1. Hair growth rate
2. Shape of the hair
4. Method of Breakage.
Today here are another two potential reasons
African hair has more knots than any other hair type. In one study about 500 hair strands were taken from several volunteers. Amazingly (for me) Asian hair had no knots and only 2 were found in Caucasian hair. The African hair results – 10-15% of the hair had knots. Another study on curly Caucasian hair though seems to say that this type of hair experiences knots too (British Journal of Dermatology, Pages 169 – 173, 2006) . So why are knots such a big deal?
1. Harder for a comb to pass through
2. Cuticle gets damaged which is why knots should be cut off as the hair in the knot is probably very damaged
A South African study revealed that combing hair can have the same effect as a hair cut (Journal of the American Academy of Dermatology, Pages 886-888, 2006). The average hair length was much shorter than even the 4 inches per year growth rate. The type of comb used and whether or not wet combing was used was not reported. It does highlight however, the curlier the hair, the more gentle it needs to be handled
From my perspective, there are not enough studies on African hair for example some papers suggest that African hair may have a shorter growing phase or a longer resting phase but there is no evidence of this.
I do also wonder what exactly is long? Growing up in Kenya, among the people of African origin, the longest hair that I saw were two sisters with waist length hair. However, the average long haired person was shoulder length (usually somewhere past the shoulders but not quite at the armpit). I would estimate the hair length to be approximately 1 foot or 12 inches which runs hand in hand with the very controversial 4 inches per year growth rate and a 3 year growing phase.
How long is long hair to you?