A group-based transdiagnostic sleep and circadian treatment for major depressive disorder: A randomized controlled trial.

OBJECTIVE: Sleep and circadian disturbance is highly comorbid with a range of psychological disorders, especially major depressive disorder (MDD). In view of the complexity of sleep and circadian problems in MDD, this study aimed to evaluate the efficacy of a group-based transdiagnostic intervention for sleep and circadian dysfunction (TranS-C) for improving depressive symptoms and sleep and circadian functions. METHOD: One hundred fifty-two adults diagnosed with comorbid MDD and sleep and circadian dysfunctions were randomized into TranS-C group treatment (TranS-C; n = 77) or care as usual (CAU; n = 75) control group. The TranS-C group received six weekly 2-hr group sessions of TranS-C, whereas the CAU group continued to receive usual care. Assessments were at baseline, immediate (Week 7), and 12-week (Week 19) posttreatment. Primary and secondary outcomes included depression, anxiety, sleep disturbances, fatigue, quality of life, and functional impairment. RESULTS: The TranS-C group showed significant improvement in depressive symptoms (p < .001, d = 0.84), insomnia severity (p < .001, d = 0.77), sleep disturbances (p < .001, d = 1.15), sleep-related impairment (p < .001, d = 1.22), fatigue (p < .001, d = 1.06), anxiety symptoms (p = .004, d = 0.67), quality of life (p < .001, d = 0.71), and sleep diary-derived parameters (ps < .05, d = 0.12-0.77) relative to the CAU group at immediate posttreatment. These treatment gains remained significant at 12-week follow-up. Significant improvement in functional impairment was also noted at 12-week follow-up. CONCLUSIONS: TranS-C was efficacious and acceptable in alleviating depressive symptoms and sleep and circadian disruptions in adults with MDD. The group format appears to be a low-cost, widely disseminable option to deliver TranS-C. Further research on TranS-C to examine its benefits on other psychiatric disorders is warranted. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Pathogen-associated gene discovery workflows for novel antivirulence therapeutic development.

Novel therapeutics to manage bacterial infections are urgently needed as the impact and prevalence of antimicrobial resistance (AMR) grows. Antivirulence therapeutics are an alternative approach to antibiotics that aim to attenuate virulence rather than target bacterial essential functions, while minimizing microbiota perturbation and the risk of AMR development. Beyond known virulence factors, pathogen-associated genes (PAGs; genes found only in pathogens to date) may play an important role in virulence or host association. Many identified PAGs encode uncharacterized hypothetical proteins and represent an untapped wealth of novel drug targets. Here, we review current advances in antivirulence drug research and development, including PAG identification, and provide a comprehensive workflow from the discovery of antivirulence drug targets to drug discovery. We highlight the importance of integrating bioinformatic/genomic-based methods for novel virulence factor discovery, coupled with experimental characterization, into existing drug screening platforms to develop novel and effective antivirulence drugs.

Muscle damage induced by maximal eccentric exercise of the elbow flexors after 3-week immobilization.

The present study investigated the effects of a 3-week immobilization (IM) on muscle damage induced by maximal eccentric exercise (MaxEC) to test the hypothesis that the IM would make muscles prone to muscle damage. Young healthy sedentary men were pseudo-randomly assigned to IM or control group (n = 12/group). Non-dominant arms of the IM group participants were immobilized at 90° elbow flexion by a cast for 21 days. All participants performed MaxEC consisting of five sets of six elbow flexor contractions by lowering a dumbbell set at 100% of pre-exercise maximal voluntary isometric contraction (MVC) strength of the non-dominant arm. This was performed at 2 days after the cast removal for the IM group. MVC torque, range of motion (ROM), muscle thickness (MT), muscle hardness, position sense (PS), and joint reaction angle (JRA) of the elbow flexors were measured at baseline, post-immobilization, and before, immediately after, and one to 5 days after MaxEC. The IM decreased MVC torque (-17 ± 2%), ROM (-2 ± 1%), MT (-7 ± 3%), and JRA (-12 ± 6%), and increased in muscle hardness (20 ± 6%) and PS (11 ± 2%) (p < 0.05). Changes in MVC (e.g., 2 days: -40 ± 5 vs. -30 ± 9%), ROM (2 days: -11 ± 2 vs. -9 ± 3%), muscle soreness (peak: 63 ± 22 vs. 48 ± 14 mm), plasma CK activity (peak: 7820 ± 4011 vs. 4980 ± 1363 IU/L), PS (maximal change: -23 ± 2 vs. -18 ± 3%), and JRA (maximal change: -37 ± 4 vs. -26 ± 3%) after MaxEC were greater (p < 0.05) for the IM than control group. These results supported the hypothesis and showed that the IM made the muscles more vulnerable to muscle damage induced by eccentric exercise.

The efficacy of integrated cognitive behavioral therapy (CBT) and acupressure versus CBT for insomnia: a three-arm pilot randomized controlled trial.

OBJECTIVES: This pilot study aimed to examine the efficacy of integrated cognitive behavioral therapy (CBT) and acupressure in treating insomnia and its daytime impairments in a Chinese adult population. METHODS: 40 eligible participants with insomnia were randomly assigned to either the integrated CBT and acupressure (CBTAcup) group (n = 14), the CBT group (n = 13), or the waitlist control (WL) group (n = 13). Participants in the CBTAcup group attended a 2-hour integrated CBT and self-administered acupressure group treatment once per week for six consecutive weeks, while participants in the CBT group attended six weekly 2-hour CBT for insomnia. Sleep, mood, daytime impairments, quality of life, and treatment credibility and adherence were assessed at baseline, immediate post-treatment (Week 7), and 4-week post-treatment (Week 11). RESULTS: Linear mixed-effects models showed that both the CBTAcup and CBT groups had significantly lower insomnia severity (d = -1.74 and d = -2.61), dysfunctional beliefs related to sleep (d = -2.17 and -2.76), and mental fatigue (d = -1.43 and -1.60) compared with the WL group at Week 7. The CBTAcup group provided additional benefits in reducing total fatigue (d = -1.43) and physical fatigue (d = -1.45). Treatment credibility was found to be improved in the CBTAcup group from baseline to Week 7. CONCLUSIONS: Integrated CBT and acupressure demonstrated comparable efficacy to pure CBT in treating insomnia symptoms, with additional advantages to improve fatigue symptoms and acceptability in the Chinese population. Further methodologically rigorous studies on a larger scale and longer follow-up are warranted to confirm these findings.

New horizons in understanding the experience of Chinese people living with dementia: a positive psychology approach.

As the global average age increases, the incidence of dementia is also rising. Given improvements in diagnosis and life expectancies, people now live longer with dementia. Thus, the wellbeing and quality of life among people living with dementia are increasingly important areas for research. Research with Western populations has recently begun to apply positive psychology concepts to understand wellbeing in people with dementia. Positive psychology focuses on positive emotions and traits that allow individuals to flourish and thrive-it highlights the possibility of positive subjective experiences in the face of loss and functional decline, and contrasts the traditional deficit-focused perception of dementia. Despite being a major driver in the global growth of dementia prevalence, there is a dearth of research using such positive concepts to understand people with dementia in non-Western communities. This review contains discussion of research on positive constructs in Chinese older adults, and parallels between traditional Chinese cultural values and positive psychology. On this basis, we propose the applicability of a positive psychology framework to Chinese people with dementia, and that 'harmony' is an important culturally specific concept to consider in this area of research. A positive psychology approach acknowledges that strengths and positive experiences can endure after dementia diagnosis. This not only adds to the under-researched area of lived experience of dementia in Chinese people, but highlights areas that could be the focus of interventions or measured as outcomes. By improving understanding, this approach also has potential to reduce carer burden and stigma around dementia.

Effect of oral rehydration solution versus spring water intake during exercise in the heat on muscle cramp susceptibility of young men.

