Connection between the EMG detector sensor and an ESP32/Arduino UNO

I connected the EMG sensor to the ESP and read the analog signals from the sensor. However, the signal does not make sense, because there are hardly any deviations in the voltage when the muscle is tensed. Therefore my question: Do I need the Seeeduino V3.0 and the Grove - Base Shield to operate the sensor correctly? Does anyone have experience with connecting the sensor to an ESP32?

Here is the code I use for the Signal:

// EMG-Sensor is connected to GPIO 34 (Analog ADC1_CH6)
const int EMG_Pin = 34;

// variable for storing the EMG-Sensors value
double EMG_Signal = 0;

void setup() {
pinMode(34, INPUT);

void loop() {