Contralateral effects of unilateral training: sparing of muscle strength and size after immobilization

2018 ◽  
Vol 43 (11) ◽  
pp. 1131-1139 ◽  
Author(s):  
Justin W. Andrushko ◽  
Layla A. Gould ◽  
Jonathan P. Farthing

The contralateral effects of unilateral strength training, known as cross-education of strength, date back well over a century. In the last decade, a limited number of studies have emerged demonstrating the preservation or “sparing” effects of cross-education during immobilization. Recently published evidence reveals that the sparing effects of cross-education show muscle site specificity and involve preservation of muscle cross-sectional area. The new research also demonstrates utility of training with eccentric contractions as a potent stimulus to preserve immobilized limb strength across multiple modes of contraction. The cumulative data in nonclinical settings suggest that cross-education can completely abolish expected declines in strength and muscle size in the range of ∼13% and ∼4%, respectively, after 3–4 weeks of immobilization of a healthy arm. The evidence hints towards the possibility that unique mechanisms may be involved in preservation effects of cross-education, as compared with those that lead to functional improvements under normal conditions. Cross-education effects after strength training appear to be larger in clinical settings, but there is still only 1 randomized clinical trial demonstrating the potential utility of cross-education in addition to standard treatment. More work is necessary in both controlled and clinical settings to understand the potential interaction of neural and muscle adaptations involved in the observed sparing effects, but there is growing evidence to advocate for the clinical utility of cross-education.

Biomechanics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 145-151
Author(s):  
David Alan Phillips ◽  
Angelic Rose Del Vecchio ◽  
Kevin Carroll ◽  
Evan Lee Matthews

Electromyography (EMG) is a research tool used in gait analysis, muscle coordination evaluation, clinical evaluation and sports techniques. Electromyography can provide an insight into neural adaptations, cross education effects, bilateral contraction deficiencies, and antagonist activity in exercise-related movements. While there are clear benefits to using EMG in exercise-related professions, accessibility, cost, and difficulty interpreting the data limit its use in strength and clinical settings. We propose a practical EMG assessment using the isometric squat to identify compensatory activation patterns and report early observations. Ten healthy participants were recruited. Participants performed a 2-min isometric handgrip protocol and an isometric squat protocol. The isometric handgrip was used to identify the expected EMG amplitude response solely due to fatigue. There was a significant increase in EMG amplitude after 2 min (p < 0.05), with the relative increase of 95% CI (1.4%; 27.4%). This indicates the relative increase in EMG amplitude expected if the only influence was fatigue in the 2-min protocol. In the isometric squat protocol, we identified a number of different muscle activation compensation strategies with relative EMG amplitude increases outside of this bandwidth. One subject demonstrated a quadricep compensation strategy with a 188% increase in activation, while reducing activation in both the hamstrings and lower back by 12%. Exercise professionals can use this information to design exercise programs specifically targeting the unloaded muscles during the isometric squat.


Author(s):  
Elisa Benito-Martínez ◽  
Diego Senovilla-Herguedas ◽  
Julio César de la Torre-Montero ◽  
María Jesús Martínez-Beltrán ◽  
María Mercedes Reguera-García ◽  
...  

Neuromuscular electrostimulation (NMES) has been used mainly as a method to promote muscle strength, but its effects on improving blood flow are less well known. The aim of this study is to deepen the knowledge about the local and contralateral effects of the application of symmetric biphasic square currents on skin temperature (Tsk). An experimental pilot study was developed with a single study group consisting of 45 healthy subjects. Thermographic evaluations were recorded following the application of NMES to the anterior region of the thigh. The results showed an increase in the maximal Tsk of 0.67% in the anterior region of the thigh where the NMES was applied (p < 0.001) and an increase of 0.54% (p < 0.01) due to cross-education effects, which was higher when the NMES was applied on the dominant side (0.79%; p < 0.01). The duration of the effect was 20 min in the dominant leg and 10 min in the nondominant one. The application of a symmetrical biphasic current (8 Hz and 400 μs) creates an increase in the maximal Tsk at the local level. A temperature cross-education effect is produced, which is greater when the NMES is applied on the dominant side. This could be a useful noninvasive measurement tool in NMES treatments.


