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The traditional classifications of motor skills nature (open vs closed; fine vs gross) have not been considered in handedness investigations. Instead, previous research focused on comparing complex vs less complex motor behaviour, leaving a gap in the literature. We compared manual preference between different motor skill characteristics, namely: fine and closed (FC), gross and closed (GC) and gross and open (GO) tasks. The hand preference was assessed with the Global Lateral Preference Inventory in four hundred and forty participants (244 women) aged from 18 to 59 years old. By assessing the degree and direction of handedness in different motor skills, our results showed a stronger lateralization pattern for FC motor skills as compared to GC and GO, with GO also being less lateralized than GC. Our results expand those of previous investigations that used the motor skill complexity definitions by showing how handedness can also be modulated by the interaction between classic motor skills classifications. Future research should consider fine vs. gross and open vs. closed classifications when selecting tasks for analysis of asymmetries of preference.

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There are a variety of inventories available to evaluate human lateral preference, but no previous review has systematically analyzed and compared them. We conducted a systematic literature review to identify these inventories and describe their characteristics (e.g., dimensions, scales, tasks, psychometric properties). We included 26 articles, each presenting a different inventory to assess lateral preference, published between 1900 and 2022, selected from the following databases: PubMed, SportDiscus, APA PsycNET, and Web of Science. These inventories analyzed tasks performed in everyday life (domestic, work-related, sports, and leisure/recreation activities), covering hand, foot, hearing, visual and other non-usual lateral preference dimensions, such as trunk and head. Most inventories classified individuals based on the direction (left, indifferent or right preference) and degree (consistent or moderate) of laterality. However, many of the reviewed inventories lack established psychometric verification in their original publication, such as validity, reliability, responsiveness, and practical applicability. Inventories also presented tasks that may be specific to a given cultural setting, limiting their application across different countries. Based on these findings, we provide a comprehensive guide for researchers to select a lateral preference assessment tool, but also advocate for a new inventory with a broader approach, containing more than one dimension of lateral preference (i.e., not only handedness) and tasks that are common to different cultures to enhance practical applicability worldwide.

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Between-arm performance asymmetry can be seen in different arm movements requiring specific interjoint coordination to generate the desired hand trajectory. In the current investigation, we assessed between-arm asymmetry of shoulder-elbow coordination and its stability in the performance of circular movements. Participants were 16 healthy right-handed university students. The task consisted of performing cyclic circular movements with either the dominant right arm or the nondominant left arm at movement frequencies ranging from 40% of maximum to maximum frequency in steps of 15%. Kinematic analysis of shoulder and elbow motions was performed through an optoelectronic system in the three-dimensional space. Results showed that as movement frequency increased circularity of left arm movements diminished, taking an elliptical shape, becoming significantly different from the right arm at higher movement frequencies. Shoulder-elbow coordination was found to be asymmetric between the two arms across movement frequencies, with lower shoulder-elbow angle coefficients and higher relative phase for the left compared to the right arm. Results also revealed greater variability of left arm movements in all variables assessed, an outcome observed from low to high movement frequencies. From these findings, we propose that specialization of the left cerebral hemisphere for motor control resides in its higher capacity to generate appropriate and stable interjoint coordination leading to the planned hand trajectory.

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ABSTRACT: Nunes, JP, Marcori, AJ, Ribeiro, AS, Cunha, PM, Kassiano, W, Costa, BDV, Aguiar, AF, Nakamura, M, Mayhew, JL, and Cyrino, ES. Differential responsiveness for strength gain between limbs after resistance training in older women: Impact on interlimb asymmetry reduction. J Strength Cond Res 36(11): 3209-3216, 2022-The present study compared strength responses between preferred (PREF) and nonpreferred (N-PREF) legs in older women. Muscular strength was measured unilaterally using an isokinetic dynamometer and was analyzed for reproducibility scores, acute performance, and responsiveness to a resistance training (RT) program. One hundred eleven women (aged ≥60 years) performed 12 weeks of whole-body RT (3 times a week; 4 lower-body exercises). Reproducibility scores (intraclass correlation coefficient ≥0.920; following test-retests in part of the sample at pretraining; n = 19), average acute performances, and average strength gains (PREF = ∼6.9%; N-PREF = ∼7.2%) were similar between legs (p > 0.05). However, the individual analyses showed that some subjects were considered responders to strength gains in 1 leg, whereas nonresponders in the other. Nonetheless, when considering the responses in all strength tests, most subjects (91%) were considered responder to at least 1 measure. In addition, it was observed that the strength ratio between PREF/N-PREF legs was altered for those who presented some asymmetry at baseline, as the limbs became more symmetrical in all strength measures after the RT. In conclusion, we observed that some older women may have different levels of strength between legs; however, a traditional 12-week RT program with bilateral exercises can reduce such asymmetry by inducing greater strength gains in the weaker leg.