BACKGROUND: Muscle cramp is a painful, involuntary muscle contraction, and that occurs during or following exercise is referred to as exercise-associated muscle cramp (EAMC). The causes of EAMC are likely to be multifactorial, but dehydration and electrolytes deficits are considered to be factors. This study tested the hypothesis that post-exercise muscle cramp susceptibility would be increased with spring water ingestion, but reduced with oral rehydration solution (ORS) ingestion during exercise. METHODS: Ten men performed downhill running (DHR) in the heat (35-36 °C) for 40-60 min to reduce 1.5-2% of their body mass in two conditions (spring water vs ORS) in a cross-over design. The body mass was measured at 20 min and every 10 min thereafter during DHR, and 30 min post-DHR. The participants ingested either spring water or ORS for the body mass loss in each period. The two conditions were counter-balanced among the participants and separated by a week. Calf muscle cramp susceptibility was assessed by a threshold frequency (TF) of an electrical train stimulation to induce cramp before, immediately after, 30 and 65 min post-DHR. Blood samples were taken before, immediately after and 65 min after DHR to measure serum sodium, potassium, magnesium and chroride concentrations, hematocrit (Hct), hemoglobin (Hb), and serum osmolarity. Changes in these varaibles over time were compared between conditions by two-way repeated measures of analysis of variance. RESULTS: The average (±SD) baseline TF (25.6 ± 0.7 Hz) was the same between conditions. TF decreased 3.8 ± 2.7 to 4.5 ± 1.7 Hz from the baseline value immediately to 65 min post-DHR for the spring water condition, but increased 6.5 ± 4.9 to 13.6 ± 6.0 Hz in the same time period for the ORS condition (P < 0.05). Hct and Hb did not change significantly (P > 0.05) for both conditions, but osmolarity decreased (P < 0.05) only for the spring water condition. Serum sodium and chloride concentrations decreased (< 2%) at immediately post-DHR for the spring water condition only (P < 0.05). CONCLUSIONS: These results suggest that ORS intake during exercise decreased muscle cramp susceptibility. It was concluded that ingesting ORS appeared to be effective for preventing EAMC.

Effects of wrist position on eccentric exercise-induced muscle damage of the elbow flexors.

We tested the hypothesis that the magnitude of changes in indirect muscle damage markers would be greater after maximal elbow flexor eccentric exercise in the supinated (shorter biceps brachii) than neutral wrist (longer) position, and the difference in the magnitude would be associated with greater elongation over contractions for the supinated than neutral position, rather than the initial muscle length. Ten untrained men (21-39 years) performed two bouts of 10 sets of 6 maximal isokinetic eccentric contractions of the elbow flexors in the supinated position for one arm and neutral position for the other arm separated by 2 weeks in a randomized order. Biceps brachii myotendinous junction (MTJ) movements during eccentric contractions were recorded by B-mode ultrasonography, and the displacement from the start to end of each contraction was quantified. Peak torque (supinated: 367.8 ± 112.5 Nm, neutral: 381.5 ± 120.4 Nm) and total work (1816 ± 539 J, 1865 ± 673 J) produced during eccentric contractions were similar between conditions. The average MTJ displacement increased (P < .05) from the 1st set (8.0 ± 2.0 mm) to 10th set (15.8 ± 1.9 mm) for the supinated condition, but no such increase was found in the neutral condition (1st set: 5.1 ± 1.0 mm, 10th set: 5.0 ± 0.8 mm). Changes in indirect muscle damage markers (maximal voluntary isometric contraction torque, range of motion, serum creatine kinase activity, and muscle soreness) after exercise were greater (P < .05) for the supinated than neutral condition. These results suggest that the greater muscle damage marker changes for the supinated than neutral wrist position was associated with the greater muscle lengthening (strain).

PSORTdb 4.0: expanded and redesigned bacterial and archaeal protein subcellular localization database incorporating new secondary localizations.

