India, March 15 -- Former national coach and Dhronacharya awardee U. Vimal Kumar has expressed concerns over the recent underperformance of Indian shuttlers on the big stages. Indian badminton stars had a forgettable run in the Paris Olympics as they returned to the country medal-less. Lakshya Sen did give India some hope by reaching the semis in Paris, but he failed to get past Viktor Axlesen. In the recent All England Open quarterfinal, he suffered the same fate and lost to Chinese sixth seed Li Shifeng in 45 minutes in Birmingham. The Indian challenge ended in All England as the women's doubles pair of Treesa Jolly and Gayatri Gopichand also lost their quarters to Chinese second seeds Liu Shengshu and Tan Ning 14-21 10-21 in a match la...