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Transcultural approaches comparing the distribution of lateral preference between countries focused primarily on handedness. However, other laterality dimensions may also be susceptible to cultural variations. The present study compared lateral preference in five dimensions (hand, foot, trunk, hearing, and visual) of young adults from Brazil and Mozambique. Two hundred and two undergraduate students participated in the study, of which 101 were Brazilian (21.7 ± 1.66 years old) and 101 Mozambican (25.6 ± 6.2 years old). The participants' lateral preference direction and degree were assessed using the global lateral preference inventory. Most Brazilians were classified in the moderate preference category, while Mozambicans had a higher frequency of individuals with strong preferences. Hence, Mozambicans presented a higher lateralization degree for all dimensions. A subsequent analysis considering only preference direction (right, left or indifferent), and not degree, did not show the same outcomes, revealing similarities in preference distribution between the two groups. This finding highlights the necessity to incorporate preference degrees in future analysis to not overlook potential differences. We also conclude lateral preference investigations with transcultural approaches should analyse beyond handedness, as other dimensions can also be modulated by cultural characteristics.

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Single leg balance training promotes significant increments in balance control, but previous reviews on balance control have not analyzed this form of balance training. Accordingly, we aimed to review the single leg balance training literature to better understand the effects of applying this training to healthy individuals. We searched five databases-PubMed, EMBASE, Scopus, Lilacs, and Scielo-with the following inclusion criteria: (a) peer-reviewed articles published in English; (b) analysis of adult participants who had no musculoskeletal injuries or diseases that might impair balance control; and (c) use of methods containing at least a pre-test, exclusive single leg balance training, and a post-test assessment. We included 13 articles meeting these criteria and found that single leg balance training protocols were effective in inducing balance control gains in either single- or multiple-session training and with or without progression of difficulty. Balance control gains were achieved with different amounts of training, ranging from a single short session of 10 minutes to multiple sessions totaling as much as 390 min of unipedal balance time. Generalization of balance gains to untrained tasks and cross-education between legs from single leg balance training were consistent across studies. We concluded that single leg balance training can be used in various contexts to improve balance performance in healthy individuals. These results extend knowledge of expected outcomes from this form of training and aid single leg balance exercise prescription regarding volume, frequency, and potential progressions.

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In elite-level soccer, the ability to take shots with both limbs from different positions in the pitch may be key to success. This research aimed to: 1) analyze footedness of elite-football players in European leagues during shooting by computing frequency of right- and left-foot use and accuracy; and 2) investigate whether an athlete's distance from the target (goal, penalty, and outside penalty area) and pitch zone (center, left, or right from the goal) can constrain foot selection during shooting. We analyzed 1826 games from the 2017/18 season, divided between: Spanish LaLiga (380 matches); Italian Serie A (380 matches); English Premier League (380 matches); German Bundesliga (306 matches); and French Ligue 1 (380 matches). Results revealed asymmetrical proportions of foot selection, favoring the preferred foot for right- and left-footed athletes. Frequency of preferred foot selection increased as a function of distance from the target (i.e., the farther the athlete, higher the percentage of preferred foot selection). Shots taken from the left side were more often performed with the right foot and vice-versa, for both left- and right-footed athletes. Interestingly, asymmetries were observed only in foot selection, but not in performance, as success rate did not vary between limbs in any position.

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According to the dynamic dominance model, the left cerebral hemisphere is specialized for the control of intersegmental dynamics and the right hemisphere for impedance control. Our aim was to test predictions from the dynamic dominance model in children by comparing performance between the right (preferred) and left hands in aiming. Three groups were compared: 4-7, 8-11, and 18-38 years old. Results showed higher movement linearity in the performance with the right hand in all age groups (P < .01), while initial directional error and endpoint accuracy were equivalent between hands. These results provided partial support for the dynamic dominance model.

