This reports the results of analyzing the developmental process of muscular strength (grip strength) of Mlaburi people through infancy to adult ages.
1. The developmental process of muscular strength shows a sigmoid curve, so-called growth curve.
2. Comparing by sex, men exceed women in every age class.
3. The muscle development of men continues from 10 to around 20 yrs old, and women from 8 to 17 yrs old, including the adolescent spurt.
4. A small but apparent acceleration appears in men's infancy muscle development.
5. Grip strength-weight ratio was higher in Mlaburi group than in Japanese and Thai group in all age. This indicates that the environment of Mlaburi people required more physical use in their daily life.

Current of 21st century, in Demawso area, Kayah state, Myanmar, there are living Kayan women, so-called “Long neck tribes”. They go through their daily life wearing long neck rings and ankle rings for their entire lives.
In this research, we investigate the influence on growth shape wearing neck ring. We compare women group who wear neck rings (wearer group) with group who do not wear neck rings (non-wearer group) in Demawso area, Kayah state. The result are as follows, comparing the neck length of both groups in each age group.
1. Wearing neck ring begins from childhood, and it continues all through their lives.
2. There is no wearing influence from childhood to early part of adolescent period.
3. It starts to appear the influence of wearing neck ring from “age 11 to under 15 age group”, which we call it early part of adolescent period.
4. From “age 21 to under 30 age group”, the difference between two groups have increased tremendously. The value t shows t₀=2.703. We observe the significant difference of average value between the two groups.
5. From 30's onward, statistic significant difference could be detected in both groups.
6. In “Over age 60's”, neck length of “wearing group” is 12.18 cm. It is the longest length among all the age group. Neck length of “no-wearing group” is 7.65 cm, and the gap between “wearing group” and “non-wearing group” is 4.53 cm, and this gap is the biggest in all age group.
7. When height reaches the 140 cm at the early part of adolescent period, they wear much extended neck rings, and it will make big influence to growth & form afterward.
Considering the results mentioned above, we have investigated the influence on growth wearing neck ring in each age group. Wearing neck ring has big influence on the shape of women neck. In the near future, our research could be the valuable evidence for judging the matter of wearing neck ring.

Mlaburi people lived in the forests until the end of the 20th century and lived in hunter gatherers. In this study, we analyzed the data of a total of 124 people concerning the growth process of the Mlaburi's physique (body weight, sitting height, Body Mass Index). As a result, the following new findings were obtained.
1. About Mlabri's weight and sitting height, during the process of their adolescent growth, a period of females over males is continued for ten years.
2. Both males and females have a very long adolescence.
3. Throughout Mlabri's lifetime, the twenties are the heaviest.
4. Neither gender nor adolescent spurt at sitting height can be recognized.
5. In the overall observation of the lifetime, BMI can be divided into “Child's body type” and “Adult body type”. Obesity is not observed in Mlabri.