The Effects of a Transition to Minimalist Shoe Running on Intrinsic Foot Muscle Size.

A proposed benefit of minimalist shoe running is an increase in intrinsic foot muscle strength. This study examined change in intrinsic foot muscle size in runners transitioning to Vibram FiveFingers™ minimalist shoes compared to a control group running in traditional running shoes. We compare pre-transition size between runners who developed bone marrow edema to those who did not. 37 runners were randomly assigned to the Vibram FiveFingers™ group (n=18) or control group (n=19). Runners' bone marrow edema and intrinsic foot muscle size were measured at baseline and after 10 weeks. Total running volume was maintained by all runners. A significant increase in abductor hallucis cross-sectional area of 10.6% occurred in the Vibram FiveFingers™ group compared to the control group (p=0.01). There was no significant change in any of the other muscles examined (p>0.05). 8 of the Vibram FiveFingers™ runners, and 1 control runner developed bone marrow edema. Those who developed bone marrow edema, primarily women, had significantly smaller size in all assessed muscles (p≤0.05). Size of intrinsic foot muscles appears to be important in safely transitioning to minimalist shoe running. Perhaps intrinsic foot muscle strengthening may benefit runners wanting to transition to minimalist shoes.

Ten-year cardiovascular risk assessment in university students.

Cardiovascular disease (CVD) is responsible for more than half of all deaths in the European region. The aim of the study was to compare body composition, blood pressure, total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C), family history, activity behaviors, and the 10-year risk of having a heart attack between 166 university students (21.62 ± 2.59 yrs) from Utah (USA) and 198 students (22.11 ± 2.51 yrs) from Hungary. Ninety-two percent of the Hungarian students and 100% of the Utah students had an estimated 10-year Framingham risk score of 1% or less. The high prevalence of low risk was primarily due to the young age of study participants, healthy body composition and non-smoking behavior. Hungarians who had higher 10-year risk of heart attack had significantly higher waist hip ratio (WHR), TC, diastolic blood pressure (DBP) and were smokers compared to those Hungarians with lower risk. The self-reported physical activity levels between the two groups of students were not different. In conclusion the young men and women who participated in this study were, for the most part healthy; however the smoking habits and the lower physical activity of the Hungarian students likely elevated their risk of CVD.

The effect of duration of stretching of the hamstring muscle group for increasing range of motion in people aged 65 years or older.

BACKGROUND AND PURPOSE: Stretching protocols for elderly people (> or = 65 years of age) have not been studied to determine the effectiveness of increasing range of motion (ROM). The purpose of this study was to determine which of 3 durations of stretches would produce and maintain the greatest gains in knee extension ROM with the femur held at 90 degrees of hip flexion in a group of elderly individuals. SUBJECTS: Sixty-two subjects (mean age = 84.7 years, SD = 5.6, range = 65-97) with tight hamstring muscles (defined as the inability to extend the knee to less than 20 degrees of knee flexion) participated. Subjects were recruited from a retirement housing complex and were independent in activities of daily living. METHODS: Subjects were randomly assigned to 1 of 4 groups and completed a physical activity questionnaire. The subjects in group 1 (n = 13, mean age = 85.1 years, SD = 6.4, range = 70-97), a control group, performed no stretching. The randomly selected right or left limb of subjects in group 2 (n = 17, mean age = 85.5 years, SD = 4.5, range = 80-93), group 3 (n = 15, mean age = 85.2 years, SD = 6.5, range = 65-92), and group 4 (n = 17, mean age = 83.2 years, SD = 4.6, range = 68-90) was stretched 5 times per week for 6 weeks for 15, 30, and 60 seconds, respectively. Range of motion was measured once a week for 10 weeks to determine the treatment and residual effects. Data were analyzed using a growth curve model. RESULTS: A 60-second stretch produced a greater rate of gains in ROM (60-second stretch = 2.4 degrees per week, 30-second stretch = 1.3 degrees per week, 15-second stretch = 0.6 degrees per week), which persisted longer than the gains in any other group (group 4 still had 5.4 degrees more ROM 4 weeks after treatment than at pretest as compared with 0.7 degrees and 0.8 degrees for groups 2 and 3, respectively). DISCUSSION AND CONCLUSION: Longer hold times during stretching of the hamstring muscles resulted in a greater rate of gains in ROM and a more sustained increase in ROM in elderly subjects. These results may differ from those of studies performed with younger populations because of age-related physiologic changes.

Exercise after cryotherapy greatly enhances intramuscular rewarming.

