notes: Analyzing controlled trials with baseline and follow up
measurements. BMJ. 2001;323(7321):1123-4.
32. Bender AL, Kramer EE, Brucker JB, Demchak TJ, Cordova ML, Stone MB. Local ice-bag
application and triceps surae muscle temperature during treadmill walking. J Athl Train.
2005;40(4):271-5.
33. Birch K, MacLaren D, George K. Sport and exercise physiology (Instant Notes). 1st ed. New York:
Garland Science/BIOS Scientific Publishers; 2005.
34. Jutte LS, Merrick MA, Ingersoll CD, Edwards JE. The relationship between intramuscular
temperature, skin temperature, and adipose thickness during cryotherapy and rewarming. Arch
Phys Med Rehabil. 2001;82(6):845-50.
35. Otte JW, Merrick MA, Ingersoll CD, Cordova ML. Subcutaneous adipose tissue thickness alters
cooling time during cryotherapy. Arch Phys Med Rehabil. 2002;83(11):1501-5.
36. Drez D, Faust DC, Evans JP. Cryotherapy and nerve palsy. Am J Sports Med. 1981;9(4):256-7.
240
Rev Bras Fisioter. 2011;15(3):233-40.