The polling rate in the provided firmware and Android app is 1Hz. This is programmed in the firmware, specifically in "HspBLE.cpp": (ticker.attach(this, &HspBLE::tickerHandler, 1);)
Currently, the polling rate applies to all the sensors. If you want to reconfigure the accelerometer independently from the rest, one option is to create a separate ticker, and tickerhandler function for the accelerometer.