Assessing the differences in muscle stiffness measured with shear wave elastography and myotonometer during the menstrual cycle in young women.

This study assessed the differences in muscle stiffness of the medial gastrocnemius (MG) and tibialis anterior (TA) muscles at rest and contraction during ovulation and follicular phase (menstruation) in women with regular menstrual cycle. Thirty-four young healthy women (mean age 21.3 ± 1.3 years) with regular menstrual cycles participated in this study. Stiffness of the TA and MG muscles at rest and voluntary contraction during ovulation and follicular phase in young women were measured using shear-wave elastography (SWE) and the handheld myotonometer MyotonPRO. The absolute stiffness difference between resting and contraction was expressed as the stiffness increase rate (SIR). The stiffness of the MG and TA at the resting position was not significantly different between the two phases of the menstrual cycle (p > 0.05). A significantly greater stiffness of both muscles measured using MyotonPRO in the follicular phase than during ovulation was found (p < 0.05), while stiffness measured by SWE showed a difference only in the TA muscle during contraction (p < 0.05). In addition, there were no significant differences in the SIR of both muscles between the two phases (p > 0.05). The results of our study showed a significantly greater stiffness of the MG and TA muscles at the follicular phase than at ovulation during contraction only. As muscle stiffness affects the risk of injury owing to reduced stability during sports activities, these changes in mechanical properties during the menstrual cycle should be noted, and training strategies should be used in female athletes.

Neuromuscular Control of Ankle-stabilizing Muscles-specific Effects of Sex and Menstrual Cycle.

The purpose of this study was to examine the differences in neuromuscular control and mechanical properties of the ankle-stabilizing muscles between men and women, and during different phases of menstrual cycle in women. Fifteen women with regular menstrual cycles and 17 male counterparts were included in this study. Electromyographic signals were recorded from the peroneus longus (PL) and tibialis anterior (TA) muscles while performing three balance tasks. Muscle tone, stiffness, and elasticity of muscles were measured using a MyotonPRO in the resting position. Outcomes were measured twice (ovulation and early follicular phases) for women, while measurements were acquired only once for men. Significantly higher tibialis anterior-peroneus longus co-contraction (TA/PL ratio) was observed in all balance tasks in women than in men (p< 0.05); however, significant differences between phases of the menstrual cycle were noted only in the 2 most difficult tasks (p< 0.05). A similar pattern was observed in the postural sway. These results highlight the importance of sex-specific hormonal effects on neuromuscular control and mechanical properties, and as well as the differences during phases of the menstrual cycle. These insights assume significance in the context of developing neuromuscular strategies for the purpose of preventing lower extremity injuries during sports activities.

Stress Incontinence during Different High-Impact Exercises in Women: A Pilot Survey.

The aim of this survey was to investigate the prevalence of stress urinary incontinence (SUI) among women (primigravida, multigravida, and nulligravida) in high-impact exercise groups-CrossFit, kickboxing, and boot camp. Incontinence Survey was modified to an anonymous online questionnaire. A total of 17 participants, 64.2% reported at least some urinary leakage during exercise. About 85.7% of participants in each of the 3 high-intensity exercise groups exercised >3 h/week. There was no significant difference in the likelihood of urinary leakage between participants who have had at least 1 pregnancy and those who had never been pregnant. CrossFit group were significantly more likely to report urinary leakage than those in the kickboxing and boot camp groups combined (p = 0.023). The participants did not exhibit typical risk factors, as they were premenopausal, active, and had an average body mass index within the normal range. This pilot survey indicates that all women those who do high-impact exercises are susceptible to stress urinary incontinence (SUI), and that CrossFit poses a greater risk for SUI in terms of more jumping resulting in increased intra-abdominal pressure and ground reaction forces compared to others. Our pilot study indicates that a higher risk of SUI during high impact exercises may exist associated with previous pregnancy but also in nulliparous women.

Gender-specific differences of normative values of pelvic floor muscle function in healthy adults population: an observational analytical study.

