Do thermal agents affect range of movement and mechanical properties in soft tissues? A systematic review.
Topic: Hyperthermia

To examine the effect of thermal agents on the range of movement (ROM) and mechanical properties in soft tissue and to discuss their clinical relevance.

PICO
Population: Patients with soft tissue injuries or conditions affecting range of movement and mechanical properties
Intervention: Thermal agents (e.g., heat therapy, cold therapy)
Comparison: No thermal agent or alternative therapy
Outcomes: Changes in range of movement and mechanical properties in soft tissues

Included studies:
title: Effects of ultrasound and stretch on knee ligament extensibility.
abstract: Randomized, double-blind pre-test and post-test with repeated measures.
title: Effects of static stretch versus static stretch and ultrasound combined on triceps surae muscle extensibility in healthy women.
abstract: The purpose of the study was to demonstrate for the first time on human subjects that static stretch and ultrasound (SS and US) combined increases triceps surae muscle extensibility more than SS alone. The SS and US combined consisted of seven minutes of continuous US at 1.5 W/cm2 to the muscle with SS during the seventh minute. The SS alone consisted of a 51-lb (23.1 kg) load applied for one minute. We randomly assigned 10 healthy, female subjects to each of three groups (N = 30). Each group received each of the three types of treatment (SS and US, SS, and no treatment) in a different order. Standardized goniometric measurements of active dorsiflexion were taken before and after each treatment session. The SS and US treatment increased dorsiflexion an average of 1.2 degrees, or 20%, more than the SS treatment. The SS treatment increased dorsiflexion an average of 1.3 degrees, or 27%, more than no treatment. Both increases were statistically significant.
title: The use of thermal agents to influence the effectiveness of a low-load prolonged stretch.
abstract: This study was funded in part by a Minigrant award from California State University, Fresno. The use of thermal modalities to enhance stretching procedures is not well documented clinically. This study documented the effectiveness of applying superficial heat and cold in conjunction with a low-load prolonged stretch (LLPS) for increasing shoulder flexibility. Ninety-two healthy males were randomly assigned to one of five groups: 1) an LLPS alone, 2) heat applied in the initial phase of an LLPS, 3) cold applied in the final phase of stretch, 4) a combination of heat initially followed by cold, and 5) no intervention. Subjects received three, 40-minute treatments across a 5-day period. A follow-up measurement was taken 3 days later. Results demonstrated that an LLPS associated with the use of heat, ice, or a combination of both facilitated greater long-term improvements in flexibility compared with controls. However, only subjects receiving heat in the initial phase of an LLPS showed significant gains when compared with those who received stretching alone (p </= 0.05). We concluded that applying heat in conjunction with an LLPS to a nonpathologic shoulder is a clinically superior method of improving flexibility compared with an LLPS alone. J Orthop Sports Phys Ther 1992;16(5):200-207.
title: Effect of Fluori-Methane spray on passive hip flexion.
abstract: The purpose of the study was to evaluate the influence of Fluori-Methane spray as a method of affecting passive range of motion measured at the right hip joint. Subjects were 30 normal volunteers randomly divided into an experimental group and a control group. A special table was constructed to position and stabilize each subject for monitoring the right lower extremity's resistance to side-lying straight leg raising. Specific right hip flexion goniometric measurements were compared and analyzed before and after application of Fluori-Methane spray to the soft tissue overlying the posterior part of the right thigh. The results of the study showed that the experimental group, which received application of Fluori-Methane spray and static passive stretch, did significantly (p less than .02) increase the range of passive hip flexion over that of the control group, which received only static passive stretch.
title: Effect of heat modalities on hamstring length: a comparison of pneumatherm, moist heat pack, and a control.
abstract: Prospective, researcher-blinded, repeated-measures, randomized complete block design.
title: [Research on the preparation of vials with drinkable N-acetylglutamic acid diethylaminoethanol for use in infants].
title: Comparison in the effect of linear polarized near-infrared light irradiation and light exercise on shoulder joint flexibility.
abstract: This study aimed at comparing the effect of linear polarized near-infrared light irradiation (PL irradiation) and bicycle exercise with 50%HRreserve on the flexibility of the shoulder joint.
title: The Carry-Over Effects of Diathermy and Stretching in Developing Hamstring Flexibility.
