Changes In Muscle Thickness Research Articles

CMS-NET: deep learning algorithm to segment and quantify the ciliary muscle in swept-source optical coherence tomography images.

The ciliary muscle plays a role in changing the shape of the crystalline lens to maintain the clear retinal image during near work. Studying the dynamic changes of the ciliary muscle during accommodation is necessary for understanding the mechanism of presbyopia. Optical coherence tomography (OCT) has been frequently used to image the ciliary muscle and its changes during accommodation in vivo. However, the segmentation process is cumbersome and time-consuming due to the large image data sets and the impact of low imaging quality. This study aimed to establish a fully automatic method for segmenting and quantifying the ciliary muscle on the basis of optical coherence tomography (OCT) images. A perspective cross-sectional study. In this study, 3500 signed images were used to develop a deep learning system. A novel deep learning algorithm was created from the widely used U-net and a full-resolution residual network to realize automatic segmentation and quantification of the ciliary muscle. Finally, the algorithm-predicted results and manual annotation were compared. For segmentation performed by the system, the total mean pixel value difference (PVD) was 1.12, and the Dice coefficient, intersection over union (IoU), and sensitivity values were 93.8%, 88.7%, and 93.9%, respectively. The performance of the system was comparable with that of experienced specialists. The system could also successfully segment ciliary muscle images and quantify ciliary muscle thickness changes during accommodation. We developed an automatic segmentation framework for the ciliary muscle that can be used to analyze the morphological parameters of the ciliary muscle and its dynamic changes during accommodation.

Does wing use and disuse cause behavioural and musculoskeletal changes in domestic fowl (Gallus gallus domesticus)?

Domestic chickens may live in environments which restrict wing muscle usage. Notably, reduced wing activity and accompanying muscle weakness are hypothesized risk factors for keel bone fractures and deviations. We used radio-frequency identification (RFID) to measure duration spent at elevated resources (feeders, nest-boxes), ultrasonography to measure muscle thickness (breast and lower leg) changes, radiography and palpation to determine fractures and deviations, respectively, following no, partial (one-sided wing sling) and full (cage) immobilization in white- and brown-feathered birds. We hypothesized partially immobilized hens would reduce elevated resource usage and that both immobilization groups would show decreased pectoralis thickness (disuse) and increased prevalence of fractures and deviations. Elevated nest-box usage was 42% lower following five weeks of partial immobilization for brown-feathered hens but no change in resource usage in white-feathered birds was observed. Fully immobilized, white-feathered hens showed a 17% reduction in pectoralis thickness, while the brown-feathered counterparts showed no change. Lastly, fractures and deviations were not affected in either strain or form of wing immobilization; however, overall low numbers of birds presented with these issues. Altogether, this study shows a profound difference between white- and brown-feathered hens in response to wing immobilization and associated muscle physiology.

Changes in pectoralis major stiffness and thickness following radiotherapy for breast cancer: A 12-month follow-up case series

Radiotherapy (RT) is a common and often essential treatment for breast cancer, but has been associated with pectoralis major (PM) muscle fibrosis and atrophy. In an initial prospective evaluation, we assessed muscle stiffness and muscle thickness of the sternocostal and clavicular regions of the PM with ultrasound shear wave elastography and B-mode imaging. Changes in PM muscle stiffness and thickness following RT can be detected within the first twelve months of RT completion. These parameters may potentially be useful for screening of patients who would benefit from post-RT physical therapy. Further studies with larger sample sizes that include patients who receive nodal radiation are necessary to confirm these findings.

Adding High-Intensity Interval Training to Classical Resistance Training Does Not Impede the Recovery from Inactivity-Induced Leg Muscle Weakness.

Inactivity is known to induce muscle weakness, and chronically increased levels of reactive oxygen species (ROS) are proposed to have a central causative role in this process. Intriguingly, high-intensity interval training (HIIT), which involves bursts of high ROS production, can have positive effects in pathological conditions with chronically increased ROS. Here, young male volunteers were exposed to 3 weeks of unloading of the dominant leg followed by 3 weeks of resistance training without (Ctrl group) or with the addition of all-out cycling HIIT. Changes in muscle thickness were assessed by ultrasonography, and contractile function was studied by measuring the torque during maximal voluntary contractions (MVC). The results show an ~6% decrease in vastus lateralis thickness after the unloading period, which was fully restored after the subsequent training period in both the Ctrl and HIIT groups. MVC torque was decreased by ~11% after the unloading period and recovered fully during the subsequent training period in both groups. All-out cycling performance was improved by the 3 weeks of HIIT. In conclusion, the decline in muscle size and function after 3 weeks of unloading was restored by 3 weeks of resistance training regardless of whether it was combined with HIIT.

623: ASSESSING CLINICAL VARIABLES ASSOCIATED WITH FEMORAL MUSCLE DECAY IN CRITICALLY ILL CHILDREN

Introduction: Skeletal muscle wasting is a well-described entity of critical illness and has been found to be associated with prolonged ICU and hospital stays and acquired morbidities. Recent studies have shown ultrasound measurements of the quadriceps femoris muscle are a reliable method to track muscle decay in the pediatric population. Our study aims to identify significant clinical variables that are associated with muscle decay in critically ill mechanically ventilated children. Methods: A prospective, single center analysis was performed on sixty-seven sedated and mechanically ventilated patients admitted to the pediatric ICU between February 2021-March 2022. Point of care ultrasound was used to measure the thickness of the quadriceps femoris muscle serially for up to the first 7 days of study enrollment. Average daily change in muscle thickness was calculated for each subject. Clinical variables measured included nutritional adequacy, fluid overload, sedative and paralytic use, steroid exposure, early mobilization, disease severity, mortality, and ICU and hospital length of stay (LOS). Results: Change in muscle thickness in our patient population was similar to prior studies with a mean daily change of -1.9% [IQR -0.8, -5.0]. Patients with adequate cumulative caloric intake, as defined by >60% of goal, were shown to have less muscle decay compared to those with inadequate caloric intake (-1.8% vs. -2.4%, p< 0.001). Average daily change in muscle thickness was found to correlate with both ICU and hospital LOS (r = 0.328, p = 0.007 and r = 0.393, p = 0.001). No correlation was found between daily change in muscle thickness and mortality, disease severity, and fluid balance. Similarly, early mobilization, sedative and paralytic use, and steroid exposure did not show significant associations with change in muscle thickness. Conclusions: We demonstrate quadriceps femoris muscle decay in critically ill children as measured by ultrasonography. Average daily muscle decay was associated with longer ICU and hospital length of stay. Children with adequate cumulative caloric intake were found to have less muscle decay than those with inadequate caloric intake.

Rectus abdominis muscle thickness change and activation increase during planks performed on different surfaces.

The plank is a common exercise used to evaluate core function. Surface electromyography (sEMG) and ultrasound can be used simultaneously to measure muscle activity. We aimed to compare the %-thickness and %-activation during the plank performed on three surfaces and to determine agreement and relationship between rectus abdominis (RA) %-thickness of a rested tabletop position and %-activation normalized to quiet tabletop position during the plank on three surfaces. In this cross-sectional study, ultrasound and sEMG measured RA muscle function during the first 5-s and last 5-s of a plank performed on a table, yoga mat, and fitness ball. A repeated measures ANOVA compared differences in %-thickness change and Friedman's tests compared differences in %-activation, alpha set a priori p ≤ 0.05. Bland-Altman plots measured agreement between instruments. Spearman's rho determined relationships between instruments. There was no difference between %-thickness change across surfaces during the first 5-s or last 5-s, or between %-activation during the last 5-s. The %-activation of the RA during the first 5-s performed on the fitness ball was higher than the table and yoga mat (p < 0.001). Ultrasound and sEMG had weak relationships across all surfaces (ρ = - 0.078 to 0.116). The first 5-s of the plank performed on the fitness ball requires a greater RA activation. Ultrasound could not detect changes in %-thickness of the RA during the plank which may be influenced by the type of contraction. Comparison between these measurement tools during isometric exercise should be used with caution.

Musculoskeletal Ultrasound Shows Muscle Mass Changes during Post-Acute Care Hospitalization in Older Men: A Prospective Cohort Study.

This study aimed to prospectively assess changes in muscle thickness (MT) and the cross-sectional area (CSA) of the rectus femoris (RF) muscle in a cohort of older adults, using musculoskeletal ultrasound at admission and at a 2-week follow-up during hospitalization in a post-acute care unit. Differences in frailty status and correlations of MT-RF and CSA-RF with current sarcopenia diagnostic criteria were also studied. Forty adults aged 79.5 (SD 9.5) years (57.5% women) participated, including 14 with frailty and 26 with pre-frailty. In the first week follow-up, men had a significant increase in MT (0.9 mm [95%CI 0.3 to 1.4], p = 0.003) and CSA (0.4 cm2 [95%CI 0.1 to 0.6], p = 0.007). During the second week, men continued to have a significant increase in MT (0.7 mm [95%CI 0.0 to 1.4], p = 0.036) and CSA (0.6 cm2 [95%CI 0.01 to 1.2], p = 0.048). Patients with frailty had lower values of MT-RF and CSA-RF at admission and during the hospitalization period. A moderate-to-good correlation of MT-RF and CSA with handgrip strength, fat-free mass and gait speed was observed. Musculoskeletal ultrasound was able to detect MT-RF and CSA-RF changes in older adults admitted to a post-acute care unit.

The Effects of Offset Loading Versus Traditional Loading in the Bench Press Exercise on Muscle Thickness and Strength in Trained Males

PurposeThis study compared the effects of offset loading (OSL) versus traditional loading (TDL) in the bench press exercise on pectoral muscle thickness and bench press strength over a 4-week mesocycle. Methods: Twenty male participants aged 18–45 years with at least 5 years of bench press experience and a bench press one-repetition maximum equal to or greater than their body mass were randomly assigned to OSL and TDL groups. Before and after the 4-week mesocycle, pectoral muscle thickness was assessed via ultrasonography and muscle strength was assessed by bench press one-repetition maximum. Effects were explored with two-way mixed ANOVA and non-clinical magnitude-based inferences. Results: No group-by-time interaction was detected for any variable (P > 0.05). When compared to small magnitudes, the pectoralis major muscle thickness changes were likely greater in OSL compared to TDL for the dominant (ES = 0.70; 87% likely greater) and nondominant pectoralis (ES = 0.77; 91% likely greater) as well as the sum of both pectorals (ES = 0.80; 92% likely greater). Similarly, a likely greater effect for absolute (ES = 0.57; 82% likely) and relative (ES = 0.67; 85% likely) bench press strength was seen with OSL. Conclusion: Magnitude-based inferences interpreted here support the notion that OSL may be an advantageous training modality to enhance pectoral muscle thickness and bench press strength.

Association Between Knee Extension Strength and Functional Capacity After Intensive Care Unit Discharge: A 6-Mo Prospective Cohort Study.

Assessing functional improvement after intensive care unit discharge is particularly challenging. The aim of this study was to measure the association between (1) changes in knee extension muscle strength or quadriceps femoris and rectus femoris muscle thickness and (2) changes in functionality/function-related measurements in post-intensive care unit patients. This prospective cohort study included adult patients without previous disability, consecutively selected after intensive care unit discharge. Some parameters, such as Short-Form 36, 6-min walking test, 1-min sit-to-stand, and Short Physical Performance Battery, were measured at baseline and 3 and 6 mos after discharge. Correlations were assessed and regression models were built to assess the association between evolution in knee extension strength or muscle thickness and evolution in functional tests. Thirty patients completed the follow-up. Moderate correlation was found between knee extension strength change and Short-Form 36 physical functioning (correlation coefficient [ ρ ] = 0.53), 6-min walking test ( ρ = 0.38), 1-min sit-to-stand ( ρ = 0.52), and Short Physical Performance Battery ( ρ = 0.38). Baseline values and changes in knee extension strength moderately predicted evolution in Short-Form 36 physical functioning ( r2 = 0.32, P = 0.006). Changes in muscle thickness were overall not associated with changes in functional variables. Changes in knee extension muscle strength may inform on functional progression over time after intensive care unit discharge, although confirmatory studies are needed.

Morphometry of thenar muscles by water bath ultrasonography in trapeziometacarpal osteoarthritis: intra- and inter-rater reliability.

We studied the intra- and inter-rater reliability of muscle thickness and cross-sectional area measurements of thenar muscles with a water bath ultrasonography technique in eight healthy volunteers and 16 patients with trapeziometacarpal osteoarthritis. Thickness and cross-sectional area of the opponens pollicis, abductor pollicis brevis, flexor pollicis brevis, first dorsal interosseous and adductor pollicis muscle were measured. The results showed changes in the morphometric properties of the thenar muscles in patients with trapeziometacarpal osteoarthritis (TMC OA) compared with the healthy volunteers. In the dominant-sided patients (n = 14), there were lower cross-sectional area values for the abductor pollicis brevis and opponens pollicis muscles. In the non-dominant-sided patients (n = 10), there were lower cross-sectional area values for the abductor pollicis brevis and flexor pollicis brevis and lower muscle thickness of the abductor pollicis brevis. The water bath ultrasonography technique could be used to diagnose and treat diseases where changes in thenar muscle thickness and cross-sectional area can be expected.Level of evidence: III.

Ultrasonographic changes in quadriceps femoris thickness in women with normal pregnancy and women on bed rest for threatened preterm labor

This study aimed to evaluate the changes in quadriceps femoris muscle thickness during the pregnancy and postpartum periods and to elucidate the effect of bed rest for threatened preterm labor on muscle thickness. In 26 women with normal pregnancy, quadriceps femoris thickness was measured at 11–13, 26, 30, and 35 weeks’ gestation, and at 3–5 days and 1 month postpartum using ultrasonography. In 15 pregnant women treated with bed rest for threatened premature labor, quadriceps femoris thickness was measured at 30 and 35 weeks’ gestation and postpartum. In women with normal pregnancy, quadriceps femoris thickness increased, peaking at 35 weeks’ gestation, followed by a postpartum decrease. In women on bed rest, quadriceps femoris thickness showed no significant change during the pregnancy and postpartum periods, and the muscle was significantly thinner at 35 weeks’ gestation than that in women with normal pregnancy. In conclusion, a significant increase in quadriceps femoris muscle thickness during normal pregnancy was found using ultrasonography. Meanwhile, in pregnant women on bed rest treatment, the quadriceps femoris was significantly thinner in the late third trimester than that in normal pregnant women. Prolonged bed rest can affect normal changes in the quadriceps femoris muscle thickness during the pregnancy and postpartum periods.

Investigating the rate of skeletal muscle atrophy in men and women in the intensive care unit: a prospective observational study

Muscle atrophy greatly affects the prognosis of patients in the intensive care unit, but the rate of change remains unclear. In this prospective observational study, we used ultrasound to measure the change in muscle thickness of the rectus femoris (RF) and vastus intermedius (VI) in 284 patients who were admitted to the SICU of Taoyuan General Hospital between January 1 and June 30, 2020. Patients were excluded if there is a wound at the right thigh which hinders the ultrasonography probe from placing. Daily rates of muscle atrophy were calculated using linear analysis and the ratios of change were plotted against the period of hospitalization. Patient characteristics were adjusted using propensity score matching and differences between men and women were analyzed. A linear mixed model was used to calculate the influence of other factors on muscle loss. The average daily atrophy rates of the RF and VI were 0.84% and 0.98%, respectively. The rate of atrophy was the highest in the third and fourth weeks. Daily atrophy rates of the RF and VI were approximately three times higher in women than in men. Protective factors of muscle atrophy included higher BMI and lower initial thickness of the RF and VI. Our study depicts the trend of muscle atrophy in the ICU and suggests more discussion in prevention to be conducted especially for women.

Skeletal Muscle Changes in the First Three Months of Stroke Recovery: A Systematic Review.

BackgroundRehabilitation is important in the first months after a stroke for recovery of functional ability, but it is also challenging, since distinct recovery trajectories are seen. Therefore, studying the early changes in muscle characteristics over time (e.g. muscle strength, muscle mass and muscle volume), which are known to be associated with functional abilities, may deepen our understanding of underlying recovery mechanisms of stroke survivors.ObjectiveThis systematic review aims to describe the longitudinal changes in skeletal muscles, including muscle strength, muscle mass and muscle volume, during the first 3 months post-stroke.MethodsElectronic searches were conducted in Medline, Scopus and CENTRAL. Longitudinal cohort studies or controlled interventional trials that report data about patients in the first 3 months after stroke were identified. Skeletal muscle characteristics should be measured at least twice within 3 months post-stroke by objective, quantitative assessment methods (e.g. dynamometry, ultrasound, computed tomography). Effect sizes were calculated as Hedges’ g using standardized mean differences.ResultsA total of 38 studies (1,097 subjects) were found eligible. Results revealed an mean increase on the paretic side for upper and lower limb muscle strength (small to moderate effect sizes), whereas muscle thickness decreased (moderate to large effect sizes). Similar, but smaller, effects were found on the non-paretic side. There were insufficient data available to draw conclusions about lean muscle mass and muscle cross-sectional area. No studies aimed at investigating distinct trajectories of the muscle changes.ConclusionMuscle strength and thickness changes during the first 3 months after stroke in both the paretic and non-paretic side. Future studies should aim to understand “how” the stroke-induced muscle strength changes are achieved. Exploring existing data from longitudinal studies, by using cluster analyses, such as pattern recognition, could add to the current knowledge-base.LAY ABSTRACTAfter a stroke, it is important to restore functional ability as much as possible. Studying changes in the muscles (e.g. muscle strength, muscle thickness, muscle volume) during the first months post-stroke can help to elucidate individual variations and the underlying repair mechanisms. A systematic search of the literature was performed for studies of objective quantifiable measurements of muscles at least 2 times during the first 3 months after stroke. A total of 38 studies (with in total 1,097 patients) met these criteria. Overall, an improvement in strength was measured on the paretic side for both the upper and lower limbs, but muscle thickness decreased. Similar, but smaller, effects were found on the non-paretic side. For other muscle parameters insufficient data were found to draw conclusions. Because understanding the underlying mechanism of muscle changes post-stroke can improve rehabilitation programmes, further studies should focus on why these muscle strength changes occur.

Lumbar multifidus thickness changes during active leg raising with ultrasound imaging can detect patients with chronic non-specific low back pain

BackgroundAltered lumbar multifidus (LM) activation has been found in populations with non-specific chronic low back pain (NSCLBP). Objective: To detect differences in LM muscle thickness at rest and during active manoeuvres between patients with NSCLBP and pain-free controls and to analyze the ability of LM thickness change during the active straight leg raise (ASLR) with rehabilitative ultrasound imaging to detect patients with NSCLBP. DesignCross-sectional observational study. MethodsSeventy volunteers (50% patients NSCLBP) were recruited. 18 B-mode images of LM at L4-L5 or L5-S1 level selecting the most symptomatic level (both sides, six at rest and three during ASLR) were collected by a blinded assessor. Differences between patients and controls in LM muscle thickness at rest, during ASLR (holding 3sec), and 5 s after ASLR were calculated. In addition, discriminant validity was evaluated by calculating the area under the receiver operating characteristic curve (ROC), sensitivity, specificity and positive and negative likelihood ratio. ResultsSignificant LM thickness change differences during ASLR were found within and between groups: bilaterally, LM thickness change during ASLR was significantly higher in healthy controls than in NSCLBP patients. Ipsilateral LM muscle thickness change was sensitive to detect individuals with NSCLBP (ROC = 0.79–0.80). ConclusionPain-free individuals exhibited significantly greater LM thickness changes bilaterally during the ASLR compared to patients with NSCLBP. LM thickness change during the ASLR has good validity for discriminating patients with NSCLBP. Further studies should assess benefits of LM training programs in the management of these patients.

Increase in muscle mass of the quadriceps is related to decrease in intramuscular adipose tissue in convalescent stroke patients: A longitudinal study.

A previous study indicated that an increase in muscle mass is related to a decrease in intramuscular adipose tissue in older peoples. However, the longitudinal relationship between muscle mass and intramuscular adipose tissue of stroke patients remains unclear. This study aimed to examine the longitudinal relationships between muscle mass and intramuscular adipose tissue of the quadriceps on the paretic and non-paretic sides in convalescent stroke patients. This longitudinal study included 24 convalescent stroke patients. Ultrasound images were acquired at hospital admission and discharge using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were evaluated with muscle thickness and echo intensity, respectively. Multiple regression analysis was performed to confirm whether changes in echo intensity of the quadriceps on the paretic and non-paretic sides were related to changes in muscle thickness of those. The age, sex, days from onset stroke, change in the subcutaneous fat thickness, and paretic lower extremity function were set as an independent variable. Change in echo intensity of the quadriceps on the paretic side (β=- 0.55, p=0.018) was independently and significantly associated with changes in muscle thickness of the quadriceps on the paretic side. Similarly, change in echo intensity of the quadriceps on the non-paretic side (β=-0.55, p=0.013) was independently and significantly associated with change in muscle thickness of the quadriceps on the non-paretic side. Our findings indicate that muscle mass and intramuscular adipose tissue of the quadriceps are strongly and negatively correlated and an increase in muscle mass of the quadriceps is related to a decrease in intramuscular adipose tissue on the paretic and non-paretic sides in convalescent stroke patients. Furthermore, we must recognize that convalescent stroke patients with a decrease in muscle mass have an increase in intramuscular adipose tissue.

Changes In Muscle Thickness, Strength, And Soreness Following Resistance Training With Direct Pulsed Current

Changes In Muscle Thickness, Strength, And Soreness Following Resistance Training With Direct Pulsed Current

Effect Of Proximity To Failure During Resistance Training On Vastus Lateralis Muscle Thickness

PURPOSE: To compare changes in muscle thickness at two sites (50% and 70%) of the vastus lateralis (VL50 MT, VL70 MT) between training programs with different proximities to failure using the repetitions in reserve (RIR)-based rating of perceived exertion (RPE) scale. METHODS: Fourteen males (height: 175.77 ± 5.72 cm, body mass: 80.15 ± 13.12 kg, squat one-repetition maximum-1RM relative to body mass: 1.72 ± 0.25) with ≥2 yrs of back squat experience were assigned to either 4-6 RPE, n = 7 (4-6 RIR) or 7-9 RPE, n = 7 (1-3 RIR) for 8wks. Ultrasonography was performed 48 hours before the first training session and 48 hours after the last session. Both groups performed the back squat 3x/wk on non-consecutive days (e.g., Mon., Wed., Fri.) using an undulating resistance training program, which decreased repetitions throughout. Weeks 1-3 consisted of 10, 8, and 6 repetitions on sessions 1, 2, and 3, respectively; weeks 4-5 consisted of 9, 7, and 5 repetitions; and weeks 6-7 consisted of 8, 6, and 4 repetitions. Week 1 was an introductory week in which fewer sets were performed at a lower RPE. Week 8 was a taper with 4 and 2 repetition days on session 1 and session 2, respectively, followed by post-testing in session 3. In weeks 2-7 (i.e., main training period), 10 weekly sets were performed for both the squat and bench press. Subjects were instructed to select a load in which the set ended with 4-6 RPE or 7-9 RPE. Equivalence testing and 90% confidence intervals were used to compare changes in VL50 MT and VL70 MT. Independent t-tests compared average intensity (% of 1RM) and total relative volume (% of 1RM × reps) performed. RESULTS: Equivalence testing confidence intervals crossed both g = 0.0 and g = ±0.20 thresholds; suggesting changes in VL50 MT and VL70 MT did not statistically differ between groups but were also inconclusive (VL50: 22.77 ± 4.77 to 21.74 ± 4.17 mm; -3.50% vs. 22.10 ± 4.25 to 20.73 ± 4.49 mm; -6.33%; VL70: 18.47 ± 6.59 to 19.93 ± 7.1 mm; +9.43% vs. 16.91 ± 6.67 to 17.04 ± 5.2 mm; +3.47%). The 7-9 RPE group trained with significantly higher intensity (82.2 ± 5.18 vs. 72.0 ± 4.57% of 1RM, p = 0.002) and performed more relative volume (338.7 ± 21.46 vs. 380.1 ± 25.83 kg, p = 0.007). CONCLUSIONS: Our findings do not conclusively indicate whether vastus lateralis MT changes were statistically similar or statistically different between groups.

Effect Of Proximity To Failure During Resistance Training On Pectoralis Major Muscle Thickness

PURPOSE: To compare changes in pectoralis major muscle thickness (chest MT) between training programs with different proximities to failure using the repetitions in reserve (RIR)-based rating of perceived exertion (RPE) scale. METHODS: Fourteen males (height: 175.77 ± 5.72 cm, body mass: 80.15 ± 13.12 kg, bench press one-repetition maximum-1RM relative to body mass: 1.27 ± 0.12) with ≥2 yrs of bench press experience were assigned to one of two groups: 1) 4-6 RPE, n = 7 (4-6 RIR) or 2) 7-9 RPE, n = 7 (1-3 RIR) for 8wks. Pre and post chest MT via ultrasound was performed 48 hours before the first training session and 48 hours after the last training session, respectively. Both groups performed the bench press 3x/wk on non-consecutive days (e.g., Mon., Wed., Fri.) using the same number of sets and repetitions on an undulating resistance training program, which linearly decreased repetitions throughout. Weeks 1-3 consisted of 10, 8, and 6 repetitions on sessions 1, 2, and 3, respectively; weeks 4-5 consisted of 9, 7, and 5 repetitions; and weeks 6-7 consisted of 8, 6, and 4 repetitions. Week 1 served as an introductory week in which fewer sets were performed at a lower RPE. Week 8 served as a taper with 4 and 2 repetition days on session 1 and session 2, respectively, followed by post-testing in session 3. In weeks 2-7 (i.e., main training period), 10 weekly sets were performed. Subjects were instructed to select a load in which the set ended with 4-6 RPE or 7-9 RPE. Equivalence testing and 90% confidence intervals were used to compare changes in chest MT. Independent t-tests were used to compare relative intensity (% of 1RM) and relative volume (% of 1RM × reps). RESULTS: Equivalence testing confidence intervals crossed both g = 0.0 and g = ±0.20 thresholds; suggesting changes in chest MT did not statistically differ between 4-6 RPE and 7-9 RPE groups but were also inconclusive (24.21 ± 5.75 to 25.00 ± 5.51 mm; +7.89% vs. 22.50 ± 6.46 to 22.73 ± 4.30 mm; +4.05%). No significant differences were observed between the 4-6 RPE and 7-9 RPE groups for relative intensity (80.1 ± 4.23 vs. 83.9 ± 3.15% of 1RM; p = 0.083) or relative volume (377.0 ± 18.24 vs. 393.5 ± 15.34 kg; p = 0.093). CONCLUSIONS: Our findings do not conclusively indicate whether chest MT changes were statistically similar or statistically different between resistance training with 4-6 RPE and 7-9 RPE.

Loaded inter-set stretch may selectively enhance muscular adaptations of the plantar flexors.

The purpose of this study was to evaluate differences in changes in muscle strength and muscle thickness (MT) of the plantar flexor muscles between traditional resistance training (RT) involving passive rest and RT combined with inter-set stretch in the calf raise exercise. Employing a within-subject design, 21 young, healthy men performed plantar flexion exercises twice per week in both a traditional RT (TRAD) format and combined with a 20-second inter-set stretch (STRETCH). One leg was randomly assigned to the TRAD condition and the contralateral leg performed the STRETCH condition throughout the 8-week study period. Dependent variables included MT of the lateral gastrocnemius (LG), medial gastrocnemius (MG) and the soleus (SOL), and isometric strength of the plantar flexors. Results indicated a potential beneficial hypertrophic effect of STRETCH compared to TRAD for the SOL [0.7 mm, CI90% = (0, 1.6)], while the LG had more ambiguous effects [0.4 mm (-0.4, 1.3)] and MG effects were equivocal [0 mm (-0.6, 0.7)]. In general, LG demonstrated greater standardized growth [z = 1.1 (1, 1.3)] as compared to MG [z = 0.3 (0.2, 0.5)] and SOL [z = 0.3 (0.2, 0.5)]. Measures of isometric strength showed a modest advantage to STRETCH. In conclusion, loaded inter-set stretch may enhance MT of the soleus but effects on the gastrocnemii appear uncertain or unlikely in untrained men; plantar flexor strength appears to be modestly enhanced by the interventional strategy.

Providing Visual Biofeedback Using Brightness Mode Ultrasound During a Golf Swing.

Using ultrasound biofeedback in conjunction with verbal cueing can increase muscle thickness more than verbal cueing alone and may augment traditional rehabilitation techniques in an athletic, physically active population. Brightness mode (B-mode) ultrasound can be applied using frame-by-frame analysis synchronized with video to understand muscle thickness changes during these dynamic tasks. Visual biofeedback with ultrasound has been established in static positions for the muscles of the lateral abdominal wall. However, by securing the transducer to the abdomen using an elastic belt and foam block, biofeedback can be applied during more specific tasks prevalent in lifetime sports, such as golf. To analyze muscle activity during a golf swing, muscle thickness changes can be compared. The thickness must increase throughout the task, indicating that the muscle is more active. This methodology allows clinicians to immediately replay ultrasound videos for patients as a visual tool to instruct proper activity of the muscles of interest. For example, ultrasound can be used to target the external and internal obliques, which play an important role in swinging a golf club or any other rotational sport or activity. This methodology aims to increase oblique muscle thickness during the golf swing. Additionally, the timing of muscle contraction can be targeted by instructing the patient to contract the abdominal muscles at specific time points, such as the beginning of the downswing, with the goal of improving muscle firing patterns during tasks.