OBJECTIVE: To determine the effect of moderate-intensity walking on rewarming of the triceps surae muscle group after a 20-minute application of a crushed-ice pack. DESIGN AND SETTING: Subjects were randomly assigned to either the ice-rest or the ice-exercise group. All subjects were treated on the left calf for 20 minutes with a 1.8-kg ice pack. The ice-exercise group walked on a treadmill at 5.63 km/h for 10 minutes and then assumed a prone position on an examining table for 20 minutes. The ice-rest group assumed a prone position on an examining table for 30 minutes after the cryotherapy treatment. SUBJECTS: Twenty-eight (19 men and 9 women) college-student volunteers. MEASUREMENTS: Intramuscular temperature was recorded at 10-second intervals for 50 minutes at 1 cm below the subcutaneous fat with a thermocouple implanted via a 21-gauge sterile hypodermic needle. Differences were analyzed within and between groups at pretreatment (T(0)), the end of the ice treatment (T(20)), 11 minutes after the end of ice treatment (T(31)), and 30 minutes posttreatment (T(50)). RESULTS: We found no differences at T(0) and T(20) but significant differences at T(31) and T(50). At T(31), the ice-exercise group was only 0.61 degrees C colder than at pretreatment levels, while the ice-rest group was 8.05 degrees C colder. By T(50), the temperatures were 0.93 degrees C and 6.95 degrees C colder, respectively, than at pretreatment levels. CONCLUSION: Moderate walking significantly enhanced rewarming of the triceps surae.

Temperature changes in the human leg during and after two methods of cryotherapy.

OBJECTIVE: To compare the cooling and rewarming effects of two clinical 20-minute cryotherapy treatments on the temperature of the human leg. DESIGN AND SETTING: Sixteen subjects were randomly treated with either 20 minutes of a 1.8-kg crushed-ice pack, placed directly over the left calf, or a 20-minute immersion in a cold (10 degrees C) whirlpool. Data were collected at a university human performance research laboratory. SUBJECTS: Seventeen male and 15 female healthy college students. MEASUREMENTS: Subcutaneous and muscle tissue temperatures were measured by 26-gauge hypodermic needle microprobe inserted in the calf, just below the skin, or 1 cm below the subcutaneous fat, respectively. RESULTS: There was no significant difference in the decrease in intramuscular temperatures between treatments (t (30) = -1.76, P = .09). The ice pack treatment significantly decreased the subcutaneous temperature more than the whirlpool (t (30) = -2.64, P = .01). The subcutaneous temperature rewarmed significantly more in the ice pack group (12.3 +/- 3.3 degrees C) than the cold whirlpool (7.4 +/- 2.1 degrees C) (t (30) = 4.98, P = .0000). The ice pack group's intramuscular temperature increased over each 5-minute interval of the 30-minute post-treatment period for an overall increase of 2.0 +/- 3.1 degrees C. During the 30-minute post- treatment the cold whirlpool group continued to cool, for an overall decrease of 1.8 +/- 1.4 degrees C. This difference between groups at the end of the 30-minute post-treatment was significant (t(30) = 4.44, P = .0001). CONCLUSIONS: As administered in our protocol, cold whirlpool is superior to crushed-ice packs in maintaining prolonged significant temperature reduction after treatment.

Temperature changes in human patellar tendon in response to therapeutic ultrasound.

OBJECTIVE: To determine the rate and magnitude of temperature change in response to ultrasound in human patellar tendon for two treatment sizes. DESIGN AND SETTING: A thermistor was inserted into the medial aspect of each subject's right patellar tendon, and the baseline temperature was recorded. Using stratified random sampling and using a transducer head with an effective radiating area (ERA) of 4.5 cm(2), we had eight subjects each undergo either the 2-or 4-ERA ultrasound treatment first. Each subject received a 3-MHz continuous ultrasound treatment at 1 W/cm(2) for both the 2-and 4-ERA treatment sizes. SUBJECTS: Sixteen subjects (8 males, 21.3 +/- 1.9 years, and 8 females, 21.0 +/- 2.8 years) participated. MEASUREMENTS: We moved the sound head at a speed of 2 to 3 cm/sec while recording the tendon temperature every 30 seconds during, and for 20 minutes after, the 4-minute treatment. Twenty minutes after the treatment, we applied the second treatment to the other ERA treatment size. RESULTS: At the end of the treatment, the mean temperature increase was significantly different (P = .006) between treatment sizes (8.3 degrees C +/- 1.7 degrees C (2 x ERA) and 5.0 degrees C +/- 1.0 degrees C (4 x ERA)). The rate of increase was also significantly different (P < .001). The heating rate per minute for the 2-ERA treatment was 2.1 degrees C +/- 0.4 degrees C and 1.3 degrees C +/- 0.3 degrees C for the 4-ERA treatment. There was a significant difference in the cooling between treatment sizes (P = .001). The rate of temperature decrease between treatment sizes was significantly different only during the first 5-minute interval post-treatment. CONCLUSION: Three-megahertz ultrasound at an intensity of 1 W/cm(2) significantly increased patellar tendon temperature at both 2 and 4 x ERA, but our results confirm that the 2-ERA treatment size provided higher and longer heating than the 4-ERA treatment size.

