Available via license: CC BY-NC-ND 4.0
Content may be subject to copyright.
719
Original Article
Eect of Capacitive and Resistive electric
transfer on changes in muscle exibility and
lumbopelvic alignment after fatiguing exercise
Yuki Yokota, RPT1), takuYa Sonoda, RPT1), Yuto taShiro R P T, MS1),
YuSuke Suzuki, RPT, MS1), Yu kajiwara, RPT, MS1, 2), hala zeidan, RPT, MS1),
YaSuaki nak aYama, RPT1), mir ei kawagoe, RPT1), kanako Shimou ra, RPT1),
maSataka tatSumi, RPT1), kengo nak ai, RPT1), Yuichi niShida, RPT1),
tSubaSa bito, RPT1), SoYoka YoShimi, RPT1), tomoki aoYama, MD, PhD1)*
1) Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine,
Kyoto University: 53 Kawaharamachi Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
2) Department of Physical Therapy, Faculty of Health Science, Kio University, Japan
Abstract. [Pur pose] This study aimed to clarify the effects of Capacitive and Resistive electric transfer (CRet) on
changes in muscle exibility and lumbopelvic alignment after fatiguing exercise. [Subjects and Methods] Twenty-
two healthy males were assigned into either the CRet (n=11) or control (n=11) group. Fatiguing exercise and CRet
intervention were applied at the quadriceps muscle of the participants’ dominant legs. The Ely test, pelvic tilt,
lumbar lordosis, and supercial temperature were measured before and after exercise and for 30 minutes after in-
tervention. Statistical analysis was performed using one-way analysis of variance, with Tukey’s post-hoc multiple
comparison test to clarify within-group changes and Student’s t-test to clarif y between-group differences. [Results]
The Ely test and pelvic tilt were signicantly different in both groups after exercise, but there was no difference in
the CRet group after intervention. Supercial temperature signicantly increased in the CRet group for 30 minutes
after intervention, in contrast to after the exercise and intervention in the control group. There was no signicant
between-g roup difference at any timepoint, except in super cial temperature. [Conclusion] CRet could effectively
improve muscle exibility and lumbopelvic align ment after fatiguing exercise.
Key words: Thermotherapy, Lumbopelvic alignment, Muscle fatigue
(This article was submitted Dec. 30, 2017, and was accepted Feb. 27, 2018)
INTRODUCTION
Inappropriate lumbopelvic alignment is widely accepted as a risk factor for injuries. In particular, excessive anterior pelvic
tilt and lumbar lordosis are reported to be associated with injuries such as low back pain (LBP) and anterior cruciate ligament
(ACL) injury. Heather et al. reported that patients with LBP exhibited an increased lumbar lordosis compared with those
without LBP1). Roncarati and McMullen2) found an association between increased lumbar lordosis and anterior pelvic tilt
and LBP. Regarding ACL injury, Hertel et al.3) and Loudon et al.4) indicated that increased anterior pelvic tilt was related to a
history of ACL injury. These injuries are common in athletes and may prevent athletes from participating in sports for a long
time5, 6). Therefore, it is important to maintain the appropriate lumbopelvic alignment to prevent injuries.
Factors to dene lumbopelvic alignment include a balance between the anterior and posterior pelvic muscles. If a person
stands with an exaggerated anterior pelvic tilt and lumbar lordosis, his hip exor and lumbar extensor muscles are short-
J. Phys. Ther. Sci. 3 0: 719–725, 2018
*Corresponding author. Tomoki Aoyama (E-mail: blue@hs.med.kyoto-u.ac.jp)
©2018 The Society of Physical Therapy Science. Published by IPEC Inc.
This is an open-access ar ticle distributed under the term s of the Creative Commons Att ribution Non-Commercial No Derivatives
(by-nc-nd) License. (CC-BY-NC-ND 4.0: https://creativecommons.org /licenses/ by-nc-nd /4.0/)
The Journal of Physical Therapy Science The Journal of Physical Therapy Science
J. Phys. Ther. Sci. Vol. 30, No. 5, 2018 720
ened or tightened, whereas the abdominal muscles are
weakened7). Tashiro et al.8) revealed that anterior pelvic
tilt was signicantly greater in Japanese Keirin cyclists
than in the controls and concluded that poor exibility of
the quadriceps muscle, which includes the rectus femoris
muscle acting as a hip exor, contributed to an increase in
anterior pelvic tilt. Thus, a decrease in hip exor muscle
exibility can lead to excessive anterior pelvic tilt and
lumbar lordosis.
Muscle fatigue is one of the factors associated with de-
crease in muscle exibility. Various studies have reported
that muscle fatigue induced by intense exercise causes
an increase in muscle hardness, resulting in a decrease in
muscle exibility9–13). Therefore, muscle fatigue of the
hip exor is considered to change lumbopelvic alignment
by decreasing muscle exibility. Since poor muscle ex-
ibility itself is also related to the occurrence of injuries14–17), it is important to enhance muscle recovery after fatigue, and
maintain appropriate muscle exibility and lumbopelvic alignment.
Various modalities are utilized to facilitate muscle recovery from fatigue, including stretching18, 19), massage20, 21), active
recovery18, 22), contrast water therapy23, 24) cryotherapy25, 26), and thermotherapy27, 28). However, the effectiveness of these
modalities is controversial. Recently, Capacitive and Resistive electric transfer (CRet), which is a type of diathermy, has been
developed as a form of deep thermotherapy and applied in sports medicine29). This device delivers radiofrequency energy,
which passes between an active and inactive electrode, and generates heat within the body30, 31). Previous studies indicated
that CRet was more effective in improving blood circulation than a hot pack, which is a conventional thermotherapy modality
used frequently in clinical practice32, 33). Improving blood circulation would play an important role in the enhancement of
muscle recovery after fatigue34, 35). Thus, CRet can be an effective modality to enhance muscle recovery after fatigue, leading
to maintain and improve the appropriate muscle exibility and lumbopelvic alignment. However, there was no study indicat-
ing the effects of CRet on fatigued muscle and the changes in muscle exibility and lumbopelvic alignment after fatiguing
exercise are unknown. Therefore, the purpose of the present study was to clarify the effects of CRet on changes in muscle
exibility and lumbopelvic alignment after fatiguing exercise.
SUBJECTS AND METHODS
Twenty-two healthy males participated in the study. All participants were not active in spots and were not currently on
a regimented strenuous excessive exercise. The quadriceps muscles of their dominant legs received fatiguing exercise and
intervention. Individuals with a history of orthopedic or nervous system disease in their lower limbs or low back or who
corresponds with contraindication of the CRet intervention were excluded. Written informed consent was obtained from each
participant in accordance with the guidelines approved by Kyoto University Graduate School of Medicine and the Declara-
tion of Human Rights, Helsinki, 1975. The study was approved by the ethical committee of Kyoto University Graduate
School of Medicine (R1284).
The experimental design and time course of the measurements were summarized in Fig 1. Participants were randomly
assigned into one of two groups the CRet group or control group. The CRet group (n=11) received 15 minutes of CRet
intervention after fatiguing exercise, while the control group (n=11) was instructed to rest for 15 minutes. Measurements
were performed pre- and post- exercise (Pre-Ex and Post-Ex, respectively) and immediately, 15 minutes, and 30 minutes after
intervention (Post-In, 15 min Post-In, and 30 min Post-In, respectively).
Quadriceps muscle fatigue was induced in the participants’ dominant leg by concentric and eccentric knee extension
exercise. Participants sat on the bed with their hip joint angle at approximately 100° and their feet off the oor. From
this position, the participants were instructed to extend their knee fully over 3 seconds (concentric phase), keep their knee
extended for 1 second (isometric phase), and slowly lower the leg over 3 seconds (eccentric phase). They performed 10 sets
of 10 repetitions with a 30-second interval between sets. The resistance was set at approximately 30% of the participants’
maximum voluntary isometric contraction (MVC) force measured using a μ Tas F-1 hand-held dynamometer (Anima Corp.,
Tokyo, Japan).
Indiba® activ Pro Recovery HCR902 (Indiba S.A., Barcelona, Spain) was used for the CRet intervention. This device
operates at a frequency of 448 kHz. A rigid circular metallic electrode with a 65-mm diameter was used as the active electrode
and a large exible rectangular metallic plate (measuring 200 × 260 mm) was used as the inactive electrode. A radiofrequency
(RF) energy was delivered using in two modes: capacitive (CAP) and resistive (RES) at the active electrode. The CAP
electrode has a polyamide coating that acts as a dielectric medium, insulating its metallic body from the skin surface, and
thus it generates heat externally near the skin. The RES electrode is uncoated and the RF energy travels directly through the
body into the inactive electrode, therefore, it generates heat in deeper regions of the body. There are several contraindications
Fig. 1. The Ely test, pelvic tilt, lumbar lordosis, and supercial
temperature were measured before (Pre-Ex) and after
(Post-Ex) the fatiguing exercise. Then, the interventions
for CRet and cont rol groups were performed for 15 min-
utes. Each measu rement was performed immediately
(Post-In), 15 minutes (15-min Post-In), and 30 minutes
(30-min Post-In) after the interventions.