Females and males differ significantly in gross anatomy and physiology of the pelvic floor muscle, and these differences are commonly discussed in the scientific literature. However, less attention is dedicated to investigating the normative values of pelvic floor muscle (PFM) function between females and males. Our study aims to describe the normal reference values of PFM function in females and males of a healthy adult population using transabdominal ultrasound (TAUS). A total of 200 healthy adults, including 71 males and 129 females consented to participate in this study. Bladder base displacement was measured using a sagittal curved linear array 2-5 MHz transducer over the suprapubic region. The amount of bladder base movement on ultrasound was measured in all subjects from freeze frame ultrasound images and considered as an indicator of PFM function. The average age of subjects was (26.1 ± 2.6 years), (24.4 ± 3.7 BMI). Statistical analysis revealed a significant difference in transabdominal ultrasound measurement for PFM function (p = .00000). The bladder base displacement was significantly greater in males compared to females (0.65 ± 0.42 vs. 0.38 ± 0.35, p <.001, 95% CI:0.16-0.38). The present study provides evidence of a gender-related PFM functional differences creating a baseline for the clinic to establish the normal percentile values of PFM function.

Use of low level of continuous heat and Ibuprofen as an adjunct to physical therapy improves pain relief, range of motion and the compliance for home exercise in patients with nonspecific neck pain: A randomized controlled trial.

BACKGROUND: It has been well documented at heat reduces pain and increases healing by increasing blood flow in tissue. OBJECTIVE: The purpose of this study was to see if the use of low level continuous heat (LLCH) and Ibuprofen used as a home therapy between physical therapy sessions at a clinic resulted in better therapy outcomes in people with chronic neck pain. METHODS: Ninety-two patients with chronic nonspecific neck pain were randomly divided into 4 groups; LLCH group, LLCH with Ibuprofen (IP) group, sham LLCH with sham IP group, and controls. All subjects underwent 45 minutes of conventional physical therapy twice a week for 2 weeks. the neck disability index (NDI), subjective pain, range of motion (ROM), strength of the neck, and home exercise compliance were measured. RESULTS: Both LLCH and IP significantly reduced pain and NDI score, and increased ROM (p< 0.01). Home exercise compliance in LLCH and LLCH with IP group was significantly higher than the placebo and control groups (p < 0.05). CONCUSION: The use of LLCH alone and LLCH with IP as an adjunct to conventional physical therapy for chronic neck pain significantly improved pain attenuation and it causes greater compliance for home.

Sudomotor and vasomotor activity during the menstrual cycle with global heating.

Many studies have reported that there are changes in sympathetic activity throughout the menstrual cycle as there are oestrogen receptor in the hypothalamus and all other parts of the sympathetic nervous system. The purpose of this study was to see whether there were variations in sympathetic activity, skin vasomotor and sweat gland sudomotor rhythms during the menstrual cycle. Eight young female subjects with a regular menstrual cycle participated in the study. Subjects were tested once during the follicular phase and once during the luteal phase. Skin blood flow and sweat rate were significantly higher in the luteal phase compared with the follicular phase (p < .05), but the frequency and magnitude of sudomotor and vasomotor rhythms were significantly greater in the follicular phase (p < .05). In contrast, spectral data showed less sympathetic activity in the luteal phase. A significant finding here is that the sudomotor rhythm of sweat glands is altered by the menstrual cycle.

The Efficacy of Sustained Heat Treatment on Delayed-Onset Muscle Soreness.

OBJECTIVE: To assess the impact of heat applied for 8 hours immediately after or 24 hours after exercise on delayed-onset muscle soreness (DOMS) in large skeletal muscle groups measured by subjective and objective means. DESIGN: Cross-sectional repeated measure design study. SETTING: Research laboratory. SUBJECTS: Three groups of 20 subjects, age range 20 to 40 years. INTERVENTION: Squats were conducted in three 5-minute bouts to initiate DOMS; 3 minutes of rest separated the bouts. One group had heat applied immediately after exercise, and a second group had heat applied 24 hours after exercise. A third group was the control group where no heat was applied. MAIN OUTCOME MEASURES: Visual analog pain scales, muscle strength of quads, range of motion of quads, stiffness of quads (Continuous Passive Motion machine), algometer to measure quadriceps soreness, and blood myoglobin. RESULTS: The most significant outcome was a reduction in soreness in the group that had low-temperature heat wraps applied immediately after exercise (P < 0.01). There was benefit to applying heat 24 hours after exercise, but to a smaller extent. This was corroborated by myoglobin, algometer, and stiffness data. CONCLUSIONS: Low-level continuous heat wraps left for 8 hours just after heavy exercise reduced DOMS in the population tested as assessed by subjective and objective measures. CLINICAL RELEVANCE: Although cold is commonly used after heavy exercise to reduce soreness, heat applied just after exercise seems very effective in reducing soreness. Unlike cold, it increases flexibility of tissue and tissue blood flow. For joint, it is still probably better to use cold to reduce swelling.

