Introduction: Underweight (UW) individuals face lot of problems in increasing muscle size and also increasing body weight and fitness levels. Resistance training (RT) plays a very important role in increasing hypertrophy of the muscles one and all in general. (ACSM, 2009) stated that the resistance exercise for healthy adults provides program design recommendations for muscle hypertrophy [3]. The purpose of this study is to find out the influence of low, Medium and high intensity of (RT) on the muscular hypertrophy and selected health related fitness variables among the underweight males. Method: A group of (N=40) subjects was selected randomly to participate in this study. The age of the participants was in the range of 18-24 years, (RT) program was employed for 12 weeks, two days in a week, 45 minutes of training per session. The subjects were segregated into two groups namely Group-A (n=20, experimental group), Group –B (n=20 control group). The (RT) was employed on experimental group. Control group was not given any above mentioned special training program. The tests (pre and post) considered for this study was health related fitness variables are as follows; body composition, muscular strength, muscular endurance, Flexibility and cardio-vascular endurance. And test for muscular hypertrophy i.e. (neck, shoulders, chest, arms, waist, hips, thigh and calf; To compare the mean differences from pre to post test, mean, standard deviation, and t-test was computed by the help of statistica software. Results & Discussion: 12 weeks of training protocol had revealed significant performance from pre to posttest among the subjects with regard to the selected fitness variables and presented by percentages i.e. BMI (4.45%), bench press (35.12%), sit-ups test (22.34%), sit & reach test (26.83%), and 12 min run & walk test (26.94%). Furthermore the muscular hypertrophy was enhance among the underweight students i.e. Neck (2.61%), shoulder (2.95%), chest (6.75%), arms (10.43%), waist (8.23%), thighs (11.15%), calves (4.08%) ; and lastly hip circumference by (3.33%) had shown reduction in size from pre to post test. Conclusion: It is concluded that the influence of training had shown significant performance among the (UW) students with regard to the selected fitness test i.e. (BMI), bench press, sit-ups test, sit & reach test and 12 min run & walk test. Furthermore the selected muscular hypertrophy of the (UW) students i.e. Neck, shoulder, chest, arms, waist, thighs, calves circumference had shown increased in the muscular size and hip circumference had shown reduction in size from pre to post test.

中文翻译：

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耐力训练中低，中，高强度阻力训练对肌肉肥大及与健康相关的体能选择变量的影响

简介：体重不足（UW）的人在增加肌肉大小以及增加体重和健身水平方面面临许多问题。一般来说，阻力训练（RT）在增加肌肉肥大中起着非常重要的作用。（ACSM，2009）指出，针对健康成年人的抵抗运动为肌肉肥大提供了程序设计建议[3]。这项研究的目的是找出低，中，高强度（RT）对体重过轻的男性肌肉肥大和与健康相关的某些健身变量的影响。方法：随机选择一组（N = 40）受试者参加本研究。参加者的年龄在18-24岁之间，（RT）程序使用12周，一周两天，每节训练45分钟。将受试者分为两组，即A组（n = 20，实验组），B组–B（n = 20对照组）。（RT）用于实验组。对照组没有接受上述任何特殊培训。这项研究考虑的与健康相关的健康变量的测试（前后）如下；身体成分，肌肉力量，肌肉耐力，柔韧性和心血管耐力。并测试肌肉肥大，例如（脖子，肩膀，胸部，手臂，腰部，臀部，大腿和小腿）；为了比较前后测试的平均值差异，借助统计学方法计算平均值，标准差和t检验结果与讨论：12周的训练规程表明，从测试前到测试后，受试者在选定的健身变量方面有显着表现，并以百分比表示，例如BMI（4.45％），卧推（35.12％），仰卧起坐测试（22.34％），坐姿测试（26.83％）和12分钟跑步测试（26.94％）。此外，体重过轻的学生的肌肉肥大得到增强，即颈部（2.61％），肩膀（2.95％），胸部（6.75％），手臂（10.43％），腰部（8.23％），大腿（11.15％），小腿（4.08） ％）; 最后，髋周长降低了（3.33％）。结论：结论是，就选择的体能测验（BMI），卧推，仰卧起坐测验，坐直及伸直测验和12分钟跑步及步行测验而言，培训的影响在（UW）学生中显示出显着的表现测试。