A system for monitoring performance of a user, the system comprising: one or more pole for skiing or Nordic walking, the at least one pole comprising a grip , a pole part , at least one force sensor , and an adapter, wherein the adapter is operatively connected to the at least one force sensor and enables the pole part to be attached to the grip 480; at least one processor; at least one cardiac activity sensor configured to measure cardiac activity data of the user; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the system to perform operations comprising: obtaining force data measured by the at least one force sensor coupled with the one or more poles and velocity data measured by at least one sensor for measuring velocity of the user, the velocity data indicating velocity of the user; determining poling power based on the force data and the velocity data; and outputting a poling power indicator based on the determined poling power; obtaining the cardiac activity data of the user measured by the at least one cardiac activity sensor; determining heart rate of the user based on the cardiac activity data; determining performance efficiency of the user based on the determined poling power and the determined heart rate; and outputting an efficiency indicator based on the determined performance efficiency. one or more pole for skiing or Nordic walking, the at least one pole comprising a grip , a pole part , at least one force sensor , and an adapter, wherein the adapter is operatively connected to the at least one force sensor and enables the pole part to be attached to the grip 480; at least one processor; at least one cardiac activity sensor configured to measure cardiac activity data of the user; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the system to perform operations comprising: obtaining force data measured by the at least one force sensor coupled with the one or more poles and velocity data measured by at least one sensor for measuring velocity of the user, the velocity data indicating velocity of the user; determining poling power based on the force data and the velocity data; and outputting a poling power indicator based on the determined poling power; obtaining the cardiac activity data of the user measured by the at least one cardiac activity sensor; determining heart rate of the user based on the cardiac activity data; determining performance efficiency of the user based on the determined poling power and the determined heart rate; and outputting an efficiency indicator based on the determined performance efficiency. obtaining force data measured by the at least one force sensor coupled with the one or more poles and velocity data measured by at least one sensor for measuring velocity of the user, the velocity data indicating velocity of the user; determining poling power based on the force data and the velocity data; and outputting a poling power indicator based on the determined poling power; obtaining the cardiac activity data of the user measured by the at least one cardiac activity sensor; determining heart rate of the user based on the cardiac activity data; determining performance efficiency of the user based on the determined poling power and the determined heart rate; and outputting an efficiency indicator based on the determined performance efficiency. <EOS>