Influence of the age on self regulation of static grip forces from perceived exertion values

The effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes

It has been suggested that athletes with longer fingers and larger hand surfaces enjoy stronger grip power. Therefore, some researchers have examined a number of factors and anthropometric variables that explain this issue. To our knowledge, the data is scarce. Thus, the aim of this study was to investigate the effect of hand dimensions, hand shape and some anthropometric characteristics on handgrip strength in male grip athletes and non-athletes. 80 subjects aged between 19 and 29 participated in this study in two groups including: national and collegian grip athletes (n=40), and non-athletes (n=40). Body height and mass were measured to calculate body mass index. The shape of the dominant hand was drawn on a piece of paper with a thin marker so that finger spans, finger lengths, and perimeters of the hand could be measured. The hand shape was estimated as the ratio of the hand width to hand length. Handgrip strength was measured in the dominant and non-dominant hand using a standard dynamometer. Descriptive statistics were used for each variable and independent t test was used to analyze the differences between the two groups. The Pearson correlation coefficient test was used to evaluate the correlation between studied variables. Also, to predict important variables in handgrip strength, the linear trend was assessed using a linear regression analysis. There was a significant difference between the two groups in absolute handgrip strength (p<0.001) and handgrip/height ratio (p<0.001). The indices of body height, body mass, lean body mass and body fat content (p<0.001) were significantly greater in grip athletes. All hand variables except FS1-4 (p>0.05) were significantly different between the groups (p<0.001). After controlling body mass all hand anthropometric characteristics except thumb length (r=0.240, p= 0.135), hand shape (r=-0.029, p=0.858), middle finger length (r=0.305, p=0.056) and forearm circumference (r=0.162, p=0.319) significantly correlated with handgrip strength in grip athletes, but not in non-athletes, except for forearm circumference (r=0.406, p=0.010). The results showed that handgrip strength and some of the hand dimensions may be different in athletes who have handgrip movements with an object or opponent in comparison to non-athletes. Also, there was a significant positive correlation between handgrip strength and most of the hand dimensions in grip athletes. Therefore, these can be used in talent identification in handgrip-related sports and in clinical settings as well.

Salivary hormonal responses to different water-based exercise protocols in young and elderly men

Although adaptations to water-based resistance exercise and conventional water-based exercise have been investigated, little is known regarding acute anabolic and catabolic hormonal responses to these 2 types of exercise. The purpose of this study was to investigate the acute responses of salivary testosterone and cortisol to 2 water-based exercise protocols in which the different intensities were determined using Borg's perceived exertion scale. Ten young (24 +/- 2.7 yr) and 7 elderly men (65 +/- 5.5 yr) who were familiar with exercise in water were subjects of the study. Salivary samples were collected at rest and 5 minutes after the 2 water-based exercise protocols. One session involved intermittent water resistance training at a Borg-scale intensity of 19 (W19), whereas the other involved continuous water aerobic training at an intensity of 13 (W13). The samples were used to determine salivary levels of free testosterone and cortisol. There was a significant increase on salivary testosterone in both groups after the W19 protocol (p < 0.05), but no such alteration was observed after W13. The testosterone response to the W19 protocol was significantly higher in young than in elderly men (p < 0.05). Although no modification on salivary cortisol was observed after either protocol, in young men, the cortisol response to W19 was higher than in elderly men (p < 0.05). Water-based exercise with emphasis on strength development was found to stimulate a more acute increase on salivary testosterone than water-based aerobic exercise, probably as a result of the higher intensity used in that training protocol. Given the known relationship between acute hormonal responses and chronic neuromuscular adaptations, the testosterone response after W19 should be considered when prescribing water-based exercise, especially to older populations.

