Issue in executing loops in R

I am trying to make loops to calculate Speed for all "Longitude, Latitude and Timestamp" points. But loops are not working. Based on Min and Max values of a Speed i am filtering the points and saving them in other vectors. I just want to save latitude and longitude in one vector which satisfy condition of a Speed and save remaining latitude and longitude in other vector. Thanks

i = 1
j = i + 1
distt <<- 0
time_TT <- 0
#Speed 
MIN <- 0.001
MAX <- 0.002
LON_S <-0
LAT_S <-0
z<-2
LON_SS <- 0
LAT_SS <- 0 



while (i < length(longitude))
{
  library(geosphere)
  dist <- distm (c(longitude [j],Latitude[j]), c(longitude [i],Latitude[i]), 
  fun = distVincentyEllipsoid)
  distt <- append(distt, dist)
  time_vector <- time[j] - time[i]
  time_TT <- append(time_TT, time_vector*60)  # converting mints into 
  seconds 
  speed <- distt/time_TT
  speed <- round(speed, 3)

  if ((speed[z] >= MIN) & (speed[z] <= MAX))
  {
    #speed is inside the range

    LON_S  <- append(LON_S, longitude [j])
    LAT_S  <- append(LAT_S, Latitude[j]) 
    z <- z + 1
  }
    #speed is outside the range

  LON_SS  <- append(LON_SS, longitude [j])
  LAT_SS  <- append(LAT_SS, Latitude[j]) 
  z <- z + 1

  i = j; break 
  j <- j + 1