Protein subcellular localization (SCL) is important for understanding protein function, genome annotation, and aids identification of potential cell surface diagnostic markers, drug targets, or vaccine components. PSORTdb comprises ePSORTdb, a manually curated database of experimentally verified protein SCLs, and cPSORTdb, a pre-computed database of PSORTb-predicted SCLs for NCBI's RefSeq deduced bacterial and archaeal proteomes. We now report PSORTdb 4.0 (http://db.psort.org/). It features a website refresh, in particular a more user-friendly database search. It also addresses the need to uniquely identify proteins from NCBI genomes now that GI numbers have been retired. It further expands both ePSORTdb and cPSORTdb, including additional data about novel secondary localizations, such as proteins found in bacterial outer membrane vesicles. Protein predictions in cPSORTdb have increased along with the number of available microbial genomes, from approximately 13 million when PSORTdb 3.0 was released, to over 66 million currently. Now, analyses of both complete and draft genomes are included. This expanded database will be of wide use to researchers developing SCL predictors or studying diverse microbes, including medically, agriculturally and industrially important species that have both classic or atypical cell envelope structures or vesicles.

Effect of preconditioning exercise on biceps brachii myotendinous junction displacement during elbow flexor eccentric exercise.

The present study tested the hypothesis that 30 low-intensity (10%) eccentric contractions (10%EC) or two maximal voluntary isometric contractions at a long muscle length (2MVIC) that were performed at two days before maximal eccentric exercise of the elbow flexors consisting of five sets of six maximal eccentric contractions (MaxEC) would reduce increases in biceps brachii distal myotendinous junction displacement (MTJd) over the eccentric contractions during MaxEC. Sedentary young men were randomly placed (n = 12/group) to a control group that performed two bouts of MaxEC (CONT-1st, CONT-2nd) separated by two weeks, or one of two preconditioning groups that performed 10%EC or 2MVIC at 20° elbow flexion at two days prior to MaxEC. All exercises were performed by the non-dominant arm. MTJd of each contraction was assessed by B-mode ultrasound, and its changes over sets were compared among the groups. The average MTJd from the start to the end of six eccentric contractions in the first set was similar among the groups (6.4 ± 0.7 mm). The MTJd increased from the first to fifth set, but the increase was smaller (P < .05) for the 10%EC (13 ± 6%) and 2MVIC (16 ± 9%) groups, and CONT-2nd (3 ± 6%) when compared with CONT-1st (60 ± 12%). Both 10%EC and 2MVIC groups showed smaller (P < .05) changes in all muscle damage markers after MaxEC similarly when compared with CONT-1st, but the changes were greater than those after CONT-2nd. These results supported the hypothesis that protective effect was associated with less MTJd changes, suggesting that this is associated with the mechanisms underpinning the preconditioning effect on muscle damage.

Metagenome-assembled genome binning methods with short reads disproportionately fail for plasmids and genomic Islands.

Metagenomic methods enable the simultaneous characterization of microbial communities without time-consuming and bias-inducing culturing. Metagenome-assembled genome (MAG) binning methods aim to reassemble individual genomes from this data. However, the recovery of mobile genetic elements (MGEs), such as plasmids and genomic islands (GIs), by binning has not been well characterized. Given the association of antimicrobial resistance (AMR) genes and virulence factor (VF) genes with MGEs, studying their transmission is a public-health priority. The variable copy number and sequence composition of MGEs makes them potentially problematic for MAG binning methods. To systematically investigate this issue, we simulated a low-complexity metagenome comprising 30 GI-rich and plasmid-containing bacterial genomes. MAGs were then recovered using 12 current prediction pipelines and evaluated. While 82-94 % of chromosomes could be correctly recovered and binned, only 38-44 % of GIs and 1-29 % of plasmid sequences were found. Strikingly, no plasmid-borne VF nor AMR genes were recovered, and only 0-45 % of AMR or VF genes within GIs. We conclude that short-read MAG approaches, without further optimization, are largely ineffective for the analysis of mobile genes, including those of public-health importance, such as AMR and VF genes. We propose that researchers should explore developing methods that optimize for this issue and consider also using unassembled short reads and/or long-read approaches to more fully characterize metagenomic data.

Evidence for transmission of COVID-19 prior to symptom onset.