abstract: OBJECTIVE: To compare the effects of low-load, short-duration stretching with or without high-intensity, pulsed short-wave diathermy on hamstring flexibility. DESIGN AND SETTING: We used a single-blind, repeated-measures design (pretest and posttest for all treatments) that included a placebo. The 3 independent variables were treatment mode, pretest and posttest measurements, and day. Treatment mode had 3 levels: diathermy and stretching, stretching alone, and control. The dependent variable was range of motion. Subjects were randomly assigned to the diathermy and stretching, stretching-only, or control group. Subjects were treated and tested each day (at approximately the same time) for 5 days, with a follow-up test administered 72 hours later. Hamstring flexibility was tested using a sit-and-reach box before and after each treatment. Diathermy and stretching subjects received a 15-minute diathermy treatment on the right hamstring at a setting of 7000 pulses per second, with an average pulse width of 95 μsec. Stretching-only subjects received a 15-minute sham diathermy treatment. Both diathermy and stretching and stretching-only subjects then performed three 30-second stretches (short duration) before being retested. Control subjects lay prone for 15 minutes before being retested. SUBJECTS: Thirty-seven healthy college students (11 men, 26 women, age = 20.46 +/- 1.74 years) volunteered. MEASUREMENTS: Hamstring flexibility was measured using a sit-and-reach box before and after each treatment. RESULTS: The average increases in hamstring flexibility over the 5 treatment days for the diathermy and stretching, stretching-only, and control groups were 6.06 cm (19.6%), 5.27 cm (19.7%), and 3.38 cm (10.4%), respectively. Three days later (after no treatment), the values for the diathermy and stretching, stretching-only, and control groups were 8.27 cm (26.7%), 6.83 cm (25.3%), and 4.15 cm (14.2%), respectively. No significant differences in hamstring flexibility were noted among the groups. CONCLUSIONS: Diathermy and short-duration stretching were no more effective than short-duration stretching alone at increasing hamstring flexibility. The effects of diathermy with longer stretching times need to be researched.
title: Effects of moist heat on hamstring flexibility and muscle temperature.
abstract: The purpose of this study was to determine whether the application of a moist heat pack (MHP) could increase hamstring flexibility. Both legs for each subject were used for this study. Each leg was randomly assigned to either an MHP leg or a control leg condition. Twenty-seven male subjects (height = 178.5 +/- 8.6 cm; weight = 84.4 +/- 18.7 kg; age = 21.9 +/- 6.3 years) volunteered for this study. For the MHP leg condition, baseline hamstring flexibility was measured using an active knee extension test. A 23-ga indwelling thermistor was inserted to a depth of 2.54 cm to measure hamstring temperature. After baseline temperature was recorded, 2 MHPs were placed on either side of the thermistor until temperature was increased by 0.4 degrees C. Hamstring flexibility postintervention measurements were performed at 0, 4, 8, and 16 minutes. The same protocol was used for the control leg, without the MHP application. A 2 x 5 repeated-measures analysis of variance revealed no significant interaction between the MHP and the control leg condition. These results support previous findings that MHP application does not significantly affect muscle flexibility. After application of an MHP, it takes 20-25 minutes to increase intramuscular temperatures by 0.4 degrees C. Both of these findings should be taken into consideration when using an MHP to increase muscle flexibility.
title: Comparison of an indirect tri-planar myofascial release (MFR) technique and a hot pack for increasing range of motion.
abstract: The purpose of the randomized clinical study was to scientifically assess which intervention increases passive range of motion most effectively: the indirect tri-planar myofascial release (MFR) technique or the application of hot packs for gleno-humeral joint flexion, extension, and abduction.
title: Effects of Hot or Cold Water Immersion and Modified Proprioceptive Neuromuscular Facilitation Flexibility Exercise on Hamstring Length.
abstract: OBJECTIVE: To compare the changes in hamstring length resulting from modified proprioceptive neuromuscular facilitation flexibility training in combination with cold-water immersion, hot-water immersion, and stretching alone. DESIGN AND SETTING: Training-only subjects stood motionless for 10 minutes, while subjects in the cold group stood in a cold-water bath (8 degrees +/- 1 degrees C) immersed up to the gluteal fold for 10 minutes, and subjects in the hot group stood in a hot-water bath (44 degrees +/- 1 degrees C) immersed up to the gluteal fold for 10 minutes. All subjects exercised only the right lower limb using a modified proprioceptive neuromuscular facilitation flexibility protocol, consisting of 1 set of 4 repetitions. This procedure was followed for 5 consecutive days. SUBJECTS: Forty-five uninjured subjects (21 women, 24 men; age range, 18-25 years) were randomly assigned to the cold, hot, or stretching-alone group. MEASUREMENTS: Subjects were measured for maximum active hip flexion on the first and fifth days. RESULTS: Group results were assessed using a 2 x 3 analysis of variance, comparing changes in hamstring length from pretest to posttest. All 3 groups had significant improvements in hamstring length (pretest to posttest) (P <.05). However, no significant differences occurred among groups. CONCLUSIONS: No advantage was apparent in using complete hot or cold immersion to increase hamstring length in healthy subjects.
title: The effects of heating with ultrasound on knee joint displacement.
abstract: Heating with continuous wattage ultrasound combined with mobilization procedures is often used to treat ligament "tightness," but the effects of heat on ligament extensibility have not previously been studied in vivo. To address this problem, 25 young adults underwent knee joint displacement tests on a Genucom arthrometer before and after continuous wattage ultrasound (1 MHZ, 1.5 W/cm2 x 8 min). Preultrasound intrarater reliability (ICC; N = 11) was 0.87-0.98 for varus/valgus and recurvatum tests and 0.70-0.73 for anterior-posterior drawer tests.
title: Temperature-dependent viscoelastic properties of the human supraspinatus tendon.
abstract: Temperature effects on the viscoelastic properties of the human supraspinatus tendon were investigated using static stress-relaxation experiments and the quasi-linear viscoelastic (QLV) theory. Twelve supraspinatus tendons were randomly assigned to one of two test groups for tensile testing using the following sequence of temperatures: (1) 37, 27, and 17 degrees C (Group I, n=6), or (2) 42, 32, and 22 degrees C (Group II, n=6). QLV parameter C was found to increase at elevated temperatures, suggesting greater viscous mechanical behavior at higher temperatures. Elastic parameters A and B showed no significant difference among the six temperatures studied, implying that the viscoelastic stress response of the supraspinatus tendon is not sensitive to temperature over shorter testing durations. Using regression analysis, an exponential relationship between parameter C and test temperature was implemented into QLV theory to model temperature-dependent viscoelastic behavior. This modified approach facilitates the theoretical determination of the viscoelastic behavior of tendons at arbitrary temperatures.
title: Shortwave diathermy and prolonged stretching increase hamstring flexibility more than prolonged stretching alone.
abstract: A randomized, counterbalanced 2x3x5 repeated-measures design.
title: Effects of cold and hot water immersion on the mechanical properties of human muscle and tendon in vivo.
abstract: Cooling and heating have been shown to affect the contractile properties of muscles. However, the reasons for these changes remain unclear. The present study aimed to quantify the mechanical properties of muscle and tendon during passive stretch and active contraction, and to investigate the effects of cooling and heating on the mechanical properties of muscle and tendon.
title: The effects of cold application and modified PNF stretching techniques on hip joint flexibility in college males.
abstract: The purpose of the study was to determine the effects of modified Proprioceptive Neuromuscular Facilitation (PNF) flexibility techniques on hip flexion in college males and to determine if local cold application enhances the effectiveness of these techniques. Male subjects (N = 120), with an average age of 21.5 +/- 2.7 years, were randomly assigned to one of four different kinds of stretching treatments with cold or no cold application (15 per group). Range of motion (ROM) in degrees was determined following four stretching techniques: three modified PNF (PCP, 3-PIECP, 3-PIFCP) and a passive stretch (P). Data were analyzed using a 2 (conditions) x 4 (treatments) ANOVA. There were no significant differences in ROM between cold and no cold conditions. Significant differences existed among ROM techniques (p less than .05). Post hoc analyses revealed that the three modified PNF techniques resulted in greater ROM than the passive stretch technique. However, we conclude that cold application does not influence the effectiveness of selected stretching techniques.
title: The effect of heat on tissue extensibility: a comparison of deep and superficial heating.
abstract: To compare the effects of deep heating (shortwave diathermy [SWD]) and superficial heating (hydrocollator packs) on tissue extensibility.
title: Regular stretch does not increase muscle extensibility: a randomized controlled trial.
abstract: The purpose of this randomized controlled trial was to determine whether regular stretch increases hamstring muscle extensibility. Sixty healthy individuals were randomly allocated to an experimental or a control group. The experimental group attended supervised stretch sessions where they stretched the hamstring muscles of a randomly allocated leg for 30 min five times a week for 6 weeks. The control group did not attend any stretch sessions during this period. No participants withdrew from the study. A purpose built device was used to measure passive hip flexion during a straight leg-raise manoeuvre with the application of a standardized and non-standardized stretch torque. The stretch intervention did not increase passive hip flexion when measured with a standardized stretch torque [mean treatment effect=-1 degrees; 95% confidence interval (CI)=-3 to 2 degrees]. It did, however, increase passive hip flexion when measured without a standardized stretch torque (mean treatment effect=10 degrees, 95% CI=6-14 degrees). Six weeks of sustained 30-min daily stretch does not increase the extensibility of the hamstring muscle of healthy individuals. It does, however, improve stretch tolerance leading to increased joint range of motion without any actual improvements in muscle extensibility.
title: Effects of cold water immersion on knee joint position sense in healthy volunteers.
