This post is where I look into the growth of human height in smaller time intervals. We will go deeper into the progression of height increase during shorter time scales like during a 3 months cycle. I am hoping to see whether there are certain times when growth is fastest and when we figure out what these specific time intervals are, we can try to maximize and increase those time intervals for higher final height.
Abstract
The present paper links the two most contrasting aspects of auxology, and addresses the apparent discrepancy between the variability and pulsatility of short term individual growth, and the stability of population derived parameters. When body stature is measured at monthly intervals, an irregular incremental pattern becomes obvious, with a number of large scale components such as series of prepubertal and pubertal growth spurts, seasonal influences on height gain, and influences of the psychosocial and economic background. When measurement intervals decrease, the patterns of stature increment appear even more irregular, and a number of short scale components become apparent, that are distinct from measurement error. Observations are presented that suggest growth being a pulsatile, a periodic, a saltatory, respectively a chaotic event as suggested by some recent studies in animals and in human newborns. Accurate measurements of the lower leg at intervals of 24 hours support the idea of short term growth being characterized by chaotic series of ‘mini growth spurts’ that occur at intervals of approximately 4-9 days. The amplitude of mini growth spurts ranges between 2 and some 10 mm, and also growth velocity of each spurt varies considerably so that one spurt needs between less than one and up to several days for completion. The very opposite of the variability of individual growth was found in populations. A meta-analysis of 40 male and 51 female European and US American growth studies revealed an almost uniform general pattern of average stature increment during the last 100 years. An additional analysis of stature variation of very large Japanese and Czechoslovakian growth surveys, with all together more than 23000000 measurements, and more than 500000 German preschool and school measurements, suggested similar uniformity in the standard deviation of stature.
Study #2: The analysis of short-term growth.
Abstract
The analysis of short-term growth needs repetitive measurements of body stature or of segments of the body. When body stature is measured at monthly intervals, an irregular incremental pattern becomes obvious with a number of large-scale components such as series of prepubertal and pubertal growth spurts, seasonal influences on height gain, and influences of the psychosocial and economic background. When measurement intervals decrease, incremental patterns appear even more irregular, and a number of short-scale components become apparent that are distinct from measurement error. The review summarizes the analysis of short-term growth, and presents the current findings supporting different views on how growth progresses at short term. In particular, observations are presented that suggest growth being a pulsatile, a periodic, a saltatory, and a chaotic event. Some recent animal studies and studies in human newborns are added in detail as they illustrate short-term growth on the basis of accurate 24-hour measurements of the lower leg. The latter investigations support the idea of short-term growth being characterized by chaotic series of’mini growth spurts’ that occur at intervals of approximately 4-5 days, not only in human neonates, but also in rats. The amplitude of mini growth spurts ranges between 2 and some 10 mm, and growth velocity of each spurt also varies considerably so that one spurt needs between less than 1 and up to several days for completion.
Study #3: Periodical changes of short term growth velocity (‘mini growth spurts’) in human growth.
Abstract
Evidence has accumulated that predictions of annual or half-annual growth rates are of limited validity when derived from extrapolations of short term growth rates. In order to investigate whether the poor predictive qualities of short sections of individual growth curves are caused by non-linearity of human growth, we have studied 73 healthy children, aged 2.9 to 15.9 years, with standard deviation scores for body height ranging between -3.3 and +3.0. The children were measured between 18 and 106 times once or twice per week throughout periods of 180 to 306 days by knemometry, a novel and noninvasive technique of accurate lower leg length measurement. Non-linearity of growth was found in about 70% of those children who could be measured more than 35 times. 45 children provided evidence for a characteristic up-and-down pattern of lower leg growth velocity consisting of sharp growth spurts (‘mini growth spurts’) alternating with periods of decreased growth velocity every 30 to 55 days. This pattern seemed to appear spontaneously, though in some cases we found a marked coincidence between periods of growth arrest and intermittent infectious illness.
Study #4: Knemometry, a new tool for the investigation of growth. A review.
