Abstract Objectives Fluctuating endogenous and exogenous ovarian hormones may influence exercise parameters; yet control and verification of ovarian hormone status is rarely reported and limits ...current exercise science and sports medicine research. The purpose of this study was to determine the effectiveness of an individualised three-step method in identifying the mid-luteal or high hormone phase in endogenous and exogenous hormone cycles in recreationally-active women and determine hormone and demographic characteristics associated with unsuccessful classification. Design Cross-sectional study design. Methods Fifty-four recreationally-active women who were either long-term oral contraceptive users (n = 28) or experiencing regular natural menstrual cycles (n = 26) completed step-wise menstrual mapping, urinary ovulation prediction testing and venous blood sampling for serum/plasma hormone analysis on two days, six to 12 days after positive ovulation prediction to verify ovarian hormone concentrations. Results Mid-luteal phase was successfully verified in 100% of oral contraceptive users, and 70% of naturally-menstruating women. Thirty percent of participants were classified as luteal phase deficient; when excluded, the success of the method was 89%. Lower age, body fat and longer menstrual cycles were significantly associated with luteal phase deficiency. Conclusions A step-wise method including menstrual cycle mapping, urinary ovulation prediction and serum/plasma hormone measurement was effective at verifying ovarian hormone status. Additional consideration of age, body fat and cycle length enhanced identification of luteal phase deficiency in physically-active women. These findings enable the development of stricter exclusion criteria for female participants in research studies and minimise the influence of ovarian hormone variations within sports and exercise science and medicine research.
Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this.
To examine whether a calcium-rich pre-exercise meal attenuates ...exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses.
Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique.
PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 1.20, 2.01 times lower in CAL immediately post-exercise and 1.45 1.12, 1.88 times lower at 40 min post-exercise. CTX-I was 1.40 1.15, 1.70 times lower in CAL at immediately post-exercise, 1.30 1.07, 1.57 times lower at 40 min post-exercise and 1.22 1.00, 1.48 times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819).
This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption--PTH and CTX-I.
Australian New Zealand Clinical Trials Registry ACTRN12614000675628.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Productivity-diversity relationships (P/D) are a vital theme in ecology, but productivity is typically not measured directly in that research. Instead, biomass (B) is the most common proxy for ...productivity, often as a 1:1 substitute. Unfortunately, this practice may cause error and uncertainty in P/D research, due to the fundamental difference between B and P and variable P/B ratios among and within systems. As a result, P/D research often measures a B/D relationship but interprets it as P/D. Fortunately, plausible, statistically legitimate and predictive P/B relationships can be found with careful analyses based on model selection of alternative allometric scaling equations and tests of model assumptions. Analyses are presented here for P/B relationships of 19 data sets, ranging from plant and animal populations and assemblages to ecosystems and biomes, representing over 2,300 analyzed P/B data. Models included standardized major regression (SMA) and ordinary least squares (OLS) regressions. Simple linear 1:1 P/B relationships are never supported. Instead, logP-logB transformed data, consistent with allometric scaling approaches, are far more common as the most plausible, statistically legitimate and predictive models. Given these relationships, many P/D studies with only B data may now better estimate P with SMA models, while studies with P and B data in some plots may estimate P in parallel plots with B and D data by using OLS models. Two grassland examples are re-analyzed to evaluate the importance of this approach to P/D research when B was used as a proxy for P; in one case, P had been underestimated by 20%; in the other case, P had been overestimated by 20%. The difference is related to underlying sampling methods and obtained data. The approach presented here may help productivity-diversity research resolve some uncertainty to better understand effects of ecological diversity on biomass production.