721
to receiving CRet including pregnancy, deep vein thrombosis, hypoesthesia, damaged skin, or the presence of an implanted
pacemaker. The CRet group underwent a 15-minute intervention (5 minutes in CAP mode, and 10 minutes in RES mode).
The active electrode was continually moved in the circular motion on the skin of posterior thigh and the inactive electrode
was placed under the thigh. A manufacturer- supplied conductive cream was used as coupling medium between the active
electrode and skin surface during the intervention. The intensity was determined subjectively by a score of 6 or 7 on a
subjective analog scale, which is an 11-point scale for the participant self-reporting of thermal sensing (0, no thermal sens-
ing; 10, worst possible thermal sensing). The intensity and duration of CRet intervention were based on the manufacturer’s
recommending method, which were considered to be the most effective without feeling discomfort or pain31).
The Ely test was used to determine changes in quadriceps muscle exibility36). The participants laid prone on the bed with
their dominant leg passively bent. The knee exion angle, at which the hip rise was felt by the examiner, was measured using
a universal goniometer.
Pelvic tilt was measured using a palpation meter (PALM, Performance Attainment Associates, St Pail, MN, USA)37).
During the measurements, the participants stood with their feet aligned with their shoulders and were instructed to keep their
arms crossed over the chest and look at a xed point ahead to control for postural sway. The landmarks for measurement
were the ipsilateral anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS). Anterior pelvic tilt was
measured by placement of the PALM caliper tips in contact with the ipsilateral ASIS and PSIS. The degree of deviation from
the horizontal was read from an inclinometer. A positive degree was used to describe anterior pelvic tilt and a negative degree
was used to describe posterior tilt in the sagittal plane. The measurements were performed two times on the participants’
dominant leg and the average value was used for analysis.
Lumbar lordosis was measured using the Spinal Mouse (Index Ltd., Tokyo, Japan)38). The Spinal Mouse is a computer-
aided electric measuring device that measures intersegmental angles in a non-invasive manner. As with PALM measurement,
the participants stood with their feet aligned with their shoulders and their arms beside the body; they were instructed to look
at a xed point ahead to control postual sway. The Spinal Mouse was guided along the midline of the spine beginning at the
spinous process of C7 and nishing at the top of the anal crease (approximately the level of S3). The lumbar lordosis angle
was calculated from the sum of six segmental angles from Th12/L1 to L5/S1. The measurements were performed three times
and the average value was used for analysis.
Supercial temperature was measured using an infrared thermometer (IT2-80, KEYENCE Co., Ltd., Japan) to estimate
the thermal effects of the CRet intervention. The measurement site was the center of the quadriceps muscle of the partici-
pants’ dominant legs.
For each measure index, the amount of change (Δ) from the rst value was calculated. The one-way analysis of variance
was used to analyze the changes at each time point within the group. The Tukey post hoc multiple comparison (Tukey-HSD)
test was performed to clarify differences within each group. The student t-test was used to compere changes at each time
point between two groups. Statistical analyses were performed using SPSS version 20.0 (IBM Corp., Armonk, NY, USA),
with a statistical threshold of 0.05.
RESU LT S
The physical characteristics of the participants in each group are shown in Table 1. There was no signicant difference in
the participants’ physical characteristics between groups. The mean resistance used in the knee extension exercise performed
by the CRet and control groups were 9.6 ± 1.4 kg and 9.2 ± 1.6 kg, respectively.
A signicant decrease in Ely test angle was observed at Post-Ex in the CRet group (p<0.05), and from Post-Ex to 30-min
Post-In in the control group (Post-Ex, Post-In, 15-min Post-In, p<0.01; 30-min Post-In, p<0.05). The pelvic tilt signicantly
increased at Post-Ex in the CRet group (p<0.01), and at Post-Ex and Post-In in the control group (p<0.01). There was no
signicant difference in lumbar lordosis in each group. Supercial temperature signicantly increased at Post-In, 15-min
Post-In, and 30-min Post-In in the CRet group (p<0.01), and at Post-Ex and Post-In in the control group (p<0.05) (Table 2).