Abstract
Cross-sectional and longitudinal studies of human growth have revealed almost every detail of the typical human growth pattern. Yet, the description of this pattern is still limited to the traditional vocabulary of “growth rates”, i.e. height or length differences divided by certain time intervals such as months or years. Almost no information is yet available on finer details of this pattern. This review concerns the existing experimental and clinical data collected by a novel and non-invasive technique of accurate lower leg length measurement named “knemometry” that has been used for the study of short-term growth. This technique estimates the distance between heel and knee of the sitting child with an accuracy (technical error) of 0.09-0.16 mm. Several authors have presented evidence that lower leg growth is non-linear. There is not only a marked day-to-day variation of the lower leg length which far exceeds the error of the measurement itself, but there is also a characteristic up-and-down pattern of lower leg growth consisting of sharp growth spurts (“mini-growth-spurts”) alternating with periods of decreased growth velocity every 30-55 days in 45 out of 73 healthy children. This pattern can be visualized by the calculation of “mean daily lower leg growth velocities”, an approach that gives information on the kinetic properties of the growth process. In spite of much initial criticism, knemometry has opened a fascinating new dimension of the physiology of human growth and provided finer details of growth than hitherto obtainable by conventional techniques of growth measurement.
Analysis & Interpretation:
The first study starts off by noting that when researchers actually tried to measure the growth rate in terms of height difference for intervals of short time duration, like around each month, the growth chart is irregular. There seem to be sections of time where growth is large, and others where there is no growth at all. When the time interval is shorten further down to maybe each week, the growth increments become even more irregular. As the researchers suggest, growth is like …being a pulsatile, a periodic, a saltatory, respectively a chaotic event as suggested by some recent studies in animals and in human newborn.” It seems that there are these “mini-growth spurts” which occur in 4-9 days intervals. The incremental nature is chaotic and range from 2-10 mm in longitudinal growth. The velocity of growth also is extremely varied from the range of less than 1 day to several days to get reach the amount of bone length difference.
When a meta-analysis is done of large groups of subjects, it appears that even though for the short term growth, everything is irregular, the overall growth progression is actually uniform.
It seems that study #2 just repeats the abstract and results of the 1st study. It is again noted that the mini-growth spurts are actually around 4-5 days long and the rate or velocity of growth can be very varied as well. The way the measurement of growth velocity is done is by measuring the lower leg bone. What is interesting to note about the 2nd study is that the growth irregularity found in humans are exhibited by lab rats as well. Maybe this means that the growth pattern for short terms is the same for most animals.
The 3rd study places more evidence towards the idea that whatever one might measure in terms of growth rate for the short term can not really be used to calculate the growth rate for the long term. The researchers were trying to…”…to investigate whether the poor predictive qualities of short sections of individual growth curves are caused by non-linearity of human growth,…” 73 healthy children had their lower leg measured using the technique known as knemometry in a varied time frame (180-360 days) and at varied frequencies (18-100 times a day). In the children measured more than 35 times, around 70% of them showed nonlinear growth increments. Around 45 of the children showed an up and down pattern of high growth velocity aka mini-growth spurt followed by around 30-55 days of no or minimal increase. What is interesting to note is that the researchers observed that a lot of the decreased growth time intervals coincided with infectious illness times.
The 4th study was a review of the data found from clinical using something known as Knemometry. It is a novel and non-invasive technique of accurate lower leg length measurement that has been used for the study of short-term growth. This technique estimates the distance between heel and knee of the sitting child with an accuracy (technical error) of 0.09-0.16 mm. The researchers note of the same study that…
“There is not only a marked day-to-day variation of the lower leg length which far exceeds the error of the measurement itself, but there is also a characteristic up-and-down pattern of lower leg growth consisting of sharp growth spurts (“mini-growth-spurts”) alternating with periods of decreased growth velocity”
The last study I have put in the post just shows that the technique of measuring the lower leg bone called knemometry is now being looked at in the field of auxology has been very effect in showing that human growth in short time periods is very irregular