Objective:To analyze the trabecular bone score (TBS) and its association with muscle health in the postmenopausal population.Methods:It was a cross-sectional study. A total of 214 postmenopausal individuals who underwent dual-energy X-ray absorptiometry testing at the Beijing Research Institute of Sports Science between January and December 2023 were consecutively included. The participants were divided into two groups based on the presence or absence of osteoporosis (OP): 62 cases in the OP group and 152 cases in the non-OP group. All subjects completed body composition assessments and scans of bilateral hip and lumbar spine bone mineral density (BMD)(All the BMD in this study were areal BMD). Demographic data, including age, age at menarche, age at menopause, and fracture history, were also collected. TBS was calculated using the TBS iNsight software. Muscle health indicators included upper limb, lower limb, trunk, and total muscle mass, lean body mass, appendicular skeletal muscle mass index (ASMI), and grip strength. The Pearson correlation analysis was used to determine the relationship between TBS and muscle health indicators, as well as between TBS and the BMD of lumbar spine (L 1-4). Further, multiple linear regression analysis was conducted to explore the independent association between TBS and muscle health indicators. Results:TBS, lean body mass, ASMI, grip strength, and muscle mass of the upper limb, lower limb, trunk, whole body in the OP group were all lower than those in the non-OP group [(1.27±0.07) vs (1.35±0.07) score, (36.64±3.45) vs (39.14±3.62) kg, (6.16±0.56) vs (6.44±0.63) kg/m2, (23.87±3.31) vs (25.34±4.33) kg, (3.54±0.47) vs (3.78±0.47) kg, (11.70±1.33) vs (12.68±1.49) kg, (16.57±1.68) vs (17.50±1.69) kg, and (34.91±3.33) vs (37.13±3.47) kg] (all P<0.05). Pearson analysis showed that TBS was positively correlated with lean body mass, ASMI, grip strength, and muscle mass of the upper limb, lower limb, whole body (all P<0.05). TBS was negatively correlated with age ( P<0.01). TBS was positively correlated with the BMD of lumbar spine (L 1-4) ( r=0.660, P<0.01). Multiple regression analysis demonstrated that ASMI was positively correlated with TBS ( β=0.284, P<0.01). Conclusion:In the postmenopausal population, individuals with OP have lower TBS. Furthermore, TBS is closely associated with muscle health.

Objective:To clarify the safety, repair rate, durability, and risk factors for recurrent mitral regurgitation(MR) in patients with Barlow disease(BD) who total thoracoscopic minimally invasive mitral valvuloplasty(TMVP).Methods:Clinical data, mid-term and long-term outcomes of BD patients who underwent TMVP at Guangdong Provincial People's Hospital from January 2009 to June 2022 were retrospectively analyzed. Patients were divided into a group with no MR recurrence(group A) and a group with MR recurrence(group B) according to whether recurrent MR appeared in the postoperative period, and the data of the two groups of patients were compared with each other for the risk factor analysis.Results:The repair rate of TMVP was 98.4%, and no patient died perioperatively. The median follow-up time was 3.1(1.7, 5.2) years, the follow-up rate was 95.8%, and there was no patient died. As of March 2023, 112 patients developed no recurrent MR(group A), 11 patients developed recurrent MR(group B), and 2 patients in group B underwent repeated mitral valve surgery. The left atrial diameter(LAD) and left ventricular end-systolic diameter(LVESD) were higher in group B than in group A patients[LAD: (50.9±7.7)mm vs.(43.7±8.7)mm, P=0.009; LVESD: (37.1±5.5)mm vs.(33.2±4.7)mm, P=0.011], and the percentage of tendon cord rupture was higher in group B than in group A( P=0.022), while the rest of the baseline data were not statistically significant. There was no statistically significant difference between two groups in terms of the use of different surgical techniques, aortic cross-clamp time, cardiopulmonary bypass time, and operative time. Postoperative LAD, postoperative LVESD, and postoperative left ventricular end-diastolic diameter of group B patients were higher than those of group A( P<0.05). There was no statistically significant difference in perioperative and long-term complication rates between the two groups. Multifactorial Cox regression analysis revealed that advanced age( HR=1.049, 95% CI: 0.997-1.103, P=0.066) and large preoperative LVESD( HR=1.168, 95% CI: 1.053-1.295, P=0.003) were the risk factors for postoperative recurrence MR. Conclusion:Total thoracoscopic minimally invasive BD repair is safe, which has a high success rate and good long-term results. Advanced age and large preoperative LVESD are risk factors for recurrent MR in the long term.