Supercial temperature showed a signicant difference between groups from Post-Ex to 30-min Post-In (Post-Ex, 30-min
Tab le 1. Physical characteristics of the participants
CRet group (n=11) Control group (n=11)
Age (years) 23.0 ± 1.3 23.2 ± 2.3
Height (cm) 171.7 ± 5.3 168.5 ± 6.5
Weight (kg) 61.7 ± 7.8 60.0 ± 8.1
Body mass index (kg/m2)20.9 ± 2.4 21.1 ± 1.8
MVC (N) 331.5 ± 69.7 307.8 ± 57.9
Values are represented as mean ± standard deviation.
CRet: Capacitive and Resistive electric transfer; MVC: maximum voluntary
isometric contraction.
J. Phys. Ther. Sci. Vol. 30, No. 5, 2018 722
Post-In, p<0.05; Post-In, 15-min Post-In, p<0.01). There was no signicant difference in Ely test angle, pelvic tilt, and lumbar
lordosis between groups (Table 2).
DISCUSSION
In the present study, we investigated the effect of CRet intervention on changes in muscle exibility and lumbopelvic
alignment after fatiguing exercise. The results showed a signicant decrease in the angle of the Ely test and thus quadriceps
exibility, as well as a signicant increase in the angle of anterior pelvic tilt immediately after exercise in both groups. In the
control group, signicant differences in Ely test results and pelvic tilt were observed until 30 minutes after and immediately
after the intervention, respectively; while; in the CRet group, signicant differences in the Ely test and pelvic tilt were no
longer observed after CRet intervention.
Intense exercise, particularly which contains eccentric contraction, is known to induce an increase in muscle hardness9–11).
Repetitive muscle contractions frequently increase the intramuscular water content level39, 40). This exercise-induced uid
accumulation increases the intramuscular pressure, resulting in an increase in muscle hardness. Therefore, Ely test angle
signicantly decreased immediately after the knee extension exercise in both groups. This result suggests that the quadriceps
muscle exibility decreased immediately after knee extension exercise in both groups since the Ely test is an indicator of
quadriceps muscle exibility.
The results of the present study suggested that quadriceps muscle exibility returned to baseline sooner in the CRet group
than in the control group. This difference seems to be due to the thermal effects of the CRet intervention. In the present
study, the change in supercial temperature was 5.1°C immediately after CRet intervention. Our previous study showed that
the change in supercial temperature was 2.4°C immediately after CRet intervention applied at the hamstring muscles33).
Although we measured supercial temperature using a different instrument, the intervention in the present study was carried
out at the same intensity and duration using the same instrument as in this previous study. Therefore, we assumed that the
thermal effects in the present study may be equal to or higher than in the previous study.
There are three possible factors contributing to the change in quadriceps muscle exibility. The rst factor is improvement
in blood circulation to the muscle. Many studies have revealed that thermotherapy improves blood circulation34, 35, 41, 42).
Tab le 2 . Changes in the measurement value
CRet group Control group
Ely test (°) Pre-Ex 0 0
Post-Ex −6.0 ± 3.0*−6.5 ± 2.8**
Post-I n −2.6 ± 5.8 −5.8 ± 2.7**
15-min Post-In −3.2 ± 5.7 −3.9 ± 2.0**
30-min Post-In −3.4 ± 6.0 −3.1 ± 2.6*
Pelvic tilt (°) Pre-Ex 0 0
Post-Ex 1.9 ± 1.2** 1.4 ± 0.9**
Post-I n 0.5 ± 0.8 1.1 ± 0.8**
15-min Post-In −0.9 ± 0.8 0.5 ± 0.7
30-min Post-In 0.0 ± 0.9 0.4 ± 0.7
Lumbar lordosis (°) Pre-Ex 0 0
Post-Ex −1.1 ± 2.2 −1.1 ± 4.8
Post-I n −1.7 ± 2.6 −0.8 ± 4.0
15-min Post-In −0.8 ± 2.5 0.2 ± 3.7
30-min Post-In −0.3 ± 2.3 −1.4 ± 3.4
Supercial temperature (°C) Pre-Ex 0 0
Post-Ex 0.3 ± 0.7†0.9 ± 0.6*†
Post-I n 5.1 ± 1.3**‡ 0.9 ± 0.7*‡
15-min Post-In 2.9 ± 1.0**‡ 0.6 ± 0.8‡
30-min Post-In 1.7 ± 1.3**‡ 0.6 ± 0.8†
Values are represented as mean ± standard deviation.
*Signicant difference from Pre-Ex value ( p<0.05, Tukey-HSD).
**Signicant difference from Pre-Ex value (p<0.01, Tukey-HSD)
†Signicant difference between groups (p<0.05, Student t-test)
‡Signicant difference between groups (p<0.01, Student t-test)
CRet: Capacitive and Resistive electric transfer.