2017 ◽  
Vol 52 (7) ◽  
pp. 649-655 ◽  
Author(s):  
Julie A. Hides ◽  
Jazmin C. Walsh ◽  
Melinda M. Franettovich Smith ◽  
M. Dilani Mendis

Context: Low back pain (LBP) and lower limb injuries are common among Australian Football League (AFL) players. Smaller size of 1 key trunk muscle, the lumbar multifidus (MF), has been associated with LBP and injuries in footballers. The size of the MF muscle has been shown to be modifiable with supervised motor-control training programs. Among AFL players, supervised motor-control training has also been shown to reduce the incidence of lower limb injuries and was associated with increased player availability for games. However, the effectiveness of a self-managed MF exercise program is unknown.Objective: To investigate the effect of self-managed exercises and fitness and strength training on MF muscle size in AFL players with or without current LBP.Design: Cross-sectional study.Setting: Professional AFL context.Patients or Other Participants: Complete data were available for 242 players from 6 elite AFL clubs.Intervention(s): Information related to the presence of LBP and history of injury was collected at the start of the preseason. At the end of the preseason, data were collected regarding performance of MF exercises as well as fitness and strength training. Ultrasound imaging of the MF muscle was conducted at the start and end of the preseason.Main Outcome Measure(s): Size of the MF muscles.Results: An interaction effect was found between performance of MF exercises and time (F = 13.89, P ≤ .001). Retention of MF muscle size was greatest in players who practiced the MF exercises during the preseason (F = 4.77, P = .03). Increased adherence to fitness and strength training was associated with retained MF muscle size over the preseason (F = 5.35, P = .02).Conclusions: Increased adherence to a self-administered MF exercise program and to fitness and strength training was effective in maintaining the size of the MF muscle in the preseason.


1970 ◽  
Vol 4 (2) ◽  
pp. 74-77
Author(s):  
Rukshana Ahmed ◽  
Shamim Ara

Pathological changes in the prostate gland occur commonly with advancing age including inflammation, atrophy, hyperplasia and carcinoma and a change in volume is also evident. Estimation of volume of prostate may be useful in a variety of clinical settings. A cross-sectional descriptive study was designed to see the changes in volume of the prostate with advancing age and done in the Department of Anatomy, Dhaka Medical College, Dhaka from August 2006 to June 2007. The study was performed on 70 post-mortem human prostates collected from the unclaimed dead bodies that were under examination in the Department of Forensic Medicine, Dhaka Medical College, Dhaka. The samples were divided into three age groups; group A (10-20 years), group B (21-40 years) and group C (41-70 years). Volume of the sample was measured by using the ellipsoid formula. The mean ± SD volume of prostate was 7.68 ± 3.64 cm3 in group A, 10.61 ± 3.99 cm3 in group B and 15.40 ± 6.31 cm3 in group C. Mean difference in volume between group A and group C, group B and group C were statistically significant (p<0.001). Statistically significant positive correlation was found between age and volume of prostate (r = + 0.579, p < 0.001). Key Words: Prostate; volume; Bangladeshi. DOI: 10.3329/imcj.v4i2.6501Ibrahim Med. Coll. J. 2010; 4(2): 74-77


Author(s):  
Kristen R. Choi ◽  
Tatum Stewart ◽  
Jewel D. Davies ◽  
Sara Naureckas ◽  
Angela Venegas-Murillo ◽  
...  

AbstractThe purpose of this study was to describe exposure to within-household and community adverse childhood experiences (ACEs) and to identify child- and parent-level factors associated with exposure to different kinds of ACEs. This cross-sectional study used a clinical sample of 257 Black and Hispanic children ages 3–16 years and their caregivers who were seeking care at two federally qualified health centers in Chicago, Illinois and screened positive for a behavioral health problem. The sample had high levels of within-household ACEs (76% reported at least one) and community ACEs (71% reported at least one). Black children experienced more overall and within-household ACEs than Hispanic children, including forced separation from a caregiver and family member incarceration. Hispanic children experienced more bullying and violent media exposure. Significant associations to all categories of ACEs were observed for depression, child behavioral problems, and older child age. Tailored assessment of ACEs and interventions such as trauma-informed care are needed in pediatric clinical settings, including assessment of ACEs children in experience in communities.


Author(s):  
Eduardo Sánchez-Sánchez ◽  
Ylenia Avellaneda-López ◽  
Esperanza García-Marín ◽  
Guillermo Ramírez-Vargas ◽  
Jara Díaz-Jimenez ◽  
...  

The aim of this study was to determine healthcare providers’ knowledge and practices about dysphagia. A descriptive cross-sectional study was carried out based on a self-administered and anonymous questionnaire addressed to healthcare providers in Spain. A total of 396 healthcare providers participated in the study. Of these, 62.3% knew the definition of dysphagia as a swallowing disorder. In addition, up to 39.2% of the participants reported that they did not know whether the EatingAssessmentTool (EAT-10) dysphagia screening test was usedin their own clinical settings. Similarly, up to 49.1% of them did not know the ClinicalExaminationVolume-Viscosity (MECV-V) method. Nearly all participants (98.8%) reported that thickeners must be used forall liquids administered to patients. A higher percentage of respondents based the choice of texture on patient’s tolerance (78.2%) rather than on the MECV-V result (17.3%). In addition,76.4% of the professionals had witnessed a bronchoaspiration; after it, 44.4% (n = 175) of them reported the appearance of pneumonia, and 14.5% (n = 57) the death of the patient (p = 0.005). The participants revealeda moderate/low knowledge ofthe definition, diagnosis, and clinical management of liquid dysphagia, which indicates some room for improvements.


Author(s):  
Chang Huang ◽  
Shuze Chen ◽  
Sheng Fu ◽  
Yingli Li ◽  
Zhenhao Li ◽  
...  

Abstract Purpose Prevention of ocular surface (OS) Demodex infestation plays an important role in OS hygiene and variety of factors may be associated with it, in which diabetes mellitus (DM) or dry eye disease (DED) has caught the attention of most scholars. However, there has been no research on whether there was a potential interaction between DM and DED in the process of OS Demodex infestation. This cross-sectional study was implemented in Zhujiang Hospital of Southern Medical University. Methods Ophthalmologic interviews, questionnaires, and examinations were conducted. Factors including general information, DM status, dry eye condition, etc. were collected to study the correlation of DM and DED on OS Demodex infestation. Results After statistical analysis, we found that both DM (P < 0.001) and DED (P = 0.013 < 0.05) are closely associated with OS Demodex infestation. Compared with DED, DM has higher priority association with OS Demodex infestation, and patients with both diseases have a significant higher risk of OS Demodex infestation (R = 0.197, P < 0.001). Meanwhile, age (R = 0.299, P < 0.001) and hypertension (P < 0.05) were also correlated with OS Demodex infestation. Conclusion This study provides a new evidence-based basis for clinical prevention and management of OS Demodex infestation.


2021 ◽  
Vol 10 (5) ◽  
pp. 988
Author(s):  
Nathaniel R. Johnson ◽  
Christopher J. Kotarsky ◽  
Kyle J. Hackney ◽  
Kara A. Trautman ◽  
Nathan D. Dicks ◽  
...  

Ultrasonography advantageously measures skeletal muscle size and quality, but some muscles may be too large to capture with standardized brightness mode (B-mode) imaging. Panoramic ultrasonography can capture more complete images and may more accurately measure muscle size. We investigated measurements made using panoramic compared to B-mode ultrasonography images of the rectus femoris with muscular performance. Concurrently, protein intake plays an important role in preventing sarcopenia; therefore, we also sought to investigate the association between animal-based protein intake (ABPI) and muscular performance. Ninety-one middle-aged adults were recruited. Muscle cross-sectional area (CSA) and thickness were obtained using B-mode and panoramic ultrasound and analyzed with Image J software. Muscular performance was assessed using isokinetic dynamometry, a 30-s chair test, and handgrip strength. Three-day food diaries estimated dietary intakes. Linear regression models determined relationships between measures from ultrasonography and muscular performance. Mixed linear models were used to evaluate the association between ABPI and muscular performance. Muscle CSA from panoramic ultrasonography and ABPI were positively associated with lower-body strength (β ± S.E.; CSA, 42.622 ± 20.024, p = 0.005; ABPI, 65.874 ± 19.855, p = 0.001), lower-body endurance (β ± S.E.; CSA, 595 ± 200.221, p = 0.001; ABPI, 549.944 ± 232.478, p = 0.020), and handgrip strength (β ± S.E.; CSA, 6.966 ± 3.328, p = 0.004; ABPI, 0.349 ± 0.171, p = 0.045). Panoramic ultrasound shows promise as a method for assessing sarcopenia. ABPI is related to better muscular performance.


2000 ◽  
Vol 278 (5) ◽  
pp. R1282-R1288 ◽  
Author(s):  
P. C. LaStayo ◽  
D. J. Pierotti ◽  
J. Pifer ◽  
H. Hoppeler ◽  
S. L. Lindstedt

Lengthening (eccentric) muscle contractions are characterized by several unusual properties that may result in unique skeletal muscle adaptations. In particular, high forces are produced with very little energy demand. Eccentrically trained muscles gain strength, but the specific nature of fiber size and composition is poorly known. This study assesses the structural and functional changes that occur to normal locomotor muscle after chronic eccentric ergometry at training intensities, measured as oxygen uptake, that do not influence the muscle when exercised concentrically. Male subjects trained on either eccentric or concentric cycle ergometers for 8 wk at a training intensity starting at 54% and ending at 65% of their peak heart rates. The isometric leg strength increased significantly in the eccentrically trained group by 36%, as did the cross-sectional area of the muscle fiber by 52%, but the muscle ultrastructure remained unchanged. There were no changes in either fiber size, composition, or isometric strength in the concentrically trained group. The responses of muscle to eccentric training appear to be similar to resistance training.


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