How to specify the quickest movement a human can do based on MTM standards?
I don't know about any MTM standards or benchmarks, but motor response latencies have been assessed in many studies. Importantly, auditory response latencies are smallest, then tactile followed by visual response times. This, because the auditory system is swift, while the visual system is sluggish by comparison (source: Packman &amp; Packman).

For example, Jain et al. (2015) report a mean visual response latency of 247 ms and an auditory response latency of 228 ms. Another study reports approximately 144 and 133 ms, respectively. The lower values are probably because the authors chose the lowest reading as their final measurement Gavkare et al, 2013). Other technical differences may also have yielded deviations. Importantly, stimulus intensity affects reaction time (e.g., louder auditory stimuli decrease reaction time) and other stimulus parameters do so as well (source: Packman &amp; Packman). Importantly, age is positively correlated with reaction time (Ng &amp; Chan, 2012).     

A large data set where the authors stratified their subject pool in age groups as well as other parameters can be found in Ng &amp; Chan, 2012. 

References
- Gavkare et al,, Indian Medical Gazette, June 2013
- Jain et al., Int J Appl Basic Med Res (2015); 5(2)
- Ng &amp; Chan, IMECS (2012)