Cold Vs. Heat After Exercise-Is There a Clear Winner for Muscle Soreness.

Because of the differences in the exercise type, temperature, and timing of the use of cold and heat after exercise in different studies, there is no clear conclusion as to the efficacy of either modality on reducing delayed onset muscle soreness. One hundred subjects at similar fitness levels were examined. They accomplished leg squats for 15 minutes and heat and cold were applied after or 24 hours after exercise using ThermaCare heat or cold wraps. Measurements obtained were strength, the force to passively move the knee, analog visual pain scales, and blood myoglobin. Control subjects lost 24% strength after exercise. Subjects with heat or cold just after exercise only lost 4% strength (p < 0.01). For strength recovery, cold applied after 24 hours was better than heat at 24 hours. Heat or cold applied after exercise was significantly better to prevent elastic tissue damage (p < 0.01), whereas heat and cold immediately after exercise caused no loss in muscle myoglobin and heat or cold after 24 hours showed no less muscle damage from myoglobin than in control subjects. Myoglobin in the control and heat and cold 24-hour groups averaged 135.1% of the baseline data but averaged 106.1% of baseline in the immediate heat and cold groups. For reducing pain, control subjects showed a significant amount of pain the days after exercise. But cold immediately after exercise or 24 hours later was superior to heat in reducing pain. In conclusion, both cold and heat appear to be efficacious in reducing muscle damage after exercise.

Six Weeks Habituation of Simulated Barefoot Running Induces Neuromuscular Adaptations and Changes in Foot Strike Patterns in Female Runners.

BACKGROUND: The aim of this study was to examine the effects of a 6-week training program of simulated barefoot running (SBR) on running kinetics in habitually shod (wearing shoes) female recreational runners. MATERIAL AND METHODS: Twelve female runners age 25.7 ± 3.4 years gradually increased running distance in Vibram FiveFingers minimal shoes over a 6-week period. The kinetic analysis of treadmill running at 10 Km/h was performed pre- and post-intervention in shod running, non-habituated SBR, and habituated SBR conditions. Spatiotemporal parameters, ground reaction force components, and electromyography (EMG) were measured in all conditions. RESULTS: Post-intervention data indicated a significant decrease across time in the habituation SBR for EMG activity of the tibialis anterior (TA) in the pre-activation and absorptive phase of running (P<0.001). A significant increase was denoted in the pre-activation amplitude of the gastrocnemius (GAS) between the shod running, unhabituated SBR, and habituated SBR. Six weeks of SBR was associated with a significant decrease in the loading rates and impact forces. Additionally, SBR significantly decrease the stride length, step duration, and flight time, and stride frequency was significantly higher compared to shod running. CONCLUSIONS: The findings of this study indicate that changes in motor patterns in previously habitually shod runners are possible and can be accomplished within 6 weeks. Non-habituation SBR did not show a significant neuromuscular adaptation in the EMG activity of TA and GAS as manifested after 6 weeks of habituated SBR.

17ß-Estradiol Induced Effects on Anterior Cruciate Ligament Laxness and Neuromuscular Activation Patterns in Female Runners.

BACKGROUND: We investigate the effects of 17ß-Estradiol across phases of menstrual cycle on the laxness of the anterior cruciate ligament (ACL) and the neuromuscular control patterns around the knee joint in female runners. METHODS: Twelve healthy female runners who reported normal menstrual cycles for the previous 6 months were tested twice across one complete menstrual cycle for serum levels of 17ß-estradiol, and knee joint laxity (KJL). Electromyographic (EMG) activity of the quadriceps and hamstrings muscles was also recorded during running on a treadmill. The changes in the EMG activity, KJL, and hormonal concentrations were recorded for each subject during the follicular and the ovulatory phases across the menstrual cycle. RESULTS: An observed increase in KJL in response to peak estradiol during the ovulatory phase was associated with increased preactivity of the hamstring muscle before foot impact (p<0.001). A consistent pattern was also observed in the firing of the quadriceps muscle recruitment pattern throughout the follicular phase associated with decreased hamstring recruitment pattern during weight acceptance phase of running (p=0.02). Additionally, a low ratio of medial to lateral quadriceps recruitment was associated with a significant reduction of the quadriceps to hamstring co-contraction ratio during the follicular phase. CONCLUSIONS: Changes in KJL during the menstrual cycle in response to 17ß-estradiol fluctuations changes the neuromuscular control around the knee during running. Female runners utilize different neuromuscular control strategies during different phases of the menstrual cycle, which may contribute to increased ACL injury risk.

Postural sway and motor control in trans-tibial amputees as assessed by electroencephalography during eight balance training tasks.

BACKGROUND: The purpose of this study was to investigate the changes in the Power Spectral Density (PSD) of the electroencephalogram (EEG) during 8 common sensorimotor balance training tasks of varying difficulty in single-limb trans-tibial amputees. MATERIAL AND METHODS: Eight sensorimotor balance exercises, including alteration in vision, base of support, and surface compliance, were used to test postural control and how it related to the electroencephalogram (EEG). A control group was compared to a group of people with trans-tibial amputation of 1 leg to see how the brain responds to loss of a single limb during progressively harder balance testing. Postural sway and EEG changes of the alpha, beta, and sigma wave bands were measured in 20 participants (10 controls, 10 amputees) during 8 balance tasks of varying difficulty with eyes open and closed, feet in tandem or apart, and on a foam or a firm surface. RESULTS: The power of alpha, beta, and sigma bands increased significantly in most tests when comparing the amputees to the control subjects. Balance was significantly worse in the amputees even when standing on both legs. In amputees, balance required more cortical activity than in the controls. CONCLUSIONS: This study demonstrated that amputees have considerably more difficulty in motor control for the brain during balance tasks. Balance was impaired even when standing feet apart on 2 legs and EEG showed more spectral power in all areas of the brain in the amputees.

Anterior cruciate ligament elasticity and force for flexion during the menstrual cycle.

BACKGROUND: A high occurrence of knee injuries have been observed in women during the menstrual cycle (MC). As a result, numerous studies have been conducted regarding knee ligament elasticity during the MC. Some researchers believe that since estrogen receptor b exists in ligaments and tendons in the knee, estrogen may modulate towards a state of laxity. However, increased tissue temperature also observed during the MC can predispose ligament and tendon laxness. Therefore, the purpose of this study was to assess in women the relationship between Estradiol (E2) serum concentrations and tissue temperature during the MC and their combined effect on knee laxity. MATERIAL AND METHODS: Ten non-athletic young healthy females, 18 to 30 years of age participated in the study. E2 serum concentrations, anterior cruciate ligament (ACL) elasticity, and force to flex the knee (FFK), knee flexion-extension hysteresis (KFEH) were assessed both at ambient temperature (22 °C) and after 38 °C warming. Testing was performed multiple times during the participant's MC, for one full MC. RESULTS: ACL elasticity was significantly higher (P<0.01) and FFK and KFEH were significantly lower (p<0.05) during ovulation when E2 levels were highest. ACL elasticity was still higher during ovulation after warming to 38 °C. But, the effects of MC on FFK and KFEH were reduced by tissue warming. CONCLUSIONS: ACL elasticity, FFK, and KFEH was affected not only by E2 but also tissue temperature. However, E2 had more impact on ACL elasticity while tissue temperature had more impact on FFK and KFEH at 38 °C warming.

Moist heat or dry heat for delayed onset muscle soreness.

BACKGROUND: Heat is commonly used in physical therapy following exercise induced delayed onset muscle soreness (DOMS). Most heat modalities used in a clinical setting for DOMS are only applied for 5 to 20 minutes. This minimal heat exposure causes little, if any, change in deep tissue temperature. For this reason, long duration dry chemical heat packs are used at home to slowly and safely warm tissue and reduce potential heat damage while reducing pain associated from DOMS. Clinically, it has been shown that moist heat penetrates deep tissue faster than dry heat. Therefore, in home use chemical moist heat may be more efficacious than dry heat to provide pain relief and reduce tissue damage following exercise DOMS. However, chemical moist heat only lasts for 2 hours compared to the 8 hours duration of chemical dry heat packs. The purpose of this study was to compare the beneficial effect of dry heat versus moist heat on 100 young subjects after exercise induce DOMS. METHODS: One hundred subjects exercised for 15 minutes accomplishing squats. Before and for 3 days after, strength, muscle soreness, tissue resistance, and the force to passively move the knee were recorded. Heat and moist heat were applied in different groups either immediately after exercise or 24 hours later. RESULTS: The research results of this study showed that immediate application of heat, either dry (8 hours application) or moist (2 hours application), had a similar preservation of quadriceps muscle strength and muscle activity. Results also revealed that the greatest pain reduction was shown after immediate application of moist heat. Never the less, immediate application of dry heat had a similar effect but to a lesser extent. CONCLUSION: It should be noted that moist heat had not only similar benefits of dry heat but in some cases enhanced benefits, and with only 25% of the time of application of the dry heat.

The effect of acute administration of vitamin D on micro vascular endothelial function in Caucasians and South Asian Indians.

BACKGROUND: Vitamin D is a modulator of the immune system. There is some limited evidence that it also increases local blood flow in response to stress. MATERIAL AND METHODS: In the present study, we examined 20 age matched subjects; 10 whom were from India and 10 Caucasians from the United States. Subjects were administered 4000 IU of Vitamin D3 for 3 weeks at breakfast. The function of the endothelial cells was evaluated in 2 ways; first, the response to 4 minutes of vascular occlusion was measured with a laser Doppler flow meter and second, the blood flow response to local heat at 42°C for 6 minutes. RESULTS: The results of the experiments showed that, as reported previously, the endothelial function in people from India was less than their Caucasian counterparts. The blood flow response to heat was reduced after 3 weeks administration of vitamin D in both groups and the response to vascular occlusion in the Caucasian group. But there was only a 20% reduction in the blood flow response to heat in the Caucasian group and a 50% reduction in the group from India. CONCLUSIONS: Thus acute doses of vitamin D may increase vascular tone and reduce blood flow to tissue during stressors. Dosages administered for a longer duration may have beneficial effects on endothelial function but this was not examined here.

What is more damaging to vascular endothelial function: Diabetes, age, high BMI, or all of the above?

BACKGROUND: It is well established that there is a reduction in the skin blood flow (SBF) in response to heat with age and diabetes. While it is known that high BMI creates a stress on the cardiovascular system and increases the risk of all cause of morbidity and mortality, little is known of the effect of high BMI on SBF response to heat. Since diabetes is associated with age and a higher BMI, the interrelationship between age, BMI and SBF needs to be investigated to better understand the contribution diabetes alone has to endothelial impairment. MATERIAL AND METHODS: This study examined the SBF to heat in young and old people with low and high BMI and people with diabetes with high BMI to determine the contribution these variables have on SBF. Subjects were ten young and older people with BMI <20 and ten young and older people with BMI >20 and ten subjects with diabetes with BMI >20. The SBF response, above the quadriceps, was determined during a 6 minutes exposure to heat at 44°C. RESULTS: Even in young people, SBF after the stress of heat exposure was reduced in subjects with a high BMI. The effect of BMI was greatest in young people and lowest in older people and people with diabetes; in people with diabetes, BMI was a more significant variable than diabetes in causing impairment of blood flow to heat. BMI, for example, was responsible for 49% of the reduction in blood flow after stress heat exposure (R=-0.7) while ageing only accounted for 16% of the blood flow reduction (R=-0.397). CONCLUSIONS: These results would suggest the importance of keeping BMI low not only in people with diabetes to minimize further circulatory vascular damage, but also in young people to diminish long term circulatory vascular compromise.

Electroencephalography to assess motor control during balance tasks in people with diabetes.

BACKGROUND: Balance is sensed through peripheral and central receptors and mediated by central control through the brain and spinal cord. Although some evidence exists as to the areas of the brain involved and how processing of data occurs in young individuals, nothing has been published on people with diabetes. The purpose of this study was to examine the electroencephalogram (EEG) during common sensorimotor and balance training tasks and to relate these to task difficulty. SUBJECTS AND METHODS: Postural sway and EEG change of alpha, beta, and sigma wave bands were measured in 17 young subjects, 10 older subjects, and 10 subjects with diabetes during eight progressively more difficult balance tasks with eyes open and closed, feet in tandem or apart, and on foam or a firm surface. RESULTS: EEG power of beta and sigma wave bands showed significant increases on the cortical and parietal areas of the brain relative to the control tasks when eyes were open (P<0.05). The cortical involvement decreased as the task became more difficult with vision and somatosensory information reduced, whereas that of the parietal area increased with task difficulty. The greatest increase was in subjects with diabetes, and the least was in younger people. Individuals with diabetes had increased sigma and beta EEG power in all regions of the brain examined with increased complexity of the balance task. CONCLUSIONS: This study demonstrated cortical and parietal involvement in static balance tasks commonly used in sensorimotor training. The results support the proposal that there was increased subcortical control with increase in task difficulty in the young subjects, but in subjects with diabetes, there was a major increase in activity across the brain.