We collated contact tracing data from COVID-19 clusters in Singapore and Tianjin, China and estimated the extent of pre-symptomatic transmission by estimating incubation periods and serial intervals. The mean incubation periods accounting for intermediate cases were 4.91 days (95%CI 4.35, 5.69) and 7.54 (95%CI 6.76, 8.56) days for Singapore and Tianjin, respectively. The mean serial interval was 4.17 (95%CI 2.44, 5.89) and 4.31 (95%CI 2.91, 5.72) days (Singapore, Tianjin). The serial intervals are shorter than incubation periods, suggesting that pre-symptomatic transmission may occur in a large proportion of transmission events (0.4-0.5 in Singapore and 0.6-0.8 in Tianjin, in our analysis with intermediate cases, and more without intermediates). Given the evidence for pre-symptomatic transmission, it is vital that even individuals who appear healthy abide by public health measures to control COVID-19.

The first cases of COVID-19 were identified in Wuhan, a city in Central China, in December 2019. The virus quickly spread within the country and then across the globe. By the third week in January, the first cases were confirmed in Tianjin, a city in Northern China, and in Singapore, a city country in Southeast Asia. By late February, Tianjin had 135 cases and Singapore had 93 cases. In both cities, public health officials immediately began identifying and quarantining the contacts of infected people. The information collected in Tianjin and Singapore about COVID-19 is very useful for scientists. It makes it possible to determine the disease's incubation period, which is how long it takes to develop symptoms after virus exposure. It can also show how many days pass between an infected person developing symptoms and a person they infect developing symptoms. This period is called the serial interval. Scientists use this information to determine whether individuals infect others before showing symptoms themselves and how often this occurs. Using data from Tianjin and Singapore, Tindale, Stockdale et al. now estimate the incubation period for COVID-19 is between five and eight days and the serial interval is about four days. About 40% to 80% of the novel coronavirus transmission occurs two to four days before an infected person has symptoms. This transmission from apparently healthy individuals means that staying home when symptomatic is not enough to control the spread of COVID-19. Instead, broad-scale social distancing measures are necessary. Understanding how COVID-19 spreads can help public health officials determine how to best contain the virus and stop the outbreak. The new data suggest that public health measures aimed at preventing asymptomatic transmission are essential. This means that even people who appear healthy need to comply with preventive measures like mask use and social distancing.

PSORTm: a bacterial and archaeal protein subcellular localization prediction tool for metagenomics data.

MOTIVATION: Many methods for microbial protein subcellular localization (SCL) prediction exist; however, none is readily available for analysis of metagenomic sequence data, despite growing interest from researchers studying microbial communities in humans, agri-food relevant organisms and in other environments (e.g. for identification of cell-surface biomarkers for rapid protein-based diagnostic tests). We wished to also identify new markers of water quality from freshwater samples collected from pristine versus pollution-impacted watersheds. RESULTS: We report PSORTm, the first bioinformatics tool designed for prediction of diverse bacterial and archaeal protein SCL from metagenomics data. PSORTm incorporates components of PSORTb, one of the most precise and widely used protein SCL predictors, with an automated classification by cell envelope. An evaluation using 5-fold cross-validation with in silico-fragmented sequences with known localization showed that PSORTm maintains PSORTb's high precision, while sensitivity increases proportionately with metagenomic sequence fragment length. PSORTm's read-based analysis was similar to PSORTb-based analysis of metagenome-assembled genomes (MAGs); however, the latter requires non-trivial manual classification of each MAG by cell envelope, and cannot make use of unassembled sequences. Analysis of the watershed samples revealed the importance of normalization and identified potential biomarkers of water quality. This method should be useful for examining a wide range of microbial communities, including human microbiomes, and other microbiomes of medical, environmental or industrial importance. AVAILABILITY AND IMPLEMENTATION: Documentation, source code and docker containers are available for running PSORTm locally at https://www.psort.org/psortm/ (freely available, open-source software under GNU General Public License Version 3). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Water intake after dehydration makes muscles more susceptible to cramp but electrolytes reverse that effect.