Objective:To compare the clinical effects of restrictive transfusion strategy and liberal transfusion strategy for cardiac valve surgery.Methods:This study employed a prospective, randomized controlled superiority design, enrolling 439 patients undergoing non-emergency cardiac valve surgery with cardiopulmonary bypass at Department of Cardiovascular Surgery, Guangdong Provincial People′s Hospital, Southern Medical University from June 2023 to October 2024 who met the inclusion and exclusion criteria. While all the patients appeared hematocrit (Hct)≤24% or hemoglobin (Hb)≤80 g/L during the cardiopulmonary bypass. A simple random design was adopted to generate a random sequence and participants were randomized into a restrictive transfusion group (restrictive criteria: Hct≤18% or Hb≤60 g/L during cardiopulmonary bypass, and Hct≤21% or Hb≤70 g/L postoperatively) or a liberal transfusion group (liberal criteria: Hct≤24% or Hb≤80 g/L during cardiopulmonary bypass and Hct≤30% or Hb≤100 g/L postoperatively). If Hb or Hct fell below the respective thresholds, 2 units of red blood cells were transfused, followed by re-evaluation. If levels remained below the threshold, an additional 2 units were transfused until the criteria were met. The primary outcome was a composite of postoperative 3-month mortality, infection, ischemic events, and new-onset renal failure requiring dialysis. Secondary outcomes included blood product utilization, length of stay in the ICU and so on. Intergroup comparisons were performed using independent sample t-test, Mann-Whitney U test, χ2 test, or Fisher′s exact test, and analyses were conducted using a binary multivariable Logistic regression model. Results:A total of 439 patients were included in this study. The restrictive roup included 221 patients, including 75 males and 146 females, aged ( M(IQR)) 57.0 (14.0) years (range: 21 to 76 years). The liberal group included 218 patients, including 67 males and 151 females, aged 56.0 (20.0) years (range: 19 to 74 years). No statistically significant difference was observed in the incidence of primary outcome (restrictive group: 10.9%(24/221) vs. liberal group: 9.6%(21/218), χ2=0.180, P>0.05), 2 patints in the restrictive group died and 3 patints in liberal group died ( P=0.684). The transfusion rate was significantly lower in the restrictive group(19.0%(42/221) vs. 100%(218/218), P<0.01), with no significant differences in other secondary outcomes (all P>0.05). Subgroup analysis revealed an interaction between sex and transfusion strategy ( P=0.023), suggesting that using liberal transfusion strategy in male patients might increase the risk of the primary outcome. Conclusion:The mid-term results do not show that the restrictive transfusion strategy is superior to the liberal transfusion strategy in reducing the incidence of postoperative outcome events in patients undergoing cardiac valve surgery.

Objective To evaluate the effectiveness of low-volume high-intensity interval training(LV-HIIT)protocols defined by the W'Balance(W'BAL)model in achieving maximal activation of both anaerobic and aerobic energy systems.Methods Twenty-eight national-level athletes(age:20±1 years old;height:174±9 cm;weight:65.1±9.4 kg)completed an incremental exercise test,followed by six supra-critical power(supra-CP)and five sub-CP constant-load tests to determine VO2max,maximal accumulated oxygen deficit(MAOD),critical power(CP),and W prime(W').They then performed three randomly ordered LV-HIIT protocols(each of 4-minute total duration),with a 10-second inter-val for passive recovery between bouts.The protocols consisted of 10s(HIIT10/10),20s(HIIT20/10),and 30 s(HIIT30/10).Exercise intensities were individually prescribed using the W'BAL model.Accu-mulated oxygen deficit(AOD)and net AOD(NAOD)were calculated for each protocol.Results Final 10-s oxygen uptake(VO2)reached 77％,88％,and 89％of VO2max in HIIT10/10,HIIT20/10,and HIIT30/10,respectively(P<0.05).VO2 in HIIT10/10 was significantly lower than in HIIT20/10 and HIIT30/10(P<0.05),with no significant difference between the latter two(P>0.05).AOD did not differ significantly from MAOD among the three protocols(P>0.05),whereas NAOD was significantly lower than MAOD in all cases(P<0.05).Additionally,NAOD in HIIT10/10 was significantly lower than in HIIT20/10 and HI-IT30/10(P<0.05),with no significant difference between the latter two(P>0.05).Conclusion The HIIT20/10 and HIIT30/10 intensity established by the W'BAL model can substantially elicit maximal activation of both anaerobic and aerobic energy systems.While the W'BAL model demonstrates potential for set-ting exercise intensities in LV-HIIT,future studies are necessary to develop specific W'recovery rate models for targeted populations and to refine CP models that are better suited for intermittent exercises.

Objective To compare the effectiveness of the heart rate variability threshold(HRVT),muscle oxygenation threshold(MOT),and their combined threshold(COMT)in predicting the ventila-tory threshold(VT)and lactate threshold(LT).Methods Twenty male athletes at or above the nation-al level were recruited to perform an incremental exercise test to determine VT and LT,during which gas exchange,muscle oxygenation,and heart rate variability were collected.The HRVT,MOT,and COMT methods were then applied,and their predictive validity was evaluated by comparing the correla-tions and agreements between heart rate(HR)and power output(PO)at VT and LT.Results For HR,VT1 showed strong correlation and agreement with MOT1(r=0.958,ICC=0.944)and COMT1(r=0.957,ICC=0.951),with COMT1 having the smallest mean bias(1.4 bpm)and the narrowest limits of agreement(LOA)(-5.4 to 8.2 bpm).Moreover,VT2 demonstrated the highest correlation and agree-ment with COMT2(r=0.985,ICC=0.982),with a mean bias of-0.7 bpm and LOA of-5.0 to 3.7 bpm.Meanwhile,LT showed high correlation and good agreement with COMT2(r=0.884,ICC=0.754)and MOT2(r=0.886,ICC=0.738),with mean biases of-6.8 bpm and-7.3 bpm,and LOA of-17.5 to 3.8 bpm and-17.9 to 3.2 bpm,respectively.For PO,VT1 had the best correlation and agreement with MOT1(r=0.836,ICC=0.808),with a mean bias of-0.2 W and LOA of-11.7 to 11.3 W.VT2 performed best correlation and agreement with COMT2(r=0.910,ICC=0.900),with a mean bias of 2.3 W and LOA of-8.9 to 13.5 W.In LT prediction,MOT2(r=0.736,ICC=0.692)outperformed COMT2(r=0.635,ICC=0.618),with mean biases of-2.6 W and 0.2 W,and LOA of-26.0 to 20.7 W and-26.6 to 27.1 W,respectively.Conclusion All three indicators—HRVT,MOT,and COMT—demonstrates high validity in predicting VT and LT.MOT1 performs best for predicting PO at VT1,while COMT2 shows the highest consistency for predicting both HR and PO at VT2.Howev-er,for LT prediction,MOT2 is more advantageous for predicting PO,whereas COMT2 is more accu-rate for predicting HR.Therefore,method selection should be tailored to the specific threshold type and measurement target.

Objective To explore the effect of hypoxic exercise on Irisin secretion of obese rats with a palmitic acid-induced lipid accumulation in L6 myotubes and a high-fat diet-induced model.Methods L6 myotubes were treated with 750 μmol/L palmitic acid to induce lipid accumulation and subsequently divided into four groups of normoxia(N),exercise(E),hypoxia(H),and hypoxic exer-cise(HE).Hypoxic conditions(1%O2)were used to simulate a low-oxygen environment,while AICAR stimulation was applied to the E and HE groups to mimic exercise.Eighty 3-week-old Sprague-Dawley rats were fed a high-fat diet for 16 weeks to establish an obesity model.Fifty obese rats that met the criteria were then selected and randomly assigned according to their body weight into five groups of normoxia-sedentary(NC),normoxia-exercise(NE),hypoxia-sedentary(HC),high-liv-ing high-training(HH),and low-living high-training(LH),each of 10.The hypoxic environment was set at 13.6%O2(simulating 3,500 m altitude).Then the NE,HH and LH groups performed daily one-hour treadmill training(NE:20 m/min;HH and LH:16 m/min),5 days/week for 4 weeks.After the intervention,the body composition was measured using dual-energy X-ray absorptiometry(DEXA),while Irisin concentrations in cell culture media and rat serum were determined by using the enzyme-linked immunosorbent assay.Moreover,fibronectin type Ⅲ domain-containing 5(FNDC5)mRNA expression in L6 cells and rat skeletal muscle was measured by quantitative polymerase chain reaction(qPCR),while FNDC5 and silent information regulator 1-peroxisome proliferators-activated re-ceptor γ coactivator lalpha(SIRT1-PGC-1α)pathway proteins were analyzed using Western blotting.Results(1)Cell experiments:①Compared with the N group,there were significantly higher Irisin lev-els in the culture medium of the E,H,and HE groups(P<0.01,P<0.05),as well as elevated FNDC5 mRNA and protein expression in the E and HE groups(P<0.05,P<0.01).Moreover,the Iri-sin concentration and FNDC5 protein levels of group HE were significantly higher than group E(P<0.05).②Compared with group N,significantly increased SIRT1 and PGC-1α protein expression was observed in groups E and HE(P<0.05,P<0.01).(2)Animal experiments:①Compared with the NC group,body weight and fat mass were significantly lower in the NE,LH,and HH groups(P<0.01),with further reductions observed in the HH group compared with the NE group(P<0.05).② Com-pared with group NC,groups NE,LH,and HH exhibited higher serum Irisin levels and increased FNDC5 mRNA and protein expression in skeletal muscle(P<0.05,P<0.01).Furthermore,FNDC5 pro-tein expression of the HH group was significantly higher than the NE group(P<0.05).③ Compared with the NC group,SIRT1 and PGC-1α protein levels were significantly upregulated in the NE,LH,and HH groups(P<0.05,P<0.01).Conclusion Hypoxic exercise effectively alleviates obesity,reduces body weight and fat accumulation in high-fat diet-induced obese rats,and enhances FNDC5 expres-sion and Irisin secretion,which may be mediated through activation of the SIRT1-PGC-1α signaling pathway.Moreover,among the different hypoxic exercise modalities,the"high-living high-training"protocol appears to have greater benefits in promoting FNDC5/Irisin expression and facilitating weight and fat reduction in obese rats.

Objective To compare the effectiveness of the heart rate variability threshold(HRVT),muscle oxygenation threshold(MOT),and their combined threshold(COMT)in predicting the ventila-tory threshold(VT)and lactate threshold(LT).Methods Twenty male athletes at or above the nation-al level were recruited to perform an incremental exercise test to determine VT and LT,during which gas exchange,muscle oxygenation,and heart rate variability were collected.The HRVT,MOT,and COMT methods were then applied,and their predictive validity was evaluated by comparing the correla-tions and agreements between heart rate(HR)and power output(PO)at VT and LT.Results For HR,VT1 showed strong correlation and agreement with MOT1(r=0.958,ICC=0.944)and COMT1(r=0.957,ICC=0.951),with COMT1 having the smallest mean bias(1.4 bpm)and the narrowest limits of agreement(LOA)(-5.4 to 8.2 bpm).Moreover,VT2 demonstrated the highest correlation and agree-ment with COMT2(r=0.985,ICC=0.982),with a mean bias of-0.7 bpm and LOA of-5.0 to 3.7 bpm.Meanwhile,LT showed high correlation and good agreement with COMT2(r=0.884,ICC=0.754)and MOT2(r=0.886,ICC=0.738),with mean biases of-6.8 bpm and-7.3 bpm,and LOA of-17.5 to 3.8 bpm and-17.9 to 3.2 bpm,respectively.For PO,VT1 had the best correlation and agreement with MOT1(r=0.836,ICC=0.808),with a mean bias of-0.2 W and LOA of-11.7 to 11.3 W.VT2 performed best correlation and agreement with COMT2(r=0.910,ICC=0.900),with a mean bias of 2.3 W and LOA of-8.9 to 13.5 W.In LT prediction,MOT2(r=0.736,ICC=0.692)outperformed COMT2(r=0.635,ICC=0.618),with mean biases of-2.6 W and 0.2 W,and LOA of-26.0 to 20.7 W and-26.6 to 27.1 W,respectively.Conclusion All three indicators—HRVT,MOT,and COMT—demonstrates high validity in predicting VT and LT.MOT1 performs best for predicting PO at VT1,while COMT2 shows the highest consistency for predicting both HR and PO at VT2.Howev-er,for LT prediction,MOT2 is more advantageous for predicting PO,whereas COMT2 is more accu-rate for predicting HR.Therefore,method selection should be tailored to the specific threshold type and measurement target.

Objective To explore the effect of hypoxic exercise on Irisin secretion of obese rats with a palmitic acid-induced lipid accumulation in L6 myotubes and a high-fat diet-induced model.Methods L6 myotubes were treated with 750 μmol/L palmitic acid to induce lipid accumulation and subsequently divided into four groups of normoxia(N),exercise(E),hypoxia(H),and hypoxic exer-cise(HE).Hypoxic conditions(1%O2)were used to simulate a low-oxygen environment,while AICAR stimulation was applied to the E and HE groups to mimic exercise.Eighty 3-week-old Sprague-Dawley rats were fed a high-fat diet for 16 weeks to establish an obesity model.Fifty obese rats that met the criteria were then selected and randomly assigned according to their body weight into five groups of normoxia-sedentary(NC),normoxia-exercise(NE),hypoxia-sedentary(HC),high-liv-ing high-training(HH),and low-living high-training(LH),each of 10.The hypoxic environment was set at 13.6%O2(simulating 3,500 m altitude).Then the NE,HH and LH groups performed daily one-hour treadmill training(NE:20 m/min;HH and LH:16 m/min),5 days/week for 4 weeks.After the intervention,the body composition was measured using dual-energy X-ray absorptiometry(DEXA),while Irisin concentrations in cell culture media and rat serum were determined by using the enzyme-linked immunosorbent assay.Moreover,fibronectin type Ⅲ domain-containing 5(FNDC5)mRNA expression in L6 cells and rat skeletal muscle was measured by quantitative polymerase chain reaction(qPCR),while FNDC5 and silent information regulator 1-peroxisome proliferators-activated re-ceptor γ coactivator lalpha(SIRT1-PGC-1α)pathway proteins were analyzed using Western blotting.Results(1)Cell experiments:①Compared with the N group,there were significantly higher Irisin lev-els in the culture medium of the E,H,and HE groups(P<0.01,P<0.05),as well as elevated FNDC5 mRNA and protein expression in the E and HE groups(P<0.05,P<0.01).Moreover,the Iri-sin concentration and FNDC5 protein levels of group HE were significantly higher than group E(P<0.05).②Compared with group N,significantly increased SIRT1 and PGC-1α protein expression was observed in groups E and HE(P<0.05,P<0.01).(2)Animal experiments:①Compared with the NC group,body weight and fat mass were significantly lower in the NE,LH,and HH groups(P<0.01),with further reductions observed in the HH group compared with the NE group(P<0.05).② Com-pared with group NC,groups NE,LH,and HH exhibited higher serum Irisin levels and increased FNDC5 mRNA and protein expression in skeletal muscle(P<0.05,P<0.01).Furthermore,FNDC5 pro-tein expression of the HH group was significantly higher than the NE group(P<0.05).③ Compared with the NC group,SIRT1 and PGC-1α protein levels were significantly upregulated in the NE,LH,and HH groups(P<0.05,P<0.01).Conclusion Hypoxic exercise effectively alleviates obesity,reduces body weight and fat accumulation in high-fat diet-induced obese rats,and enhances FNDC5 expres-sion and Irisin secretion,which may be mediated through activation of the SIRT1-PGC-1α signaling pathway.Moreover,among the different hypoxic exercise modalities,the"high-living high-training"protocol appears to have greater benefits in promoting FNDC5/Irisin expression and facilitating weight and fat reduction in obese rats.

Objective To evaluate the effectiveness of low-volume high-intensity interval training(LV-HIIT)protocols defined by the W'Balance(W'BAL)model in achieving maximal activation of both anaerobic and aerobic energy systems.Methods Twenty-eight national-level athletes(age:20±1 years old;height:174±9 cm;weight:65.1±9.4 kg)completed an incremental exercise test,followed by six supra-critical power(supra-CP)and five sub-CP constant-load tests to determine VO2max,maximal accumulated oxygen deficit(MAOD),critical power(CP),and W prime(W').They then performed three randomly ordered LV-HIIT protocols(each of 4-minute total duration),with a 10-second inter-val for passive recovery between bouts.The protocols consisted of 10s(HIIT10/10),20s(HIIT20/10),and 30 s(HIIT30/10).Exercise intensities were individually prescribed using the W'BAL model.Accu-mulated oxygen deficit(AOD)and net AOD(NAOD)were calculated for each protocol.Results Final 10-s oxygen uptake(VO2)reached 77％,88％,and 89％of VO2max in HIIT10/10,HIIT20/10,and HIIT30/10,respectively(P<0.05).VO2 in HIIT10/10 was significantly lower than in HIIT20/10 and HIIT30/10(P<0.05),with no significant difference between the latter two(P>0.05).AOD did not differ significantly from MAOD among the three protocols(P>0.05),whereas NAOD was significantly lower than MAOD in all cases(P<0.05).Additionally,NAOD in HIIT10/10 was significantly lower than in HIIT20/10 and HI-IT30/10(P<0.05),with no significant difference between the latter two(P>0.05).Conclusion The HIIT20/10 and HIIT30/10 intensity established by the W'BAL model can substantially elicit maximal activation of both anaerobic and aerobic energy systems.While the W'BAL model demonstrates potential for set-ting exercise intensities in LV-HIIT,future studies are necessary to develop specific W'recovery rate models for targeted populations and to refine CP models that are better suited for intermittent exercises.

Objective:To analyze the trabecular bone score (TBS) and its association with muscle health in the postmenopausal population.Methods:It was a cross-sectional study. A total of 214 postmenopausal individuals who underwent dual-energy X-ray absorptiometry testing at the Beijing Research Institute of Sports Science between January and December 2023 were consecutively included. The participants were divided into two groups based on the presence or absence of osteoporosis (OP): 62 cases in the OP group and 152 cases in the non-OP group. All subjects completed body composition assessments and scans of bilateral hip and lumbar spine bone mineral density (BMD)(All the BMD in this study were areal BMD). Demographic data, including age, age at menarche, age at menopause, and fracture history, were also collected. TBS was calculated using the TBS iNsight software. Muscle health indicators included upper limb, lower limb, trunk, and total muscle mass, lean body mass, appendicular skeletal muscle mass index (ASMI), and grip strength. The Pearson correlation analysis was used to determine the relationship between TBS and muscle health indicators, as well as between TBS and the BMD of lumbar spine (L 1-4). Further, multiple linear regression analysis was conducted to explore the independent association between TBS and muscle health indicators. Results:TBS, lean body mass, ASMI, grip strength, and muscle mass of the upper limb, lower limb, trunk, whole body in the OP group were all lower than those in the non-OP group [(1.27±0.07) vs (1.35±0.07) score, (36.64±3.45) vs (39.14±3.62) kg, (6.16±0.56) vs (6.44±0.63) kg/m2, (23.87±3.31) vs (25.34±4.33) kg, (3.54±0.47) vs (3.78±0.47) kg, (11.70±1.33) vs (12.68±1.49) kg, (16.57±1.68) vs (17.50±1.69) kg, and (34.91±3.33) vs (37.13±3.47) kg] (all P<0.05). Pearson analysis showed that TBS was positively correlated with lean body mass, ASMI, grip strength, and muscle mass of the upper limb, lower limb, whole body (all P<0.05). TBS was negatively correlated with age ( P<0.01). TBS was positively correlated with the BMD of lumbar spine (L 1-4) ( r=0.660, P<0.01). Multiple regression analysis demonstrated that ASMI was positively correlated with TBS ( β=0.284, P<0.01). Conclusion:In the postmenopausal population, individuals with OP have lower TBS. Furthermore, TBS is closely associated with muscle health.