723
Moreover, previous studies showed that CRet intervention was more effective on the improvement in blood circulation than
hot pack application32, 33). An increase in muscle hardness is caused by an increase in intramuscular pressure resulting from
uid accumulation9). We infer that muscle hardness may decrease since the accumulated uid would be removed by the
improvement in blood circulation from CRet intervention. Muscle hardness affects muscle exibility, thus, muscle exibility
of the quadriceps could be improved by CRet intervention. The second factor is the increase in soft tissue extensibility,
including that in connective tissue composed primarily of collagen bers43–45). As temperature increases, collagen extensibil-
ity increases, and connective tissue viscosity and the viscoelasticity of muscle bers are reduced46–48). Subsequently, the
extensibility of soft tissues increases, and muscle exibility improves. The third factor is muscle relaxation. Thermal stimula-
tion decreases the activity of α motor neurons by changing the activity of group II bers, γ motor neurons and Ib bers49).
These changes in neuronal activity cause muscle relaxation. In the present study, thermal stimulation by CRet intervention
may alter nerve activity and cause muscle relaxation, resulting in improvement in quadriceps exibility based on the Ely test.
The result of the present study showed that the pelvic tilt angle signicantly increased immediately after exercise in both
groups and returned to its original value sooner in the CRet group than in the control group. These changes are considered to
be associated with the change in quadriceps muscle exibility. The position of the pelvis is determined by a balance between
the anterior and posterior pelvic muscles. Kendall et al.50) described that tightness of the hip exors led to an anterior pelvic
tilt in the standing position. The quadriceps muscle group is composed of four muscle, vastus lateralis, vastus medialis,
vastus intermedius, and rectus femoris; the rectus femoris also acts as a hip exor. Thus, it is considered that the angle of
pelvic tilt increased immediately after knee extension exercise and decreased after CRet intervention, along with a change in
quadriceps muscle exibility.
There was no signicant difference in lumbar lordosis in both groups at any time point. It is widely believed that lumbar
lordosis is associated with pelvic tilt. Levine et al.51) found that altering pelvic tilt signicantly changed the angle of lumbar
lordosis in the standing position. According to Youdas et al.52), the correlation between pelvic tilt and lumbar lordosis in the
standing position is signicant, albeit weak. We assume that the change in pelvic tilt was insufcient to affect lumbar lordosis
because the exercise and intervention were performed on participants’ dominant legs only.
Poor muscle exibility is a risk factor of various injuries14–17), thus it is important to maintain and improve muscle ex-
ibility to prevent injuries. Furthermore, inappropriate lumbopelvic alignment could cause injuries such as low back pain1, 2)
and ACL injury3, 4). The results of the present study indicated that fatiguing exercise decreased muscle exibility, resulting
in a change in pelvic alignment. Those who perform fatiguing exercise on a daily basis, for example athletes, require a faster
recovery from fatigue and enhance injury prevention through the appropriate conditioning in order for them to optimally
practice and to compete. Moreover, it is important to recover muscles after strenuous exercise in a short time because, in
many sports, situations in which athletes are not given enough time to recover their muscle fatigue are abundant; for example,
the situation in which they have to participate in a lot of games in a day. Our study results suggest that CRet could play an
important role in athletes’ conditioning.
This study had several limitations. First, we did not include female and various aged participants, and the population was
restricted to young healthy males belonging to the same university. The effects of CRet in other populations is uncertain;
therefore, further research is required in this regard. Second, we assessed the quadriceps muscle only by the Ely test. The
detailed changes caused by exercise and CRet intervention remain unclear. Third, the measurement time was limited. We
investigate the effects of CRet on changes in muscle exibility and lumbopelvic alignment before and after exercise and for
30 minutes after intervention. The lasting effects of these are unknown. Thus, studies with long-term follow up are needed.
Despite these limitations, the results of the present study provide valuable information on the effects of CRet.
The effects of CRet on changes in muscle exibility and lumbopelvic alignment after fatiguing exercise was investigated.
The results showed that the changes in quadriceps muscle exibility and anterior pelvic tilt was signicant immediately
after knee extension exercise in both groups; however, that these indexes returned to the pre-exercise value sooner in the
CRet group than after intervention. These ndings suggest that the CRet intervention is effective on improvement of muscle
exibility and pelvic tilt after fatiguing exercise. CRet could be a useful means to recover muscle fatigue and maintain the
appropriate muscle exibility and lumbopelvic alignment.
