EFFECT OF DIAPHRAGMATIC BREATHING EXERCISES ON HAMSTRING FLEXIBILITY AND STRETCH-RELATED DISCOMFORT IN AMATEUR ATHLETES: AN EXPERIMENTAL STUDY

Abstract

Background
Hamstring flexibility is an important component of efficient lower-limb movement and is frequently
limited in amateur athletes who participate in running, kicking, jumping, acceleration, deceleration,
and repeated changes of direction. Conventional flexibility programs primarily use stretching and
mobility exercises. The diaphragm, however, also contributes to trunk stabilization, intra-abdominal
pressure regulation, postural control, and autonomic modulation. These functions provide a clinical
rationale for examining whether diaphragmatic breathing can enhance the response to conventional
hamstring flexibility training.
Objective
To evaluate the effect of diaphragmatic breathing exercises, when added to traditional stretching and
flexibility exercises, on hamstring flexibility and stretching-related discomfort in amateur athletes.
Methods
An experimental comparative study was conducted on 60 amateur athletes aged 18–30 years.
Participants were equally divided into Group A (n=30) and Group B (n=30). Group A performed
diaphragmatic breathing exercises together with the same progressive traditional stretching and
flexibility program used in Group B, whereas Group B performed the flexibility program alone.
Hamstring flexibility was assessed using the Active Knee Extension (AKE) test for both limbs, and
discomfort during stretching was assessed using the Numeric Pain Rating Scale (NPRS). Paired t-
tests were used for within-group comparisons, independent t-tests for between-group comparisons,
chi-square analysis for categorical outcomes, and Pearson correlation for associations. Statistical
significance was set at p<0.05.
Results
Both groups demonstrated significant improvement following intervention. Average AKE increased
from 47.89 ± 5.43° to 59.68 ± 6.02° in Group A and from 45.97 ± 4.87° to 52.82 ± 5.39° in Group B.
Mean AKE gain was significantly greater in Group A (11.80 ± 2.28°) than Group B (6.86 ± 2.29°;
t=8.369, p<0.001; Cohen d=2.16). NPRS decreased from 6.29 ± 1.20 to 2.93 ± 1.29 in Group A and
from 6.38 ± 0.99 to 4.30 ± 0.98 in Group B. NPRS reduction was also greater in Group A (3.37 ±
0.69) than Group B (2.08 ± 0.54; t=8.045, p<0.001; Cohen d=2.08). Clinical improvement was
achieved by 96.7% of Group A compared with 26.7% of Group B.
Conclusion
Diaphragmatic breathing added to traditional stretching and flexibility exercises produced greater
improvement in hamstring flexibility and greater reduction in stretching-related discomfort than
traditional flexibility exercises alone. The findings support diaphragmatic breathing as a simple
adjunct to flexibility training in amateur athletes.