Impact of Visual Biofeedback of Trunk Sway Smoothness on Motor Learning during Unipedal Stance.

The assessment of trunk sway smoothness using an accelerometer sensor embedded in a smartphone could be a biomarker for tracking motor learning. This study aimed to determine the reliability of trunk sway smoothness and the effect of visual biofeedback of sway smoothness on motor learning in healthy people during unipedal stance training using an iPhone 5 measurement system. In the first experiment, trunk sway smoothness in the reliability group (n = 11) was assessed on two days, separated by one week. In the second, the biofeedback group (n = 12) and no-biofeedback group (n = 12) were compared during 7 days of unipedal stance test training and one more day of retention (without biofeedback). The intraclass correlation coefficient score 0.98 (0.93-0.99) showed that this method has excellent test-retest reliability. Based on the power law of practice, the biofeedback group showed greater improvement during training days (p = 0.003). Two-way mixed analysis of variance indicates a significant difference between groups (p < 0.001) and between days (p < 0.001), as well as significant interaction (p < 0.001). Post hoc analysis shows better performance in the biofeedback group from training days 2 and 7, as well as on the retention day (p < 0.001). Motor learning objectification through visual biofeedback of trunk sway smoothness enhances postural control learning and is useful and reliable for assessing motor learning.

Association of maximal voluntary isometric handgrip strength with age, gender and handedness in older people.

BACKGROUND: Maximal voluntary isometric handgrip strength (MVIHS) is influenced by age, sex, and handedness. AIM: To assess the association of MVIHS with age, sex, and handedness in older adults. MATERIAL AND METHODS: MVIHS was measured using a digital dynamometer in 60 men and 60 women aged 73 ± 6 years. Weight, height and handedness were also recorded. For analysis purposes, participants were divided into two age groups (65 to 70.9 years of age and ≥ 71 years). RESULTS: A negative correlation was observed between age and MVIHS in the non-dominant (r = -0.65 and -0.59 in men and women, respectively) and dominant hands (r = -0.71 and -0.64 in men and women, respectively). When age and MVIHS were correlated in the group aged 65-70 years, a significant correlation was observed in the non-dominant (r = -045 and -0.61 in men and women, respectively) and dominant hands (r = -0.47 and -0.64 in men and women, respectively). In the group aged ≥ 71 years, a stronger correlation with age was also observed in the non-dominant (r = -0.92 and -0.90 in men and women, respectively) and dominant hands (r = -0.95 and -0.90 in men and women, respectively). MVIHS was 2.8 to 8.9% lower in the non-dominant than in the dominant hand in all age groups. MVIHS was lower in women than in men in both age groups. CONCLUSIONS: MVIHS declines with age (especially after 71 years of age), is higher in men than women, and higher in the dominant than the non-dominant hand.

Association of maximal voluntary isometric handgrip strength with age, gender and handedness in older people / Fuerza de agarre isométrica máxima en relación a la edad, sexo y dominancia de mano

ABSTRACT Background: Maximal voluntary isometric handgrip strength (MVIHS) is influenced by age, sex, and handedness. Aim: To assess the association of MVIHS with age, sex, and handedness in older adults. Material and Methods: MVIHS was measured using a digital dynamometer in 60 men and 60 women aged 73 ± 6 years. Weight, height and handedness were also recorded. For analysis purposes, participants were divided into two age groups (65 to 70.9 years of age and ≥ 71 years). Results: A negative correlation was observed between age and MVIHS in the non-dominant (r = −0.65 and −0.59 in men and women, respectively) and dominant hands (r = −0.71 and −0.64 in men and women, respectively). When age and MVIHS were correlated in the group aged 65-70 years, a significant correlation was observed in the non-dominant (r = −045 and −0.61 in men and women, respectively) and dominant hands (r = −0.47 and −0.64 in men and women, respectively). In the group aged ≥ 71 years, a stronger correlation with age was also observed in the non-dominant (r = −0.92 and −0.90 in men and women, respectively) and dominant hands (r = −0.95 and −0.90 in men and women, respectively). MVIHS was 2.8 to 8.9% lower in the non-dominant than in the dominant hand in all age groups. MVIHS was lower in women than in men in both age groups. Conclusions: MVIHS declines with age (especially after 71 years of age), is higher in men than women, and higher in the dominant than the non-dominant hand.

Antecedentes: La fuerza de agarre isométrica voluntaria máxima (FAIVM) puede verse influenciada por la edad, el sexo y la dominancia. Objetivo: Describir la FAIVM y su relación con la edad, el sexo y la dominancia en adultos mayores. Material y Métodos: La FAIVM, la masa corporal, la talla, y la dominancia fueron medidas mediante protocolos estandarizados en 60 hombres e igual número de mujeres que fueron divididos en dos grupos acorde a su edad (65 a 70,9 años, y ≥ 71 años, respectivamente). Resultados: Se observó una correlación entre la edad y la FAIVM de mano no-dominante (hombres: r = −0,65; mujeres: r = −0,59) y dominante (hombres: r = −0,71; mujeres: r = −0,64). Al correlacionar la FAIVM y la edad en el grupo de 65-70 años, una correlación significativa fue observada en la mano no-dominante (hombres, r = −0,45; mujeres, r = −0,61) y mano dominante (hombres, r = −0,47; mujeres, r = −0,64). En el grupo ≥ 71 años, la edad tuvo una mayor correlación con la FAIVM de la mano no-dominante (hombres, r = −0,92; mujeres, r = −0,90) y mano dominante (hombres, r = −0,95; mujeres, r = −0,90). Comparada con la mano dominante, la mano no-dominante presentó menores valores de FAIVM en todos los grupos, variando entre −2,8 a −8,9%. Comparadas con los hombres, las mujeres presentaron menor FAIVM en mano dominante y no-dominante, en ambos grupos de edad. Conclusión: La FAIVM disminuye con la edad, especialmente desde los 71 años; es mayor en hombres comparados con mujeres y es mayor en mano dominante comparada con mano no-dominante.