OBJECTIVE: No previous study has compared water and oral rehydration solution (ORS) intake after dehydration induced by exercise in the heat for the effect on muscle cramps. The present study tested the hypothesis that water ingestion after dehydration would increase muscle cramp susceptibility, but this would be prevented by ORS ingestion. METHODS: Ten men performed two bouts of downhill running (DHR; -5%) in the heat (35°C-36 °C) until their body mass was reduced by 2%. Ten minutes after DHR, either spring water or electrolyte water similar to ORS (OS-1®) was ingested in a counter-balanced order on two different days separated by a week. Muscle cramp susceptibility was assessed by a threshold frequency (TF) of electrical train stimulation to induce cramp before, immediately after (0), and 30 and 60 min after the ingestion. Blood samples were taken before, immediately and 80 min after DHR to measure serum electrolyte concentrations. RESULTS: Muscle cramp susceptibility assessed by TF did not change from baseline to immediately after DHR for both conditions (water: 24.6 ± 2.1 Hz, OS-1®: 24.7 ± 1.4 Hz). TF decreased after water intake by 4.3 Hz (30 min) and 5.1 Hz (60 min post-ingestion), but increased after OS-1® intake by 3.7 and 5.4 Hz, respectively. Serum sodium and chloride concentrations decreased after water intake but maintained after OS-1® intake. CONCLUSION: These results suggest that water intake after dehydration makes muscles more susceptible to electrical simulation-induced muscle cramp, probably due to dilution of electrolytes, and when OS-1® is consumed, the susceptibility to muscle cramp decreases.

Relationship between isometric contraction intensity and muscle hardness assessed by ultrasound strain elastography.

INTRODUCTION: Ultrasound elastography is used to assess muscle hardness or stiffness; however, no previous studies have validated muscle hardness measures using ultrasound strain elastography (SE). This study investigated the relationship between plantar flexor isometric contraction intensity and gastrocnemius hardness assessed by SE. We hypothesised that the muscle would become harder linearly with an increase in the contraction intensity of the plantar flexors. METHODS: Fifteen young women (20.1 ± 0.8 years) performed isometric contractions of the ankle plantar flexors at four different intensities (25, 50, 75, 100% of maximal voluntary contraction force: MVC) at 0° plantar flexion. Using SE images, the strain ratio (SR) between the muscle and an acoustic coupler (elastic modulus 22.6 kPa) placed over the skin was calculated (muscle/coupler); pennation angle and muscle thickness were measured for the resting and contracting conditions. RESULTS: SR decreased with increasing contraction intensity from rest (1.28 ± 0.20) to 25% (0.99 ± 0.21), 50% (0.61 ± 0.15), 75% (0.34 ± 0.1) and 100% MVC (0.20 ± 0.05). SR decreased linearly (P < 0.05) with increasing MVC from rest to 75% MVC, but levelled off from 75 and 100% MVC. SR was negatively correlated with pennation angle (r = -0.80, P < 0.01) and muscle thickness ( r= -0.78, P< 0.01). CONCLUSION: SR appears to represent muscle hardness changes in response to contraction intensity changes, in the assumption that the gastrocnemius muscle contraction intensity is proportional to the plantar flexion intensity. We concluded that gastrocnemius muscle hardness changes could be validly assessed by SR, and the force-hardness relationship was not linear.

Assessment of Muscle Pain Induced by Elbow-Flexor Eccentric Exercise.

CONTEXT: Delayed-onset muscle soreness (DOMS) is a common muscle pain that many people experience and is often used as a model of acute muscle pain. Researchers have reported the effects of various interventions on DOMS, but different DOMS assessment protocols used in these studies make it difficult to compare the effects. OBJECTIVE: To investigate DOMS characteristics after elbow-flexor eccentric exercise to establish a standardized DOMS assessment protocol. DESIGN: Descriptive laboratory study. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Ten healthy, untrained men (21-39 years). INTERVENTION(S): Participants performed 10 sets of 6 maximal isokinetic eccentric contractions of the elbow flexors. MAIN OUTCOME MEASURE(S): Indirect muscle-damage markers were maximal voluntary isometric contraction torque, range of motion, and serum creatine kinase activity. Muscle pain was assessed before exercise, immediately postexercise, and 1 to 5 days postexercise using (1) a visual analog scale (VAS), (2) a category ratio-10 scale (CR-10) when applying static pressure and palpation at different sites (3, 9, and 15 cm above the elbow crease), and (3) pressure-pain thresholds (PPTs) at 50 sites (pain mapping). RESULTS: Maximal voluntary isometric contraction and range of motion decreased and creatine kinase activity increased postexercise, indicating muscle damage. Palpation induced greater pain than static pressure, and longitudinal and transverse palpations induced greater pain than circular palpation (P < .05). The PPT was lower in the medial region before exercise, but the pain-sensitive regions shifted to the central and distal regions of the biceps brachii at 1 to 3 days postexercise (P < .05). The VAS was correlated with the CR-10 scale (r = 0.91, P < .05) but not with the PPT (r = -0.28, P = .45). CONCLUSIONS: The way in which muscles are assessed affects the pain level score. This finding suggests that pain level and pain threshold cannot be used interchangeably and that the central and distal regions of the biceps brachii should be included in DOMS assessment using the VAS, CR-10 scale, and PPT after elbow-flexor eccentric exercise.

Reduced muscle lengthening during eccentric contractions as a mechanism underpinning the repeated-bout effect.

This study investigated biceps brachii distal myotendinous junction (MTJ) displacement during maximal eccentric elbow flexor contractions to test the hypothesis that muscle length change would be smaller (less MTJ displacement) during the second than the first exercise bout. Ten untrained men performed two eccentric exercise bouts (ECC1 and ECC2) with the same arm consisting of 10 sets of six maximal isokinetic (60°/s) eccentric elbow flexor contractions separated by 4 wk. Biceps brachii distal MTJ displacement was assessed using B-mode ultrasonography, and changes in the displacement (muscle length change) from the start to the end of each contraction during each set and over 10 sets were compared between bouts by two-way repeated-measures ANOVA. Several indirect muscle damage markers were also measured and compared between bouts by two-way repeated-measures ANOVA. The magnitude of MTJ displacement (average of six contractions) increased from set 1 (8.2 ± 4.7 mm) to set 10 (16.4 ± 4.7 mm) during ECC1 (P < 0.05), but no significant changes over sets were evident during ECC2 (set 1: 8.5 ± 4.0 mm; set 10: 9.3 ± 3.1 mm). Changes in maximal voluntary isometric contraction strength, range of motion, muscle thickness, ultrasound echo intensity, serum creatine kinase activity, and muscle soreness (visual analog scale) were smaller (P < 0.05) following ECC2 than ECC1, showing less damage in the repeated bout. These results indicate that the magnitude of muscle lengthening was less during the second than the first eccentric exercise bout, which appears to be a mechanism underpinning the repeated-bout effect.

Pacing strategies during the swim, cycle and run disciplines of sprint, Olympic and half-Ironman triathlons.

PURPOSE: This study investigated the influence of distance on self-selected pacing during the swim, cycle and run disciplines of sprint, Olympic and half-Ironman (HIM) distance triathlon races. METHOD: Eight trained male triathletes performed the three individual races in <2 months. Participants' bikes were fitted with Schoberer Rad Meßtechnik to monitor speed, power output and heart rate during the cycle discipline. Global positioning system was worn to determine speed and heart rate during the swim and run disciplines. RESULT: An even swim pacing strategy was adopted across all distances. A more stochastic pacing was observed during the HIM cycle [standard deviation of exposure variation analysis (EVASD) = 3.21 ± 0.61] when compared with the sprint cycle discipline (EVASD = 3.84 ± 0.44, p = 0.018). Only 20.9 ± 4.1 % of the cycling time was spent more than 10 % above the mean power output in the HIM, compared with 43.8 ± 2.9 % (p = 0.002) and 37.7 ± 11.1 % (p = 0.039) during the sprint and Olympic distance triathlons, respectively. Conversely, 13.6 ± 5.1 % of the cycling time was spent 5-10 % below the mean power output during the HIM, compared with 5.9 ± 1.2 % (p = 0.034) and 8.0 ± 5.1 % (p = 0.045) during the sprint and Olympic distance triathlons, respectively. A negative pacing strategy was adopted during the sprint distance run, compared with positive pacing strategy during the Olympic and HIM. CONCLUSION: Results of this study suggest that pacing strategies during triathlon are highly influenced by distance and discipline, and highlight the importance of developing pacing strategies based on distance, strengths and individual fitness.