abstract: The purpose of this study was to determine the effects of cryotherapy, in the form of cold water immersion, on knee joint position sense. Fourteen healthy volunteers, with no previous knee injury or pre-existing clinical condition, participated in this randomized cross-over trial. The intervention consisted of a 30-min immersion, to the level of the umbilicus, in either cold (14 ± 1 °C) or tepid water (28 ± 1 °C). Approximately one week later, in a randomized fashion, the volunteers completed the remaining immersion. Active ipsilateral limb repositioning sense of the right knee was measured, using weight-bearing and non-weight-bearing assessments, employing video-recorded 3D motion analysis. These assessments were conducted immediately before and after a cold and tepid water immersion. No significant differences were found between treatments for the absolute (P = 0.29), relative (P = 0.21) or variable error (P = 0.86). The average effect size of the outcome measures was modest (range -0.49 to 0.9) and all the associated 95% confidence intervals for these effect sizes crossed zero. These results indicate that there is no evidence of an enhanced risk of injury, following a return to sporting activity, after cold water immersion.
title: Effect of superficial heat, deep heat, and active exercise warm-up on the extensibility of the plantar flexors.
abstract: Warm-up prior to static stretching enhances muscle extensibility. The relative effectiveness of different modes of warm-up, however, is unknown. The purpose of this study was to evaluate the effectiveness of superficial heat, deep heat, and active exercise warm-up prior to stretching compared with stretching alone on the extensibility of the plantar-flexor muscles.
title: Efficacy of moist heat pack application over static stretching on hamstring flexibility.
abstract: Inadequate flexibility is a contributing factor to muscle injury, especially with respect to the hamstring muscle group. Simple therapeutic regimens capable of increasing hamstring flexibility may reduce the injury potential of athletes with below-average hamstring flexibility or history of injury. This study compared 30 seconds of static stretching with 20 minutes of heat application on hamstring flexibility. A secondary purpose was to determine the relationship between the subjects attitude toward each treatment and the efficacy of treatment. Thirty undergraduate student athletes who were current members of a Midwestern collegiate football team participated in a 2 (treatment: heat vs. stretching) by 2 (coun-terbalanced order: heat first vs. stretching first) repeated-measures design. Results indicated that significant benefits to increase hamstring flexibility could be gained by using moist heat packs in comparison with static stretching despite a perceived attitudinal bias in favor of stretching. These findings may have implications for orthopedic fitness as well as injury prevention for an athlete with prior hamstring injury or inadequate flexibility.
title: Precooling can prevent the reduction of self-paced exercise intensity in the heat.
abstract: This study investigated the effects of precooling on performance and pacing during self-paced endurance cycling in the heat and, further, the effects of cooling on contractile function as a mechanism for performance changes.
title: The effect of heat and stretching on the range of hip motion*.
abstract: Flexion, abduction, and external rotation of the hip joint were recorded in 30 volunteers randomized into three groups of 10. The measurements were taken before, immediately after, and 30 minutes after treatment of heat, stretching and a combination of heat plus stretching. Heat only did not improve the range of motion of the hip joint. Stretching increased flexion and external rotation, and heat plus stretching in combination gave the greatest increase in flexion motion, and also significantly increased abduction. External rotation after stretching treatment, and flexion and abduction after heat plus stretching treatment were still significantly increased after 30 minutes.J Orthop Sports Phys Ther 1984;6(2):110-115.
title: Focal knee joint cooling increases the quadriceps central activation ratio.
abstract: The objective of this study was to evaluate the effects of a 20-min focal knee joint cooling intervention on quadriceps central activation ratio (CAR) in healthy volunteers. A counterbalanced, cross-over study assessed the effects of a focal joint cooling intervention compared with a control condition 3-14 days apart. Eleven healthy volunteers (6 males, 5 females; age 25 +/- 5 years; height 1.71 +/- 0.1 m, mass 77 +/- 21 kg) were included in the final analysis. The joint cooling intervention consisted of two 1.5-litre ice bags applied to the knee joint for 20 min, in one of two counterbalanced sessions, completed 3-14 days apart. In the control session, participants sat quietly between the baseline and 20-min measurements. Quadriceps CAR was assessed at 70 degrees of knee flexion at four instants (baseline, 20, 30, and 45 min). There was a significant treatment x time interaction (F(3,30) = 5.9, P = 0.003) and post hoc analyses revealed that CAR was higher in the focal knee joint cooling session than the control session at 20 min (0.79 +/- 0.12 vs. 0.70 +/- 0.12; t(10) = 3.9, P = 0.003) and 45 min (0.77 +/- 0.10 vs. 0.69 +/- 0.12; t(10) = 3.1, P = 0.01). The CAR tended to be higher during the experimental session than the control session at 30 min (0.79 +/- 0.13 vs. 0.74 +/- 0.11; t(10) = 2.1, P = 0.07).Volitional activation increased following focal knee joint cooling in healthy volunteers.
title: Effects of whole-body cryotherapy (-110 °C) on proprioception and indices of muscle damage.
abstract: The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (T(TY) ). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of -110 ± 3 °C or 15 ± 3 °C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and T(TY) were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72h post-treatment. WBC reduced T(TY) , by 0.3 °C, when compared with the control group (P<0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC.