Objective To improve the underwater technique during the start phase of breaststroke swimmers through swimming flume training and assess its effectiveness in enhancing competitive performance.Methods The participants were 14 male swimmers in the short-distance Level 4 category from the Shanghai Swimming Team,and they were randomly divided into the experimental group(n=7)and control group(n=7).The experimental group underwent swimming flume start training,while the control group underwent regular pool start training,and both groups received the training twice a week for 16 weeks.Before and after the 16-week training,a 15-m breaststroke start test was conducted.Repeated measures analysis of variance and paired t-tests were used to compare the changes in kinematic parameters(time,speed,and entry angle)between and within groups.Results After 16 weeks of specialized training,the 15-m performance at the start for the experimental group and control group(F(1,12)=6.52,P＜0.05,η2=0.39)showed an interaction,with the experimental group performing better after training compared to the control group before training(P＜0.05).In the experimental group,the duration of the pull-out phase(F(1,12)=10.28,P＜0.01,η2=0.46)and the second sliding phase(F(1,12)=4.81,P＜0.05,η2=0.22)was improved;the distance of the pull-out phase(F(1,12)=4.71,P＜0.05,η2=0.21)and the second sliding phase(F(1,12)=4.90,P＜0.05,η2=0.21)was improved;the speed of the pull-out phase(F(1,12)=4.77,P＜0.05,72=0.20)was significantl improved.The within-group statistics showed that the experimental group significantly improved their exit speed(P＜0.05).The hand entry angle was optimized(P＜0.05),while changes in other joint angles were not significant.Conclusions Swimming flume training reduced the time spent in the pull-out and second gliding phases during the breaststroke start,effectively preventing the speed loss during underwater gliding.This provides an experimental evidence for enhancing start performance and optimizing training method for breaststroke swimmers.

Objective To improve the underwater technique during the start phase of breaststroke swimmers through swimming flume training and assess its effectiveness in enhancing competitive performance.Methods The participants were 14 male swimmers in the short-distance Level 4 category from the Shanghai Swimming Team,and they were randomly divided into the experimental group(n=7)and control group(n=7).The experimental group underwent swimming flume start training,while the control group underwent regular pool start training,and both groups received the training twice a week for 16 weeks.Before and after the 16-week training,a 15-m breaststroke start test was conducted.Repeated measures analysis of variance and paired t-tests were used to compare the changes in kinematic parameters(time,speed,and entry angle)between and within groups.Results After 16 weeks of specialized training,the 15-m performance at the start for the experimental group and control group(F(1,12)=6.52,P＜0.05,η2=0.39)showed an interaction,with the experimental group performing better after training compared to the control group before training(P＜0.05).In the experimental group,the duration of the pull-out phase(F(1,12)=10.28,P＜0.01,η2=0.46)and the second sliding phase(F(1,12)=4.81,P＜0.05,η2=0.22)was improved;the distance of the pull-out phase(F(1,12)=4.71,P＜0.05,η2=0.21)and the second sliding phase(F(1,12)=4.90,P＜0.05,η2=0.21)was improved;the speed of the pull-out phase(F(1,12)=4.77,P＜0.05,72=0.20)was significantl improved.The within-group statistics showed that the experimental group significantly improved their exit speed(P＜0.05).The hand entry angle was optimized(P＜0.05),while changes in other joint angles were not significant.Conclusions Swimming flume training reduced the time spent in the pull-out and second gliding phases during the breaststroke start,effectively preventing the speed loss during underwater gliding.This provides an experimental evidence for enhancing start performance and optimizing training method for breaststroke swimmers.

Objective:To analyze the gene mutation types and clinical hematological phenotypes of abnormal hemoglobinopathy in couples of childbearing age in Nanhai District, Foshan.Methods:The hemoglobinopathy gene sequencing, blood routine testing, and hemoglobin capillary electrophoresis results of 24 748 samples from prenatal and premarital examinations at Nanhai Maternity and Child Healthcare Hospital of Foshan from August 2017 to November 2023 were retrospectively analyzed.Results:Totally 41 abnormal hemoglobinopathy genotypes were detected in 294 cases, the detection rate was 1.19% (294/24 748). There were 24 genotypes involved in α globin structural variation, with 172 cases. There were 13 genetypes involved in β globin structural variation, with 118 cases. There were 4 genotypes involved in α + β globin structural variation, with 4 cases. Among them, Hb New York (82 cases), Hb Hekinan Ⅱ (76 cases), Hb Owari (29 cases), and Hb Q-Thailand (27 cases) were the most common genetypes. Among 274 cases of abnormal hemoglobinopathy gene carriers, 89 cases were positive in blood routine phenotype, the detection rate was 32.48%, including 81 cases with abnormal mean corpuscular volume (MCV) and 71 cases with abnormal mean corpuscular hemoglobin (MCH). There were 166 cases with positive phenotype in hemoglobin capillary electrophoresis, the detection rate was 60.58%, among them 81 cases with abnormal HbA 2 and 133 cases with abnormal hemoglobin band. Most of the abnormal hemoglobinopathy gene carriers without combined α or β-thalassemia had no clinical symptoms or only mild clinical symptoms, and a small number had positive hematological phenotypes. Conclusions:The incidence of abnormal hemoglobinopathy is relatively high among couples of childbearing age in Nanhai District, Foshan, and the main variation is α globin structure variation. Some genetypes are positive for hemoglobin capillary electrophoresis, and a few gene types show anemia symptoms.