Pubertal growth of 1,453 healthy children according to age at pubertal growth spurt onset. The Barcelona longitudinal growth study

Physical strength levels and short-term memory efficiency in primary school children: a possible match?

BACKGROUND

Physical strength stimulation and, in general, physical activity induces brain plasticity (functional and structural adaptations) in different cerebral areas, benefiting executive function, cognition, attention and academic performance, which is usually estimated by measuring the Intelligent Quotient (IQ), and IQ is related to short-term memory, generally during school age. However, very little is known about the role of physical strength on short-term memory efficiency. Therefore, the primary aim of this study is to examine whether the level of physical strength can positively impact short-term memory efficiency in primary school children. Additionally, if this effect is observed, the secondary goal of this study is to determine whether the age of the participants plays a role in mediating and moderating this influence.

METHODS

Seventy-five children from a primary school in the metropolitan area of Turin were recruited for this study. Each subject performed the overhead medicine ball toss (backwards) test to assess physical strength and the Digit Span test from the Wechsler Intelligence Scale for Children (WISC) to evaluate short-term memory efficiency. Firstly, a simple mediation model was used to identify the possible impact of physical strength levels on short-term memory efficiency and the potential role of participants' chronological age. Secondly, a moderation model was carried out to observe if age could moderate the impact of physical training on short-term memory efficiency and the different significance levels of the moderator. Significance was assumed at P<0.05.

RESULTS

The results showed a statistically significant direct effect of physical strength on short-term memory (Β=0.429, t(72)=3.247, P<0.01). On the contrary, age was not statistically significant (Β=0.167, t(72)=3.247, P=0.211). Furthermore, a significant interaction between strength and age was identified by the moderation model (β=-0.270, P<0.01). Specifically, the impact of physical strength levels on short-term memory increased for individuals who were above the mean age (β=0.755, P<0.001). but not for those under the mean age (β=0.215, P=0.153). This model explains 37.2% of the variance in memory (R2=0.372, F(3, 71)=14.031, P<0.001).

CONCLUSIONS

These findings suggest that physical strength can positively influence short-term memory. In addition, this impact is enhanced in older-age children. Thus, primary school programs should stimulate physical strength to help children develop cognitive abilities.

A new type of pubertal height reference based on growth aligned for onset of pubertal growth

Objectives Growth references of today traditionally describe growth in relation to chronological age. Despite the broad variation in age of pubertal maturation, references related to biological age are lacking. To fill this knowledge gap, we aimed to develop a new type of pubertal height reference for improved growth evaluation during puberty, considering individual variation in pubertal timing. Methods Longitudinal length/height measures were obtained from birth to adult height in 1,572 healthy Swedish children (763 girls) born at term ∼1990 to nonsmoking mothers and Nordic parents, a subgroup of GrowUp1990Gothenburg cohort. A total height reference was constructed from Quadratic-Exponential-Puberty-Stop (QEPS)-function-estimated heights from individual height curves that had been aligned for time/age at onset of pubertal growth (5% of P-function growth). References that separated growth into specific pubertal heightSDS (P-function growth) and basic heightSDS (QES-function growth) were also generated. Results References (cm and SDS) are presented for total height, and height subdivided into that specific to puberty and to basic growth arising independently of puberty. The usefulness of the new pubertal growth reference was explored by identifying differences in the underlying growth functions that translate into differences in pubertal height gain for children of varying body mass, height, and with different pubertal timings. Conclusions A new type of height reference allowing alignment of individual growth curves, based on the timing of the pubertal growth spurt was developed using QEPS-model functions. This represents a paradigm shift in pubertal growth research and growth monitoring during the adolescent period.