Temperature rise in human muscle during ultrasound treatments using flex-all as a coupling agent.

OBJECTIVE: To determine if Flex-all 454, as advertised, is effective as a thermal ultrasound couplant. DESIGN AND SETTING: Research design was a one-factor analysis of variance. Subjects received three (alternating order) ultrasound treatments (1 MHz at 1.5 W/cm(2) for 10 minutes) using the following couplants: 50% Flex-all mixed with 50% ultrasound gel; 100% ultrasound gel; and sham ultrasound with 100% Flex-all. Data were collected in a ventilated laboratory. SUBJECTS: Fifteen male and female students (mean age = 24.2 +/- 3.7 years). MEASUREMENTS: Muscle temperature was measured via hypodermic microprobes inserted 3 and 5 cm deep in the medial triceps surae. A visual analogue scale was used to measure perceived heat. RESULTS: At 3 cm, the increases for the gel, 50/50 mixture, and sham were 3.2 degrees C, 2.6 degrees C, and -0.82 degrees C, respectively. At 5 cm, the increases were 2.17 degrees C, 1.80 degrees C, and -0.50 degrees C, respectively. Subjects rated the sham treatment as mild heating (although the temperature dropped) and perceived treatments using the 50/50 mixture to be warmer than treatments using 100% gel couplant. CONCLUSION: Ultrasound treatments delivered with a 50/50 Flex-all/gel couplant felt warmer to subjects; however, identical treatments with 100% ultrasound gel produced higher muscle temperatures. Clinicians desiring optimal thermal effects should use 100% ultrasound gel as the couplant.

An electromyographic investigation of 4 elastic-tubing closed kinetic chain exercises after anterior cruciate ligament reconstruction.

OBJECTIVE: To determine the electromyographic (EMG) activity of the vastus medialis oblique (VMO), vastus lateralis (VL), semitendinosus and semimembranosus (ST), and biceps femoris (BF) muscles during 4 elastic-tubing closed kinetic chain exercises in postoperative patients with anterior cruciate ligament (ACL)-reconstructed knees. DESIGN AND SETTING: A 4 x 4 repeated-measures analysis of variance design guided this study. Independent variables were type of exercise and muscle; the dependent variable was EMG activity. SUBJECTS: Fifteen patients, 5 to 24 weeks after ACL reconstruction. MEASUREMENTS: Subjects performed 4 exercises (front pull, back pull, crossover, reverse crossover) with elastic tubing attached to the foot of the uninjured leg. Time-and amplitude- normalized EMG activity was recorded from the VMO, VL, ST, and BF muscles of the injured leg. The hamstrings: quadriceps ratio was calculated. RESULTS: The normalized VMO, VL, and BF EMG activity ranged from 25% to 50% of maximum voluntary isometric contraction for the 4 exercises. The ST ranged from 12% on the back pull to 58% on the front pull. The hamstrings: quadriceps ratios were 137% (front pull), 115% (crossover), 70% (back pull), and 60% (reverse crossover). CONCLUSIONS: We suggest that clinicians use these exercises during early ACL rehabilitation since they incorporate early weightbearing with hamstring and quadriceps coactivation.

Cold- and hot-pack contrast therapy: subcutaneous and intramuscular temperature change.