Conict of interest
None.
REFERENCES
1) Christ ie HJ, Kum ar S, Warren SA: Postu ral abe rrat ions in low back pain . Arch Phys Me d Rehabil, 1995, 76: 218–224. [ Medline] [Cross Ref ]
2) Roncarat i A, McMullen W: Correlates of low back pain in a gener al population sample: a multidisciplinar y persp ective. J Man ipulative Physiol Ther, 1988, 11:
158 –164. [ Me dl in e]
3) Hertel J, Dor fman J H, Braha m RA: Lower ext remity malalig nments and ante rior cr uciate liga ment inju ry history. J Sport s Sci Med, 2004, 3: 220–225. [M ed li ne]
4) Loudon J K, Jen kins W, Loudon KL: The rela tionsh ip between static pos ture and ACL injury in fema le athle tes. J O rthop Spor ts Phys T her, 1996, 24: 91–97.
[Me dl ine] [Cros sRe f]
5) Schmidt CP, Zwingenbe rger S, Walther A, et al.: Prevalenc e of low back pain in adole scent athletes - an epidemiological invest igation. Int J Sport s Med, 2014,
J. Phys. Ther. Sci. Vol. 30, No. 5, 2018 724
35: 684–689. [ Med li ne] [Cro ssR ef ]
6) Prodrom os CC, Han Y, Rogowski J, et al.: A meta-analysi s of the incidence of anterior cr uciate ligament tea rs as a function of gender, spor t, and a knee injury-
reduct ion regimen. Ar thr oscopy, 2007, 23: 1320–1325.e6. [Medli ne] [C ros sRe f ]
7) Kisner C, C olby LA: Therapeut ic exercise: foundat ions and t echniques, 6t h ed. Phil adelphia: F.A. Davis, 2012.
8) Tashiro Y, Hasegawa S, Nish iguchi S, et al.: Body cha racte rist ics of profession al Japane se Keir in cyclist s: exibility, pelvic tilt, and muscle streng th. J Sports
Sci, 2016, 4: 341–345.
9) Yanagisawa O, Niit su M , Ku rihara T, et al.: Eva luation of human muscle hardness after dynam ic exe rcise with ultrasoun d re al-time t issue elastography: a
feasibil ity st udy. Clin Radiol, 2011, 66: 815–819. [Me dl in e] [Cr os sRef]
10) Yanagisawa O, Saku ma J, Kawaka mi Y, et al.: Effect of exercise-induced muscle damage on muscle ha rdnes s evaluate d by ultras ound real-time ti ssue elastog-
raphy. Sprin gerplu s, 2015, 4: 308. [Me dl in e] [Cr oss Ref ]
11) Murayama M, Nosaka K, Yoneda T, et al .: Cha nges in hard ness of the hu man elbow exor muscles after ec centr ic exercise. Eur J Appl Phy siol, 2000, 82:
361–367. [Med line] [Cro ss Ref ]
12) Niitsu M, M ichizaki A, En do A, et al.: Muscle hardness measu rement by using u ltrasound elastog raphy: a feasibilit y st udy. Acta Rad iol, 2011, 52: 9 9–105.