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Interlateral transfer of learning between the legs in body balance training is a topic of theoretical and practical interest, but it has been left untouched in previous research. In this investigation, we aimed to evaluate the magnitude and asymmetry of interlateral transfer of balance stability following the practice of a challenging task of unipedal support on an unstable base. Thirty participants (18-30 years old) were assigned to two groups practicing either with the right or the left leg. Training consisted of a single practice session of unipedal balance on a platform free to sway in the anteroposterior direction. Balance time (off ground) of either leg in 10-s trials was compared across pre-test, post-test, and 7-day retention. Post-test indicated that both groups had similar performance gains with the trained leg, and equivalent transfer to the transfer leg. Analysis of retention indicated further balance improvement with both transfer legs, while practice with the right leg led to the superior transfer to the untrained leg as compared to the opposite transfer direction. These results suggest that persistent transfer of learning effects for unipedal dynamic balance is bilateral but more prominent in the right-to-left direction.

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Tomeleri, CM, Nunes, JP, Souza, MF, Gerage, AM, Marcori, A, Iarosz, KC, Cardoso-Júnior, CG, and Cyrino, ES. Resistance exercise order does not affect the magnitude and duration of postexercise blood pressure in older women. J Strength Cond Res 34(4): 1062-1070, 2020-The aim of this study was to compare the effects of 2 resistance exercise order on postexercise blood pressure (BP) in trained nonhypertensive older women. Sixteen women (68.3 ± 3.3 years, 63.5 ± 11.6 kg, 157.5 ± 5.1 cm) performed 2 sessions with 8 exercises (3 sets of 8-12 repetitions) in distinct orders (from multi- to single-joint exercises [MS] or from single- to multijoint exercises [SM]) and a control session (CS), without exercise. Blood pressure and heart rate (HR) were obtained pre- and postsessions (60 minutes). Postexercise hypotension was observed for systolic BP (SBP) and mean BP in both the MS session (SBP: -6.9 mm Hg, mean BP: -3.3 mm Hg, p ≤ 0.05) and SM session (SBP: -4.6 mm Hg; mean BP: -1.1 mm Hg). Postexercise HR was higher than presession values until 30 minutes of recovery in both training sessions. Furthermore, SBP and mean BP, and HR were lower than the values obtained in the CS (30-60 minutes and 0 minutes, respectively; p ≤ 0.05). There were no differences between the SM and MS sessions in any variable or at any moment. In conclusion, resistance exercise order does not interfere in the magnitude and duration of postexercise hypotension in trained nonhypertensive older women.

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Handedness ontogenesis is still under debate in science. This systematic review analyzed articles regarding the theories and basis of handedness formation, highlighting the historical knowledge path that this literature underwent. Cochrane Library, LILACS, Web of Sciences, Science Direct and PubMed databases were searched. This review included review studies with handedness as the main topic. Only papers written in English with analyses exclusively in neurotypical humans (any age range) were included. Different approaches (genetic, neural, social, and behavioural) were reviewed in light of growing evidence, summarizing the current state of the art. Genetic and environmental/social impacts are common points in most of the reviews, each given more or less importance, depending on the author and theory proposed. Multifactorial, developmental approaches to handedness formation seem to be the most up to date view of the phenomenon. Different control mechanisms between hemisphere and neural asymmetries are also contributing factors to handedness formation.

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The aim of this study was to compare the acute effects of four resistance-training (RT) exercise orders on rate of perceived exertion (RPE) and RT variables with exercise load properly adjusted according to its position within the sequence in older women. That is, the load was adjusted so that it was possible that the sets were performed within the repetition-zone established. Fifteen trained older women (67.4 ± 5.3 years) participated in a crossover-design, combining single-joint (SJ) and multi-joint (MJ) exercises for upper-(UB) and lower-body (LB) in the following exercise orders: SEQA = UBMJ-UBSJ-LBMJ-LBMJ; SEQB = UBSJ-UBMJ-LBSJ-LBMJ; SEQC = LBMJ-LBSJ-UBMJ-UBSJ; SEQD = LBSJ-LBMJ-UBSJ-UBMJ. Each session was comprised of eight exercises with 3 sets of 8-12 repetitions. RPE was analyzed by a sequence (4) × sets (3) two-way ANOVA. Repetitions, time under tension, load, volume-load, and the average RPE of the session were analyzed by one-way ANOVA comparing the four sequences. No significant difference was identified between conditions for total repetitions, time under tension, training load, and volume-load. Lower average RPE of the session was obtained when LB exercises were performed earlier (SEQA: 7.2 ± 1.2, SEQB: 7.1 ± 1.0, SEQC: 6.7 ± 0.9, SEQD: 6.3 ± 1.1). We conclude that when lower body exercises are performed first in a training session, a lower RPE is noted throughout all the session.