OBJECTIVE: To investigate the temperature changes in subcutaneous and intramuscular tissue during a 20-minute cold- and hot-pack contrast therapy treatment. DESIGN AND SETTING: Subjects were randomly exposed to 20 minutes of contrast therapy (5 minutes of heat with a hydrocollator pack followed by 5 minutes of cold with an ice pack, repeated twice) and 20 minutes of cold therapy (ice pack only) in a university laboratory. SUBJECTS: Nine men and seven women with no history of peripheral vascular disease and no allergy to cephalexin hydrochloride volunteered for the study. MEASUREMENTS: Subcutaneous and intramuscular tissue temperatures were measured by 26-gauge hypodermic needle microprobes inserted into the left calf just below the skin or 1 cm below the skin and subcutaneous fat, respectively. RESULTS: With contrast therapy, muscular temperature did not fluctuate significantly over the 20-minute period compared with the subcutaneous temperature, which fluctuated from 8 degrees C to 14 degrees C each 5-minute interval. When subjects were treated with ice alone, muscle temperature decreased 7 degrees C and subcutaneous temperature decreased 17 degrees C over the 20-minute treatment. CONCLUSIONS: Our results show that contrast therapy has little effect on deep muscle temperature. Therefore, if most of the physiologic effects attributed to cold and hot contrast therapy depend on substantial fluctuations in tissue temperature, contrast therapy needs to be reconsidered as a viable therapeutic modality.

The effects of high-volt pulsed current electrical stimulation on delayed-onset muscle soreness.

OBJECTIVE: We investigated three 30-minute high-volt pulsed current electrical stimulation (HVPC) treatments of 125 pps to reduce pain, restore range of motion (ROM), and recover strength loss associated with delayed-onset muscle soreness (DOMS). DESIGN AND SETTING: Randomized, masked comparison of three 30-minute treatment and sham HVPC regimens over a 48-hour period. SUBJECTS: Twenty-eight college students. MEASUREMENTS: Subjects performed concentric and eccentric knee extensions with the right leg to induce muscle soreness. Assessments were made before and after the exercise bout and each treatment at 24, 48, and 72 hours postexercise. RESULTS: Three separate 2 x 3 x 2 ANOVAs were used to determine significant differences (p < .05) between days, treatments, and pre-post treatment effects and significant interaction among these variables. Scheffe post hoc tests showed no significant reduction in pain perception or improvement in loss of function at 24, 48, and 72 hours postexercise. Mean pain perception assessments (0 = no pain, 10 = severe pain) for the HVPC group were 2.9, 4.5, and 3.5 and for the sham group 3.8, 4.8, and 3.5). Mean ROM losses for the HVPC group were 9.0 degrees , 22.3 degrees , and 26.2 degrees , and for the sham group were 9.5 degrees , 23.1 degrees , and 23.0 degrees . Mean strength losses (1RM) for the HVPC group were 25.9, 25.7, and 20.8 lbs and for the sham group were 22.3, 22.3, and 13.8 lbs. CONCLUSIONS: HVPC as we studied it was ineffective in providing lasting pain reduction and at reducing ROM and strength losses associated with DOMS.

Relative and absolute reliability of the KT-2000 arthrometer for uninjured knees. Testing at 67, 89, 134, and 178 N and manual maximum forces.

We assessed the reliability of the KT-2000 knee arthrometer at 67, 89, 134, and 178 N and at manual maximum forces on 30 college students who were free from present or previous knee injuries. Two examiners tested all subjects on two occasions. Anterior laxity (P < 0.0001) and side-to-side difference (P < 0.05) significantly increased as force increased. There was a significant difference (P < 0.0001) between testers for anterior laxity but not for side-to-side difference. We used intraclass correlation coefficients to estimate relative reliability. Anterior laxity intraclass correlation coefficients (2,1) between testers ranged from 0.81 to 0.86 and within tester correlations ranged from 0.92 to 0.95. Intraclass correlation coefficients for between testers for side-to-side differences ranged from 0.38 to 0.58 and within tester correlations ranged from 0.53 to 0.64. Subject-to-subject variability needs to be taken into account when interpreting intraclass correlation coefficient values. Our absolute reliability estimates (95% confidence intervals) were small, indicating little variability. Our data demonstrate the KT-2000 arthrometer to be reliable. Researchers should present both relative and absolute reliability estimates, although we believe absolute estimates are of greater clinical value. Side-to-side differences are better discriminators than individual absolute values. We recommend that a < 3 mm side-to-side difference be used to indicate stable knees.

A comparison of anterior knee laxity in female intercollegiate gymnasts to a normal population.