Abstract Objectives : To investigate the relationship between training load and injury in professional rugby league players; Design : Prospective cohort study; Methods : Seventy-nine professional ...rugby league players (mean ± SD age, 23.3 ± 3.8 years) participated in this four-year study. A periodized field, strength, and power training program was implemented, with training loads progressively increased in the general preparatory phase of the season and reduced during the competitive phase of the season. Training loads and injuries were recorded for each training session. Results : Training load was significantly related ( P < 0.05) to overall injury ( r = 0.82), non-contact field injury ( r = 0.82), and contact field injury ( r = 0.80) rates. Significant relationships were also observed between the field training load and overall field injury ( r = 0.68), non-contact field injury ( r = 0.65), and contact field injury ( r = 0.63) rates. Strength and power training loads were significantly related to the incidence of strength and power injuries ( r = 0.63). There was no significant relationship between field training loads and the incidence of strength and power injuries. However, strength and power training loads were significantly ( P < 0.01) associated with the incidence of contact ( r = 0.75) and non-contact ( r = 0.82) field training injuries. Conclusions : These findings suggest that the harder rugby league players train, the more injuries they will sustain, and that high strength and power training loads may contribute indirectly to field injuries. Monitoring of training loads and careful scheduling of field and gymnasium sessions to avoid residual fatigue is warranted to minimize the effect of training-related injuries on professional rugby league players.
Tertiary lymphoid structures (TLSs) display phenotypic and functional characteristics of secondary lymphoid organs, and often develop in tissues affected by chronic inflammation, as well as in ...certain inflammation‐associated cancers where they are prognostic of improved patient survival. However, the mechanisms that govern the development of tumour‐associated TLSs remain ill‐defined. Here, we observed tumour‐associated TLSs in a preclinical mouse model (gp130F/F) of gastric cancer, where tumourigenesis is dependent on hyperactive STAT3 signalling through the common IL‐6 family signalling receptor, gp130. Gastric tumourigenesis was associated with the development of B and T cell‐rich submucosal lymphoid aggregates, containing CD21+ cellular networks and high endothelial venules. Temporally, TLS formation coincided with the development of gastric adenomas and induction of homeostatic chemokines including Cxcl13, Ccl19 and Ccl21. Reflecting the requirement of gp130‐driven STAT3 signalling for gastric tumourigenesis, submucosal TLS development was also STAT3‐dependent, but independent of the cytokine IL‐17 which has been linked with lymphoid neogenesis in chronic inflammation and autoimmunity. Interestingly, upregulated lymphoid chemokine expression and TLS formation were also observed in a chronic gastritis model induced by Helicobacter felis infection. Tumour‐associated TLSs were also observed in patients with intestinal‐type gastric cancer, and a gene signature linked with TLS development in gp130F/F mice was associated with advanced clinical disease, but was not prognostic of patient survival. Collectively, our in vivo data reveal that hyperactive gp130‐STAT3 signalling closely links gastric tumourigenesis with lymphoid neogenesis, and while a TLS gene signature was associated with advanced gastric cancer in patients, it did not indicate a favourable prognosis.
What's new?
Tertiary lymphoid structures (TLSs) develop in chronically inflamed tissues, and have been associated with improved survival in certain cancer patients. Here, the authors examined mechanisms governing the development of submucosal TLSs in the gp130F/F mouse model of gastric cancer and in patients afflicted with intestinal‐type disease. TLS formation was observed both mice and patients but a TLS gene signature identified in mice did not predict improved patient survival, pointing to need for more research into TLSs and gastric cancer prognosis.
We report the distribution of planets as a function of planet radius, orbital period, and stellar effective temperature for orbital periods less than 50 days around solar-type (GK) stars. These ...results are based on the 1235 planets (formally "planet candidates") from the Kepler mission that include a nearly complete set of detected planets as small as 2 R. For all planets with orbital periods less than 50 days, we measure occurrence of 0.130 + or - 0.008, 0.023 + or - 0.003, and 0.013 + or - 0.002 planets per star for planets with radii 2-4, 4-8, and 8-32 R, in agreement with Doppler surveys. We fit occurrence as a function of P to a power-law model with an exponential cutoff below a critical period Psub 0. For smaller planets, Psub 0 has larger values, suggesting that the "parking distance" for migrating planets moves outward with decreasing planet size.
While the physiological adaptations that occur following endurance training in previously sedentary and recreationally active individuals are relatively well understood, the adaptations to training ...in already highly trained endurance athletes remain unclear. While significant improvements in endurance performance and corresponding physiological markers are evident following submaximal endurance training in sedentary and recreationally active groups, an additional increase in submaximal training (i.e. volume) in highly trained individuals does not appear to further enhance either endurance performance or associated physiological variables e.g. peak oxygen uptake (VO2peak), oxidative enzyme activity. It seems that, for athletes who are already trained, improvements in endurance performance can be achieved only through high-intensity interval training (HIT). The limited research which has examined changes in muscle enzyme activity in highly trained athletes, following HIT, has revealed no change in oxidative or glycolytic enzyme activity, despite significant improvements in endurance performance (p < 0.05). Instead, an increase in skeletal muscle buffering capacity may be one mechanism responsible for an improvement in endurance performance. Changes in plasma volume, stroke volume, as well as muscle cation pumps, myoglobin, capillary density and fibre type characteristics have yet to be investigated in response to HIT with the highly trained athlete. Information relating to HIT programme optimisation in endurance athletes is also very sparse. Preliminary work using the velocity at which VO2max is achieved (V(max)) as the interval intensity, and fractions (50 to 75%) of the time to exhaustion at V(max) (T(max)) as the interval duration has been successful in eliciting improvements in performance in long-distance runners. However, V(max) and T(max) have not been used with cyclists. Instead, HIT programme optimisation research in cyclists has revealed that repeated supramaximal sprinting may be equally effective as more traditional HIT programmes for eliciting improvements in endurance performance. Further examination of the biochemical and physiological adaptations which accompany different HIT programmes, as well as investigation into the optimal HIT programme for eliciting performance enhancements in highly trained athletes is required.
Cancer-related fatigue (CRF) is a prevalent and persistent symptom from androgen deprivation therapy (ADT) in prostate cancer. The Mediterranean-style dietary pattern (MED-diet) offers a plausible ...mechanism to mitigate CRF through reducing inflammation and improving body composition. This study aimed to evaluate the effects of a 12-week MED-diet, compared to usual care, on CRF and quality of life in men with prostate cancer treated with ADT.
Twenty-three men (65.9 ± 7.8 years; body mass index: 29.6 ± 2.7 kg/m2; ADT duration: 33.8 ± 35.6 months) receiving ADT for ≥3 months were randomly assigned (1:1) to 12-weeks of usual care or the MED-diet involving six individualised nutrition consults. Primary outcomes included CRF Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scale (FACIT-F) and quality of life FACIT-General (FACIT-G), secondary outcomes included body mass/composition and interleukin (IL)-6 and IL-8 concentrations measured at baseline, 8-weeks and 12 weeks. Intervention feasibility was measured by intervention safety, study completion rate, consult attendance, and adherence to the MED-diet through the Mediterranean-diet adherence screener (MEDAS). Intention to treat linear mixed models were used to determine changes in outcomes between the MED-diet and usual care at baseline, 8-weeks and 12-weeks.
The MED-diet improved CRF (FACIT-F) at 8-weeks +4.8 (0.0, 9.8); P = 0.05 and 12-weeks +7.2 (2.2, 12.0); P = 0.005, quality of life (FACIT-G) at 12-weeks +9.2 (2.7, 15.8); P = 0.006, reduced total body mass at 8-weeks −2.51 kg (−4.25, −0.78); P = 0.005 and 12-weeks -2.97 kg (−4.71, −1.25); P = 0.001, lean mass at 8-weeks −1.50 kg (−2.91, −0.10); P = 0.036, and IL-8 at 8-weeks -0.18 ng/ml (−0.34, −0.02); P = 0.029 compared to usual care. The MED-diet demonstrated zero adverse events, 91% study completion, 100% attendance, and 81% adherence to the MEDAS.
The MED-diet is safe and feasible, and has the potential to improve CRF and quality of life in overweight men treated with ADT compared to usual care. Further exploration of the MED-diet is warranted in a larger powered sample size to consolidate these findings.
BACKGROUND:The use of a trabecular metal revision shell with metal augmentation to fill segmental or irregular defects during complex revision hip arthroplasty has been shown to provide good ...short-term results in prior published series. Longer-term results of the several cup-augment constructs used clinically are not known. The objective of this study was to report, with minimum 5-year radiographic and clinical follow-up, the outcome of these various constructs in revision total hip arthroplasty.
METHODS:Eighty-four patients (85 hips) underwent revision total hip arthroplasty with use of porous tantalum augments between 2000 and 2007 at a single institution and were retrospectively reviewed. Fifty-seven of the patients (58 hips) had clinical and radiographic follow-up at a minimum of 5 years. At the time of revision, the majority of the hips had acetabular defects classified as Paprosky Type 3A (28 of 58, 48%) or Type 3B (22 of 58, 38%). Eleven (19%) of the hips also had preoperative pelvic discontinuity. All hips were assessed clinically at a minimum of 5 years with use of the Mayo hip score. Postoperative radiographs were reviewed for implant stability, the presence and location of radiolucent lines and healing of the discontinuity if present.
RESULTS:In 2 (3%) of the 58 hips, the constructs failed because of aseptic loosening of the acetabular component and re-revision was indicated. Six (10%) of the 58 hips demonstrated a radiolucent line between the trabecular metal shell and bone in DeLee and Charnley zone 3. In 1 hip that underwent re-revision and in 5 of the 6 hips with a zone-3 radiolucency, a pelvic discontinuity was present at the time of the index revision. The mean preoperative Mayo hip score was 35.7, which improved to 61.9 at 3 months and was 61.7 at the minimum 5-year follow-up.
CONCLUSIONS:With failure defined as aseptic loosening requiring repeat revision surgery, this cohort demonstrated 97% survivorship and maintained satisfactory hip function at the minimum 5 years after the index revision surgery. Six of the 11 hips with preoperative pelvic discontinuity either failed or developed a radiolucency in zone 3 and are considered at risk for future revision. Pelvic discontinuity should prompt consideration of the addition of adjunctive fixation or the use of alternative techniques.
LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Abstract Objectives This study examined the influence of physical qualities on markers of fatigue and muscle damage following rugby league match-play. Design Between subjects design. Methods ...Twenty-one male youth rugby league players (age 19.2 ± 0.7 years; height 180.7 ± 5.6 cm; body mass 89.9 ± 10.0 kg) participated in the study. Yo-Yo intermittent recovery test (level 1), 3 repetition maximum back squat and bench press were assessed prior to 2 competitive fixtures. Neuromuscular fatigue (countermovement jump CMJ and plyometric push-up PP), and blood creatine kinase (CK) were assessed before and after match-play. During match-play, movements were recorded using microtechnology. Players were divided into high- and low-groups based on physical qualities. Results High Yo-Yo and squat performance resulted in greater loads during match-play ( p < 0.05). There were larger reductions in CMJ power in the low Yo-Yo group at both 24 (ES = −1.83), and 48 h post-match (ES = −1.33). Despite greater internal and external match loads, changes in CMJ power were similar between squat groups. There were larger increases in blood CK in the low Yo-Yo group at 24 (73% vs. 176%; ES = 1.50) and 48 h post-match (28% vs. 80%; ES = 1.22). Despite greater contact loads, the high squat group exhibited smaller changes in blood CK post-match (ES = 0.25–0.39). Conclusions Post-match fatigue is lower in players with well-developed high-intensity running ability, and lower body strength, despite these players having greater internal and external match loads.
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