[Me dl ine] [Cros sRe f]
13) Akag i R, Tanaka J, Shikiba T, et al.: Muscle hardness of the tr iceps bra chii before an d after a resistance exer cise session: a shear wave ultrasound elast ography
study. Acta R adiol, 2015, 56: 1487–1493. [Medl ine] [C ros sRe f ]
14) Feldman DE, Sh rier I, Ros signol M, et al.: Risk factors for the developm ent of low back pain in a dolescen ce. Am J Epidemiol, 2001, 154: 30 –36. [ Med li ne]
[Cro ssR ef ]
15) Witvro uw E, Danneels L, Asselman P, et al.: Muscle exibility as a risk factor for developin g muscle injurie s in male professional socc er players. A prospec tive
study. Am J Sports Me d, 2003, 31: 41–46. [Me dl ine] [C ros sRe f ]
16) Bradley PS, Por tas M D: The r elationship between p reseason ran ge of motio n and mu scle strain i njur y in el ite soccer player s. J St rengt h Cond Res, 200 7, 21:
1155 –1159. [Medli ne]
17) Witvro uw E, Bellemans J, Lysens R, et al.: Intrinsic r isk fa ctors for th e development of patella r tendinitis i n an athletic po pulation. A two-year prospective
study. Am J Sports Me d, 2001, 29: 190–195. [Me dl ine] [C ros sRe f ]
18) Mika A, Mika P, Fern hall B, et al.: Comparison of recovery strategies on muscle perfor mance aft er f atigu ing exercise. Am J Phy s Med Rehabil, 20 07, 86:
474–4 81. [Med li ne] [Cro ssR ef ]
19) Ghasem i M, Bag heri H, Olyaei G, et al.: Effect s of cyclic st atic st retch on fatigu e recover y of triceps su rae in female ba sketball players. Biol Sport, 2013, 30:
97–102. [Med li ne] [C ros sRe f ]
20) Rinde r AN, Sutherla nd CJ: An invest igation of the ef fects of massa ge on qu adr iceps perfor mance afte r exerci se fatig ue. Complement T her Nurs Midw ifery,
1995, 1: 99–102. [Me dl in e] [Cr ossRef ]
21) Robert son A, Watt JM , Galloway SD: Effe cts of leg massage on recover y from h igh inte nsity cycl ing exerci se. Br J Sport s Med, 200 4, 38: 173–176. [Medli ne]
[Cro ssR ef ]
22) Vanderthommen M , Mak rof S, Demoulin C: Compari son of act ive and elec trost imulat ed recove ry st rategies aft er fatig uing exercise. J Sports Sci Med, 2010,
9: 164–169. [Med li ne]
23) Elias GP, Varley MC, Wyckelsma VL, et al.: Effects of water im mersion on posttraini ng recover y in Austra lian footba llers. I nt J Sports Physiol Perform, 2012,
7: 357–366. [Med li ne] [Cro ssR ef ]
24) Webb NP, Harris NK , Cronin J B, et al.: The relat ive efcac y of three recovery mod alitie s after professional rugby leag ue matche s. J Streng th Cond Res , 2013,
27: 2449–2455. [Me dl in e] [Cr os sRef ]
25) Leeder J, Gissane C, van Somer en K, et al.: Cold water immersion and re covery from strenu ous exercise: a meta-analysis. Br J Sports Med , 2012, 46: 233–240.
[Me dl ine] [Cros sRe f]
26) Eguchi Y, Jinde M, Murooka K, et al.: Stretchi ng vers us transitory icing: which is t he more effective treatment for att enuat ing mu scle fatigue af ter repeate d
manual labor? Eu r J Appl Physiol, 2014, 114: 2617–2623. [Med li ne] [Cro ssR ef ]
27) Pereira WM, Ferreira LA , Rossi LP, et al.: Inu ence of heat on f atigue and elect romyographic act ivity of t he biceps brachii muscle. J Body w Mov Ther, 2011,
15: 478–484. [Med li ne] [Cro ssR ef ]
28) Brazait is M, Skurvyda s A, Vadopalas K , et al.: The effect of heating and cooling on time cou rse of volunt ary an d electr ically induced muscle forc e variat ion.
Medicin a (Kau nas), 2011, 47: 39–45. [ Med li ne]
29) Herná ndez-Bu le M L, Paíno CL, Trillo M A, et a l.: Ele ctric st imulat ion at 4 48 kHz promotes prolifer ation of human mesenchymal stem cells. Cell Physiol
Biochem, 2014, 34: 1741–1755. [Me dl i ne] [C ros sRe f ]
30) Kato S, Saitoh Y, Miwa N: Repressive effects of a capacitive-r esistive elect ric transfer (CRet) hypert herm ic apparat us combined with provitamin C on intra cel-
lular li pid-dr oplets for mation i n adipocyte s. Int J Hyp ert herm ia, 2013, 29: 30–37. [Me dl in e] [Cr oss Ref ]
31) Kumar an B, Watson T: Ther mal bu ild-up, decay a nd ret ention r espon ses to local t herap eutic application of 448 kHz ca pacitive resist ive monop olar ra diofre -
quency: a prospec tive rand omised c rossover s tudy in healthy a dults. I nt J Hyperthermia , 2015, 31: 883–895. [ Med line] [Cro ss Ref ]
32) Tashiro Y, Hasegawa S, Yokota Y, et al.: Effect of capacit ive and resistive elect ric tr ansfer on haemoglobi n satu ration a nd tissue t emper atur e. Int J Hyperthe r-
mia, 2017, 33: 696–702. [Me dl in e] [Cr os sRef]
33) Yokota Y, Tashi ro Y, Suzuk i Y, et al.: Effect of capacit ive and re sistive electric tran sfer on ti ssue te mperat ure, muscle exibility a nd blood circulation. J Nov
Physiother, 2017, 7: 325–331. [Cros sRe f ]
34) Robinson SE , Buono MJ: Effect of cont inuous -wave ultra sound on blood ow in skele tal muscle. Phys Ther, 1995, 75: 145–149, discussion 149–150. [Me dl in e]
[Cro ssR ef ]
35) Baker RJ, Bell GW: The effect of therap eutic mod alitie s on blood ow in t he huma n calf. J O rthop S ports Phys Ther, 1991, 13: 23–27. [Med li ne] [Cro ssR ef ]
36) Piva SR, Goodnit e EA, Childs JD: Streng th aroun d the hip and exibility of soft tissues in individual s with and without patellofemoral pain synd rome. J Orthop
Sport s Phys Ther, 20 05, 35: 793–801. [Me dl in e] [Cr oss Ref ]
37) Herr ingto n L: Assessment of the deg ree of pelv ic tilt wit hin a nor mal asymptomatic popu lation. M an Ther, 2011, 16: 646–6 48. [M ed li ne] [C rossRef ]
725
38) Masak i M, Ikezoe T, Fukumoto Y, et al.: Association of sagitt al spinal alignme nt with thick ness and echo intensity of lumbar back muscles in mid dle-aged and
elderly women . Arch Ge rontol Ger iatr, 2015, 61: 197–201. [M ed li ne] [C rossR ef ]
39) Yamauchi J, Ha rgens A: Ef fects of dy nam ic and sta tic hand grip exercise s on hand an d wris t volume. Eur J Appl Physiol, 20 08, 103: 41–45. [Med li ne] [Cro ssR ef ]
40) Yanagisawa O, Kudo H, Takahashi N, et al.: Magnetic resonance imaging evaluation of cooling on blood ow and oedema in skeletal muscles after exercise.
Eur J Appl Physiol, 2004, 91: 737–740. [Med line] [Cross Ref ]
41) Morish ita K, K arasu no H, Yokoi Y, et al.: Effects of therapeutic u ltras ound on i ntra muscul ar blood ci rculation and ox ygen dyn amics. J Jpn Phys The r Assoc ,
2014, 17: 1–7. [Med li ne] [C ros sRe f ]
42) Wyper DJ, McNiven DR: The effec t of microwave therapy up on muscle bloo d ow in man. Br J Sport s Med, 1976, 10: 19–21. [Medl ine] [Cr oss Ref ]
43) Lehma nn JF, Warre n CG, Scham SM: Therapeutic he at and cold. Clin Or thop Relat Res, 1974, (99): 207–245. [Medline] [Cross Ref ]
44) Strick ler T, Malone T, Gar rett W E: The effects of passive warm ing on muscle injur y. Am J Sport s Med, 1990, 18: 141–145. [Me dl in e] [Cr oss Ref ]
45) Lentell G, Hetherington T, Eagan J, et al.: The use of the rmal agents to in uence t he effect iveness of a low-load prolonged str etch. J Or thop Spor ts Phys Ther,
1992, 16: 200–207. [M ed li ne] [Cro ssR ef ]
46) Warren CG, Lehma nn JF, Koblanski JN: Heat and stretch procedur es: an evaluation usin g rat tail tendon. Arch Phys Med Rehabil, 1976, 57: 122–126. [Me dl in e]
47) Mutung i G, Ranatunga KW: Temperatu re-dependent ch anges in the viscoelasticit y of inta ct r esting ma mmal ian (rat) fast- and slow-twitch muscle bres. J
Physiol, 1998, 508: 253–265. [ Med li ne] [Cro ssRef ]
48) Lehma nn JF, Masock A J, Warren CG, et al.: Effect of therapeutic temperat ures on te ndon extensibilit y. Arch Phys Med Rehabil, 1970, 51: 481–487. [M ed li ne]
49) Cameron MH: Physical agents in rehabil itation f rom research to pr actice, 4th ed. Ph iladelp hia: Sau nders, 2009.
50) Kendal l HO, Kendall FP, Wadsworth GE: Muscle s: testi ng and f unction. Balti more: Lippi ncott William s and Wilkins, 1993.
51) Levine D, Whitt le MW: The effect s of pelvic moveme nt on lumbar lordosis in t he stan ding position. J Or thop Spo rts Phys T her, 1996, 24: 130–135. [Me dl in e]
[Cro ssR ef ]
52) Youdas JW, Garret t TR, Egan KS, et al.: Lumbar lordosis and pelvic incl inat ion in adult s with chron ic low back pain. Phys T her, 2000, 80: 261–275. [Med li ne]