Increased joint laxity may predispose an individual to ligamentous injury. Female gymnasts have a high incidence of ligamentous injury, including the anterior cruciate ligament (ACL). Previous authors have found a relationship between ACL disruption and preexisting ligament laxity. The purpose of this study was to compare anterior knee laxity in the knees of female intercollegiate gymnasts with those of a normal female population. A secondary purpose was to measure genu recurvatum and assess the relationship between it and anterior laxity in the knee. We tested 30 gymnasts and 30 control subjects having no history of ACL injury with the KT-1000 knee arthrometer. The quadriceps active, 133 N (30 lb) anterior drawer, and manual maximum tests were performed on the subjects' right knees along with goniometer measurements. Using a two-way analysis of variance (ANOVA) with repeating measures, we detected a significant increase in anterior laxity when comparing the 133 N to the manual maximum test, but no significant difference between gymnasts and nongymnasts. We concluded that gymnasts, as a group, are not abnormally lax when compared to an active population of similar age. Future comparison of the longitudinal data of those who incur ACL injury during their gymnastics careers may show whether individuals with increased laxity have increased risk of ligamentous injury.

Contrast therapy and intramuscular temperature in the human leg.

Contrast therapy, although having a long history of use in sports medicine and physical therapy, remains insufficiently researched. We investigated the thermal effects of contrast therapy on intramuscular temperature. We randomly assigned 28 college students to either a control or a contrast group, eight women and six men per group. We shaved and cleansed a 4- x 4-cm area of skin over the right medial calf and inserted a microprobe to a depth of 1 cm below the skin and subcutaneous fat in the center of the gastrocnemius. Each control subject immersed the treatment leg in a hot whirlpool (40.6 degrees C) for 20 minutes. Each contrast subject first immersed the treatment leg in a hot whirlpool (40.6 degrees C) for 4 minutes then into a cold whirlpool (15.6 degrees C) for 1 minute. Contrast subjects repeated this sequence three additional times. We recorded intramuscular temperatures every 30 seconds over the entire treatment time for both groups. The control group had a temperature increase of 2.83 +/- 1.14 degrees C over the 20-minute treatment. The contrast group temperature increased 0.39 +/- 0.46 degrees C from baseline to the end of the treatment. The largest temperature change from the end of one contrast immersion to the end of the next was only 0.15 +/- 0.10 degrees C. None of the differences between the end of one immersion to the end of the next were significant. Conversely, all differences between the same time periods in the control group had significant temperature increases. Apparently contrast therapy, as studied, is incapable of producing any significant physiological effect on the intramuscular tissue temperature 1 cm below the skin and subcutaneous tissue. We recommend that further research be done to examine the effects of longer periods in both the hot and cold environments on the intramuscular temperature of the human leg. Further investigation of intra-articular or peri-articular temperature change produced by contrast therapy should also be undertaken.

Cryotherapy and sequential exercise bouts following cryotherapy on concentric and eccentric strength in the quadriceps.

We investigated the effects of cryotherapy followed by sequential exercise bouts on concentric and eccentric strength of the quadriceps. Nineteen males (18-27 years) participated in a two-stage design involving four sequences: ice and exercise, ice and rest, no ice and exercise, and no ice and rest. We gathered concentric and eccentric strength measures (torque) using a kinetic communicator (KIN-COM) prior to exercise, immediately following treatment, and 20- and 40-minutes post-treatment. There were significant decreases in concentric and eccentric strength immediately following the 25-minute cryotherapy treatment. This suggests that applying ice immediately prior to participation or returning an athlete to competition immediately following cryotherapy treatment may adversely affect his/her ability to perform. It appears that the reduction in strength following cryotherapy is of short duration (less than 20 minutes). The delayed effect of the ice treatment and sequential exercise appears to affect concentric and eccentric strength differently. Ice did not have a delayed effect on concentric strength, but there was a significant difference in eccentric values. This difference was a failure to improve during post-tests at the rate of those not treated with ice. Exercise did not have a significant effect on eccentric strength recovery, but there was a significant difference in concentric values. Moderate exercise following cryotherapy appears to help the recovery of concentric strength.

Topically applied dimethyl sulfoxide. Its effects on inflammation and healing of a contusion.

This study investigated the effects of topically applied dimethyl sulfoxide (DMSO) to traumatized muscle of adult male rats. Eighty rats were randomly assigned to one of two groups and subsequently traumatized, treated, and sacrificed. One group was used to examine inflammation; the other, healing. Each group was further divided into an experimental group (70% DMSO and 30% distilled water) and a control group (100% distilled water); each group had five sacrifice times. Each treatment consisted of painting 1 ml of either the treatment or control solution on the contused tissue. The inflammation group received 15 additional treatments, 3 per day for the next 5 days. A three-phased, single blind, histologic examination was performed. The principle findings were: significantly fewer healing cells were present in the experimental group than in the control group during the period inflammation was examined, and no significant difference existed between the experimental and control groups during the period healing was examined.