Sampling rate question for datalogging

Hi, I'm wondering about the sampling frequency capabilities for the Arduino. I'm currently using an Adafruit datalogging Arduino shield, a robotshop strain gauge shield, and an Arduino uno. For some reason, I've only been able to record data at a frequency of ~50 Hz, which is a little low for the application I'm trying to use this set up for. Is there anyway to change this or bump up the sampling frequency or am I stuck with this number?

Reopening the file too often? Using the ADC? Heavy calculations when logging? How many data is converted to text per log?

am I stuck with this number?

Yes, until you post the code, and other required details. See “How to use this forum” post.