MATLAB - Read from 2 SPI inputs synchronously I am using the MATLAB Arduino Support Package to create a setup where I can read force data from a load cell and positional data from an incremental encoder - then plot them on MATLAB. It must be done at the same time in order to produce a material stress-strain curve.

I am thinking of using the SPI Device functions to do this. 

Can the data from the load cell and encoder be read synchronously?
Yes and No.
 Synchronously in development slang means step-by-step execution. Asyncronously mean by some event.

Arduino has only one core. Even if you use interrupt, Arduino can only execute one command at once.

Best way for you I guess would be read both on Arduino and combine into single value to read at once. Just reading both with readDigitalPin  would give huge latency.