Changes in electrical pain threshold of fascia and muscle after initial and secondary bouts of elbow flexor eccentric exercise.

PURPOSE: This study investigated changes in electrical pain threshold (EPT) after repeated eccentric exercise bouts to test the hypothesis that fascia would become more sensitive than muscle when greater delayed onset muscle soreness (DOMS) is induced. METHODS: Ten young men performed two eccentric exercise bouts (ECC1, ECC2) consisting of ten sets of six maximal isokinetic eccentric contractions of the elbow flexors with the same arm separated by 4 weeks. Maximal voluntary isometric contraction torque, range of motion, muscle soreness assessed by a visual analogue scale (VAS) and pressure pain threshold (PPT) were measured before, immediately after and 1-5 days after exercise. EPT was assessed in the biceps brachii fascia (BBF), biceps brachii muscle, and brachialis fascia (BF) 1 day before, immediately after, and 1, 2 and 4 days after exercise. RESULTS: All measures showed smaller changes (P < 0.05) after ECC2 than ECC1. EPT decreased after both bouts and the largest decreases were evident at 2 days post-exercise (P < 0.05). The decreases in EPT after ECC1 were greater (P < 0.05) for both BBF (Baseline: 1.45 ± 0.23 mA, 2 days post-exercise: 0.13 ± 0.11 mA) and BF (1.64 ± 0.29 mA, 0.26 ± 0.2 mA) than muscle (1.56 ± 0.29 mA, 0.69 ± 0.33 mA). Changes in EPT were correlated with the changes in PPT (r = 0.63-0.87, P ≤ 0.05) but not with VAS (r = -0.01 to 0.50). CONCLUSION: These results show that fascia becomes more sensitive than muscle to electrical stimulation after the initial eccentric exercise, suggesting that damage inflammation to fascia than muscle fibres is more associated with DOMS.

Effect of vibration treatment on symptoms associated with eccentric exercise-induced muscle damage.

OBJECTIVE: : The aim of this study was to test the hypothesis that vibration treatment reduces delayed-onset muscle soreness and swelling and enhances recovery of muscle function after eccentric exercise. DESIGN: : A randomized crossover design was used. Fifteen young men performed ten sets of six maximal eccentric contractions of the elbow flexors with the right arm for one occasion and the left arm for the other occasion separated by 4 wks. One arm received a 30-min vibration treatment at 30 mins after and 1, 2, 3, and 4 days after the exercise (treatment group), and the other arm did not receive any treatment (control group). The order of the treatment and control conditions and the use of the dominant and nondominant arms were counterbalanced among subjects. Changes in indirect markers of muscle damage were compared between arms by a two-way repeated-measures analysis of variance. RESULTS: : Compared with the control group, the treatment group showed significantly (P < 0.05) less development and faster reduction in delayed-onset muscle soreness at 2 to 5 days after exercise. The recovery of range of motion was significantly (P < 0.05) faster for the treatment than for the control group. However, no significant effects on the recovery of muscle strength and serum creatine kinase activity were evident. Immediately after the vibration treatment, a significant (P < 0.05) decrease in the magnitude of delayed-onset muscle soreness and muscle strength and an increase in pressure pain threshold and range of motion were found. CONCLUSIONS: : These results showed that the vibration treatment was effective for attenuation of delayed-onset muscle soreness and recovery of range of motion after strenuous eccentric exercise but did not affect swelling, recovery of muscle strength, and serum creatine kinase activity.