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Lateral preference is influenced by many different factors. Although studies that assessed handedness contributed greatly to our understanding of the phenomenon, looking to other dimensions of motor laterality, such as lower limbs, trunk, visual and hearing preference, may be an interesting strategy to further advance in the field. Comparing different age groups with a complete inventory also contributes to understanding the ageing impact on these variables. Our aim, therefore, was to assess six motor laterality dimensions in younger adults and older people. Two hundred subjects participated in this study (102 adults, 30.6 ± 11.2 years old, and 98 elders, 70.4 ± 7.22 years old) and lateral preference was assessed by the Global Lateral Preference Inventory. We verified significant differences between groups in all dimensions, except the visual one, with proportionally stronger right preference in the older group. Compared to other dimensions, higher frequency of ambidexterity was observed in trunk, hearing and visual preference for both groups. These results might indicate that lateral preference is, indeed, multifactorial, being affected by ageing, task complexity and other possible related aspects.

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Objetivo: Analisar o efeito de contrações voluntárias isométricas máximas e da eletroestimulação no torque isométrico e na ativação muscular do tríceps braquial em adultos fisicamente ativos. Métodos: Dezenove homens foram submetidos a testes de força isométrica (FI) como pré-teste, por meio de contração voluntária isométrica máxima durante 10 segundos e atividades condicionantes (ACs) randomizadas: isometrias durante 7, 10 e 12 segundos e eletroestimulação em 70 e 120Hz por 10 segundos cada. Após as ACs, foram realizadas duas contrações voluntárias isométricas máximas de 10 segundos com intervalo de 4 e 8 minutos, respectivamente. A atividade elétrica do tríceps braquial (porções medial e lateral) foi registrada. Resultados: Não foi verificado efeito em nenhuma das condições para o torque máximo ou médio, bem como para atividade elétrica do tríceps braquial (P>0,05). Conclusão: O intervalo adotado entre as ACs e o teste de FI não foi suficiente para induzir a melhoria do torque isométrico. (AU)

Objective: To analyze the effect of maximal voluntary isometric contractions and of electroestimulation on isometric torque and muscle activation of the brachii triceps in physically active adult males. Methods: Nineteen men underwent isometric force tests as pre-test, through 10-second long maximal voluntary isometric contractions and conditioning activities randomized: isometric contraction during 7, 10 and 12 seconds and electric stimulation in 70 and 120 Hz for 10 seconds each. After the conditioning activities, two voluntary isometric contractions were performed for 10 seconds with interval of 4 and 8 minutes, respectively. The muscle electrical activity of brachii triceps (medial and lateral portion's) was measured. Results: It was not verified effect in any conditions to maximal or mean torque (P>0.05), likewise to muscle electrical activity of brachii triceps (P>0.05). Conclusion: The interval adopted among the conditioning activities and the isometric force test was not enough to induce the isometric torque improvement. (AU)

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This study analyzed the effects of 12 weeks of resistance training (RT) on resting blood pressure (BP) and plasma levels of nitric oxide metabolites (NOx) in pre- and hypertensive older women, and evaluated the relationship between these 2 parameters. Thirty-five older women (68.2±5.7 years, 70.0±14.4 kg, 157.1±6.4 cm, 28.3±5.0 kg.m-2) were randomly allocated into a training group (TG; n=17), which performed a 12-week RT program, and a control group (CG; n=18), which did not perform any physical exercise. Anthropometry, one repetition maximum (1RM), body composition analysis by dual energy X-ray absorptiometry, blood samples, and resting BP were measured. There was a significant interaction for all variables analyzed, in which reductions of systolic BP (-8.5%), diastolic BP (-8.4%), and mean arterial pressure (-8.5%), and increases of NOx (+35.2%) were observed only for the TG. Moreover, a negative and significant correlation was observed (P<0.05; r=-0.63) between NOx and systolic BP in the TG. Results suggest that a 12-week RT program is sufficient to induce reductions in BP in pre- and hypertensive older women and that the decrease in systolic BP is associated with an increase in plasma NOx concentration.

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