Validation of a pictorial rating scale for grip strength evaluation in 3- to 6-year-old children

The present study aimed to validate a pictorial rating scale to evaluate the child's ability to produce grip forces. Thirty-seven children aged 3 to 6 years participated as subjects in this investigation. We used a tailor-made pictorial scale and a hand grip strength meter, as well as a Piaget's clinical interview aimed to gather information on the child's understanding of the rating scale. The sensitivity of the rating scale was measured by testing a 4-intensity-level hand grip effort with 3- to 6-year-old children. In addition, the reproducibility of this pictorial rating scale was investigated by a test and randomised re-test procedure. Statistical analysis revealed that no significant main effect (P>0.05) for test was observed in any child. In addition, no significant main effect (P>0.05) for intensity was found in 3-year-old children. However, in the 4-year-old children and over, a significant main effect (P<0.05) was found for intensity. The results also showed that 5- and 6-year-old children were able to produce four differentiated intensities of grip forces. These findings suggest that the pictorial rating scale for grip strength evaluation showed acceptable reproducibility and was sensitive to the age of the children tested. To conclude, this pictorial rating scale appears to be a valid tool to investigate accurately the child's ability to produce grip forces in young children from 5-year-old and over.

Perceived exertion : influence of age and cognitive development

Because little is known about the effects of aging on perceived exertion, the aim of this article is to review the key findings from the published literature concerning rating of perceived exertion (RPE) in relation to the developmental level of a subject. The use of RPE in the exercise setting has included both an estimation paradigm, which is the quantification of the effort sense at a given level of exercise, and a production paradigm, which involves producing a given physiological effort based on an RPE value. The results of the review show that the cognitive developmental level of children aged 0-3 years does not allow them to rate their perceived exertion during a handgrip task. From 4 to 7 years of age, there is a critical period where children are able to progressively rate at first their peripheral sensory cues during handgrip tests, and then their cardiorespiratory cues during outdoor running in an accurate manner. Between 8 and 12 years of age, children are able to estimate and produce 2-4 cycling intensities guided by their effort sense and distinguish sensory cues from different parts of their body. However, most of the studies report that the exercise mode and the rating scale used could influence their perceptual responsiveness. During adolescence, it seems that the RPE-heart rate (HR) relationship is less pronounced than in adults. Similar to observations made in younger children, RPE values are influenced by the exercise mode, test protocol and rating scale. Limited research has examined the ability of adolescents to produce a given exercise intensity based on perceived exertion. Little else is known about RPE in this age group. In healthy middle-aged and elderly individuals, age-related differences in perceptual responsiveness may not be present as long as variations in cardiorespiratory fitness are taken into account. For this reason, RPE could be associated with HR as a useful tool for monitoring and prescribing exercise. In physically deconditioned elderly persons, a rehabilitation training programme may increase the subject's ability to detect muscular sensations and the ability to utilise these sensory cues in the perception of effort. RPE appears to be a cognitive function that involves a long and progressive developmental process from 4 years of age to adulthood. In healthy middle-aged and elderly individuals, RPE is not impaired by aging and can be associated with HR as a useful tool to control exercise intensity. While much is known about RPE responses in 8- to 12-year-old children, more research is needed to fully understand the influence of cognitive development on perceived exertion in children, adolescents and elderly individuals.

Learning to produce predicted static handgrip forces

The objective of this study was to prove the hypothesis that kinaesthetic sensations, without visual or verbal guidance, give sufficient information to produce predictive handgrip forces. The ability of 70 girls and 70 boys aged 11 to 17 years to produce predicted static handgrip force was examined. The subjects were requested to produce 50% of their individual maximum handgrip force and maintain it for 2 seconds without visual control. Ten trials were done first by the right-hand and then by the left-hand. The maximum grip strength increased parallel with age, but significant differences were found between both the right and the left-hand, and the genders. Close correlations were found between the desired and the exerted forces. The differences between the desired forces and the exerted forces produced by the fifth trials were significantly smaller than that of the first trials. The verbal information about each exerted force contributed to the learning with right-hand since it caused a further decrease in the difference between the desired force and the exerted force. In contrast, the learning with left-hand was not enhanced by verbal feedback. These results suggest that kinaesthetic feedback information from the hand plays an effective role in learning to produce predicted grip strengths without visual and verbal information.