(?:
      (?! + w )
      [Ss]
 )*
 +
 ( w+ )                       # (1)
 (?:
      (?! + w )
      [Ss]
 )*

Regex1:   (+w+h?)|.+?
Options:  < none >
Completed iterations:   50  /  50     ( x 1000 )
Matches found per iteration:   49
Elapsed Time:    2.06 s,   2056.43 ms,   2056428 µs
Matches per sec:   1,191,386


Regex2:   (?:(?!+w)[Ss])*+(w+)(?:(?!+w)[Ss])*
Options:  < none >
Completed iterations:   50  /  50     ( x 1000 )
Matches found per iteration:   5
Elapsed Time:    1.00 s,   997.28 ms,   997281 µs
Matches per sec:   250,681

(+w+)