Investigators will conduct a randomized controlled trial to examine whether
moderate-intensity combined aerobic and resistance exercise can improve semen quality. A
total of 60 participants will be recruited from one university. Inclusion criteria were
college students aged 18 to 24 who signed informed consent form, good health with no
eating disorders, mental health disorders, chronic diseases, serious systemic illnesses,
genitourinary diseases or infections, and were assessed as having "low" physical activity
on the self-reported International Physical Activity Questionnaire (IPAQ), with sperm
progressive motility of less than 32%, at least two evaluations at three-month intervals.
Exclusion criteria include smoking, alcohol dependence, and use of drugs that affect
sperm production function such as hormones and antibiotics within the past 3 months, and
history of reproductive system surgery (e.g., cryptorchidism, postoperative varicocele).
After stratification by BMI, participants were assigned 1:1 to the intervention and
control groups.
The intervention group will receive 12 weeks of moderate-intensity combined aerobic and
resistance exercise training for 90 minutes three times per week on non-consecutive days.
Aerobic exercise is carried out in the form of running and skipping rope, and resistance
exercise involves different muscle groups in the upper and lower limbs of the body. All
training sessions will be conducted daily at the same time (17:00-18:30) under the
guidance of a professional physical education teacher and two trained postgraduate
medical students. Before the start of the exercise intervention, participants in the
intervention group will be tested to determine the maximum heart rate and the repetitions
maximum (RM) of resistance training. Training sessions begin with a 15-minute warm-up
period that includes jogging and dynamic muscle stretching. This is followed by 25
minutes of running/jumping rope on the playground. Each intervention participant will
wear a heart rate armband (Polar OH1, Finland) for real-time heart rate detection to
maintain achievement of a predetermined target heart rate and training intensity. Target
heart rate of moderate-intensity = maximum heart rate x 64%~76%. Then, after 10 minutes
of rest adjustment and preparation, a 25-minute resistance training session will be
performed, including all major muscle groups. Exercises for upper body muscles such as
push-ups, pull-ups, and bench press; Lower body exercises included leg press, squats, and
supine leg raises; and exercises for core muscle groups such as planks, sit-ups, and hip
bridge. Resistance training will start at 50% of 1RM and increases intensity by 10% after
every three sessions, with two sets of repetitions and 60-90 seconds of rest between
sets. By the third week, it will reach 70% of 1RM, and repeat 3 sets at 70% of 1RM
starting at week 4. After the end of week 6, re-evaluate the RM every 3 weeks and repeat
3 sets at 70% of the new 1RM (i.e., starting from Week 7 and Week 10), maintaining a
60-90 second rest between each sets. During resistance training the heart rate is
likewise detected to be in the target heart rate. The Borg rating of perceived exercise
(RPE) is combined with target heart rate for monitoring exercise intensity during
exercise implementation. RPE will be applied at the end of warm-up, aerobic exercise, and
resistance exercise to assess the subjective perception of participants during exercise.
RPE scores of 12-13 indicate moderate intensity. After resistance training, investigators
will perform a 15-minute relaxation session that includes slow walking and static muscle
stretching.
The control group did not receive exercise intervention and maintained their original
physical activity habits. All participants were required to maintain normal dietary
habits during the study period. The primary outcome of this study is to compare the
change of sperm progressive motility between intervention and control groups from pre- to
post-intervention at 12 weeks.