Hi! I’m a bit new with using arduino.
My project idea very short: Monitoring activity in a horse’ back legs during training.
I have an Arduino 101 (which I have used previously with the built-in IMU sensor and bluetooth).
Now I want to make a system with two MyoWare Musle Sensors. How/Can I connect these to the arduino 101?
Is it simply just a caple from each of the sensors to the arduino?
Hope somehow can help 
Yes it is that simple I believe.
According to the datasheet of your sensor, there is one output pin which should be connected to your Arduino.
It looks like your output from your sensor will output an analog signal which can be used to sense how your sensor is getting data.
Make the correct connections of your sensor in accordance with your data sheet and it all should be relatively straight forward.
Reference: https://cdn-shop.adafruit.com/product-f … 04-001.pdf