A foot bar support assembly movably carried by {HEAD ~ each} of the outwardly open slots supports {TAIL ~ the foot bar} 
A foot bar support assembly movably carried by { HEAD ~ each } of the outwardly open slots supports { TAIL ~ the foot bar }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL