RESUMEN

Differences in coordination and coordinative variability are common in people with low back pain. While differences may relate to the different analyses used to quantify these metrics, the preferred approach remains unclear. We aimed to compare coordination and coordinative variability, in people with and without low back pain performing a lifting/lowering task, using continuous relative phase and vector coding procedures, and to identify which technique better detects group differences. Upper lumbar (T12-L3), lower lumbar (L3-S1), and hip angular kinematics were measured using electromagnetic motion capture during 10 crate lifting/lowering repetitions from adults with (n = 47) and without (n = 17) low back pain. Coordination and coordinative variability for the Hip-Lower Lumbar and Lower Lumbar-Upper Lumbar joint pairs were quantified using mean absolute relative phase and deviation phase (continuous relative phase), and coupling angle and coupling angle variability (vector coding), respectively. T-tests examined group differences in coordination and variability. Cohen's d bootstrapping analyses identified the more sensitive technique for detecting group differences. Less in-phase and more variable behavior was observed in the low back pain group, mostly independent of joint pair and analytical technique (P < 0.05, Cohen's d range = 0.61 to 1.33). Qualitatively, the low back group limited motion at the lower lumbar spine during lifting/lowering. Continuous relative phase was more sensitive in detecting group differences in coordinative variability, while vector coding was more sensitive towards differences in coordination. These procedures convey distinct information and have their respective merits. Researchers should consider the choice of analytical techniques based on their study objectives.

Asunto(s)

RESUMEN

Walking requires precise movement between body segments, referred to as intersegmental coordination, which is an important factor in efficient motor performance. For children with cerebral palsy (CP), who often demonstrate an impaired neuromuscular system, intersegmental coordination has been shown to be different when compared to their typically developed (TD) peers. However, how intersegmental coordination changes over time in these children is unclear. The aim of this study was to quantify age-related changes in intersegmental coordination in children with bilateral CP without a history of surgical intervention and to compare to control groups of children with TD of similar age, weight, and height. A retrospective analysis of 162 children with bilateral CP who had a baseline and follow-up 3D gait assessment, and no history of surgical intervention, was conducted. Two age, weight, and height control groups of children with TD were included. A full 3-dimensional kinematic analysis was performed, and continuous relative phase analysis of the thigh-shank and shank-foot, while walking at a self-selected walking speed, was used to measure intersegmental coordination. Differences were present for children with CP compared to children with TD at baseline for thigh-shank intersegmental coordination. However, children with CP demonstrated a change over time with a move towards TD patterns at follow-up assessment. This study provides insights into the acquisition and stabilisation of intersegmental coordination between children with CP and TD.

Asunto(s)

RESUMEN

Purpose: Coordination in ice hockey skating has been minimally investigated, particularly in females. The objective was to compare lower-extremity inter-segment coordination of collegiate male and female ice hockey players during forward skating starts. Methods: 3D kinematic data were collected on collegiate male (n = 9) and female (n = 10) participants during accelerative steps. Continuous relative phase (CRP) was calculated for shank-sagittal/thigh-sagittal, shank-sagittal/thigh-frontal, and foot-sagittal/shank-sagittal segment pairs across 2.5 strides on each side. Principal component analysis (PCA) extracted features of greatest variability of the CRP and relationships between principal components and sex were investigated using hierarchical linear model. Results: Males demonstrated more out-of-phase coordination (higher CRP) for side one (p = .01) and side two (p < .01) shank-sagittal/thigh-sagittal as well as side one shank-sagittal/thigh-frontal (p < .01) segment pairs throughout each step. Females demonstrated a greater change in CRP from late stance/early swing to late swing/early stance on side two for shank-sagittal/thigh-frontal segments (p < .01). For side two shank-sagittal/thigh-frontal segments, faster males utilized more out-of-phase coordination throughout each step whereas faster females utilized more in-phase coordination (p < .01). Conclusion: Males and females may employ different coordinative strategies to achieve faster skating speeds. Males tend to utilize more out-of-phase coordination of the shank and thigh throughout strides, although coordinative differences of the shank and foot were not found between sexes. Further investigation is needed to examine the relationship between lower limb strength and coordination as well as the effect of targeted training protocols on lower extremity coordinative patterns.

RESUMEN

BACKGROUND: Low back pain (LBP) is more prevalent in patients with transfemoral amputation using socket prostheses than able-bodied individuals, in part due to altered spinal loading caused by aberrant lumbopelvic movement patterns. Early evidence surrounding bone-anchored limb functional outcomes is promising, yet it remains unknown if this novel prosthesis influences LBP or movement patterns known to increase its risk. RESEARCH QUESTION: How are self-reported measures of LBP and lumbopelvic movement coordination patterns altered when using a unilateral transfemoral bone-anchored limb compared to a socket prosthesis? METHODS: Fourteen patients with unilateral transfemoral amputation scheduled to undergo intramedullary hardware implantation for bone-anchored limbs due to failed socket use were enrolled in this longitudinal observational cohort study (7 F/7 M, Age: 50.2±12.0 years). The modified Oswestry Disability Index (mODI) (self-reported questionnaire) and whole-body motion capture during overground walking were collected before (with socket prosthesis) and 12-months following bone-anchored limb implantation. Lumbopelvic total range of motion (ROM) and continuous relative phase (CRP) segment angles were calculated during 10 bilateral gait cycles. mODI, total ROM, CRP and CRP variabilities were compared between time points. RESULTS: mODI scores were significantly reduced 12-months after intramedullary hardware implantation for the bone-anchored limb (P = 0.013). Sagittal plane trunk and pelvis total ROM during gait were reduced after implantation (P = 0.001 and P < 0.001, respectively). CRP values were increased (more anti-phase) in the sagittal plane during single limb stance and reduced (more in-phase) in the transverse plane during pre-swing of the amputated limb gait cycle (P << 0.001 and P = 0.029, respectively). No differences in CRP values were found in the frontal plane. SIGNIFICANCE: Decreases in mODI scores and lumbopelvic ROM, paired with the changes in lumbopelvic coordination, indicate that bone-anchored limbs may reduce LBP symptoms and reduce compensatory movement patterns for people with unilateral transfemoral amputation.

Asunto(s)

RESUMEN

Background: Despite the existing evidence indicating altered hip kinematics as well as the studies showing altered movement coordination variability in persons with patellofemoral pain (PFP), there is no study investigating the correlation between hip joint kinematic and movement coordination variability in persons with patellofemoral pain (PFP). Objective: This study aims to evaluate the correlation between peak hip adduction and variability of thigh frontal-shank transverse coordination during running in persons with PFP. Material and Methods: In this cross-sectional correlational study, kinematic data were collected from 34 females (17 with and 17 without PFP) aged 18-35 years during treadmill running at preferred and fixed speeds, each for 30 s. The continuous relative phase method was used to calculate the coordination of thigh frontal-shank transverse. To calculate the deviation phase as the variability of intersegmental coordination, the standard deviation of the ensemble continuous relative phase curve points was averaged. The parameters of interest were peak hip adduction and coordination variability of thigh frontal-shank transverse. The Pearson Correlation Coefficient (r) was used to calculate the correlation between the variables. Results: The Pearson correlation coefficient showed a significant negative correlation between the peak hip adduction angle and variability of thigh frontal- shank transverse during running at both fixed (r=-0.553, P<0.05) and preferred (r=-0.660, P<0.01) speeds in persons with PFP while the control group showed a small nonsignificant correlation (r<0.29, P>0.05). Conclusion: The results indicated that greater adduction of the hip joint in persons with PFP during running is contributed to lesser variability of thigh frontal-shank transverse.

RESUMEN

The emergence of optical chirality in the light emitted from plasmonic nanostructures is commonly associated with their geometrical chirality. Although it has been demonstrated that even achiral structures can exhibit chiral near-fields, the existence of chiroptical far-field responses of such structures is widely neglected. In this paper, we present a detailed analysis of the polarization state in a single planar achiral plasmonic nanostructure that sustains more than one prominent plasmon mode. In consideration of the relative phase, the superposition of the fields associated with these modes determines the polarization state of the emitted light in the far-field. Supported by simulations of the surface charge distribution of the particle, we show that the polarization state of the emitted light is already determined in the near-field. The chiroptical far-field responses are analyzed by polarized single-particle dark-field scattering spectroscopy. We introduce an analytical model that enables us to obtain the polarization information from the spectra of structures with dipolar resonances taken under unpolarized illumination. The same principle is confirmed in polarimetric spectroscopy measurements on rhomboids with systematically varied angles, therefore, introducing increasing values of geometrical chirality to the structures. The agreement between the calculation and measurement demonstrates the general validity of our model for both chiral and achiral structures.

RESUMEN

The Lokomat provides task-oriented therapy for patients with gait disorders. This robotic technology drives the lower limbs in the sagittal plane. However, normative gait also involves motions in the coronal and transverse planes. This study aimed to compare the Lokomat with Treadmill gait through three-dimensional (3D)-joint kinematics and inter-joint coordination. Lower limb kinematics was recorded in 18 healthy participants who walked at 3 km/h on a Treadmill or in a Lokomat with nine combinations of Guidance (30%, 50%, 70%) and bodyweight support (30%, 50%, 70%). Compared to the Treadmill, the Lokomat altered pelvic rotation, decreased pelvis obliquity and hip adduction, and increased ankle rotation. Moreover, the Lokomat resulted in significantly slower velocity at the hip, knee, and ankle flexion compared to the treadmill condition. Moderate to strong correlations were observed between the Treadmill and Lokomat conditions in terms of inter-joint coordination between hip-knee (r = 0.67-0.91), hip-ankle (r = 0.66-0.85), and knee-ankle (r = 0.90-0.95). This study showed that some gait determinants, such as pelvis obliquity, rotation, and hip adduction, are altered when walking with Lokomat in comparison to a Treadmill. Kinematic deviations induced by the Lokomat were most prominent at high levels of bodyweight support. Interestingly, different levels of Guidance did not affect gait kinematics. The present results can help therapists to adequately select settings during Lokomat therapy.

Asunto(s)

RESUMEN

In contrast to traditional phase-shifting (PS) algorithms, which rely on capturing multiple fringe patterns with different phase shifts, digital PS algorithms provide a competitive alternative to relative phase retrieval, which achieves improved efficiency since only one pattern is required for multiple PS pattern generation. Recent deep learning-based algorithms further enhance the retrieved phase quality of complex surfaces with discontinuity, achieving state-of-the-art performance. However, since much attention has been paid to understanding image intensity mapping, such as supervision via fringe intensity loss, global temporal dependency between patterns is often ignored, which leaves room for further improvement. In this paper, we propose a deep learning model-based digital PS algorithm, termed PSNet. A loss combining both local and global temporal information among the generated fringe patterns has been constructed, which forces the model to learn inter-frame dependency between adjacent patterns, and hence leads to the improved accuracy of PS pattern generation and the associated phase retrieval. Both simulation and real-world experimental results have demonstrated the efficacy and improvement of the proposed algorithm against the state of the art.

RESUMEN

BACKGROUND: Unilateral lower limb amputees have asymmetrical gaits, particularly on irregular surfaces and slopes. It is unclear how coordination between arms and legs can adapt during cross-slope walking. RESEARCH QUESTION: How do transfemoral amputees (TFAs) adapt their upper-lower limb coordination on cross-slope surfaces? METHODS: Twenty TFA and 20 healthy adults (Ctrl) performed a three-dimensional gait analysis in 2 walking conditions: level ground and cross-slope with prosthesis uphill. Sagittal joint angles and velocities of hips and shoulders were calculated. Continuous relative phases (CRP) were computed between the shoulder and the hip of the opposite side. The closer to 0 the CRP is, the more coordinated the joints are. Curve analysis were conducted using SPM. RESULTS: The mean CRP between the downhill shoulder and the uphill hip was higher in TFA compared to Ctrl (p = 0.02), with a walking conditions effect (p = 0.005). TFA showed significant differences about the end of the stance phase (p = 0.01) between level ground and cross-slope, while Ctrl showed a significant difference (p = 0.008) between these walking conditions at the end of the swing phase. In CRP between the uphill shoulder and the downhill hip, SnPM analysis showed intergroup differences during the stance phase (p < 0.05), but not in the comparison between walking conditions in TFA and Ctrl groups. SIGNIFICANCE: TFA showed an asymmetrical coordination in level ground walking compared to Ctrl. Walking on cross-slope led to upper-lower limb coordination adaptations: this condition impacted the CRP between downhill shoulder and uphill hip in both groups. The management of the prosthetic limb, positioned uphill, induced a reorganization of the coordination with the upper limb of the amputated side. Identifying upper-lower limb coordination adaptations on cross-slope surfaces will help to achieve rehabilitation goals for effective walking in urban environments.

Asunto(s)

RESUMEN

This paper proposes a novel 8-18 GHz 90° switched T-type phase shifter (TPS). In contrast to the conventional TPS, the proposed TPS adds a compensation capacitance to greatly enhance the phase shifting capacity. Moreover, the designed structure also integrates a filtering compensation network, which can effectively achieve a flat relative phase shift in a wide band. The proposed 90° TPS is fabricated using 0.15 µm GaAs pHEMT technology. The TPS achieves homogeneous phase shift at 8-18 GHz, with the measured phase error of less than ±1.5°. The insertion loss of the proposed phase shifter is 1.3-2.6 dB, and the chip size is merely 0.53 × 0.86 mm2. Thanks to these excellent performance characteristics, the designed phase shifter is well-suited for ultra-wideband wireless communication and radar systems.

RESUMEN

Deficits in movement patterns during cutting while running might place soccer players at risk of injury. The objective was to compare joint angles and intersegment coordination between sexes and ages during an unanticipated side-step cutting task in soccer players. This cross-sectional study recruited 11 male (four adolescents and seven adults) and 10 female (six adolescents and four adults) soccer players. Three-dimensional motion capture was used to measure lower-extremity joint and segment angles as participants performed an unanticipated cutting task. Hierarchical linear models examined relationships between joint angle characteristics with age and sex. Continuous relative phase was used to quantify intersegment coordination amplitude and variability. These values were compared between age and sex groups using analysis of covariance. Adult males had greater hip flexion angle excursions than adolescent males, while adult females had smaller excursions than adolescent females (p = .011). Females had smaller changes in hip flexion angles (p = .045), greater hip adduction angles (p = .043), and greater ankle eversion angles (p = .009) than males. Adolescents had greater hip internal rotation (p = .044) and knee flexion (p = .033) angles than adults, but smaller changes in knee flexion angles at precontact compared with stance/foot off (p < .001). For intersegment coordination, females were more out-of-phase than males in the foot/shank segment in the sagittal plane. There were no differences in intersegment coordination variability between groups. Differences in joint motion during an unanticipated cutting task were present between age groups and sexes. Injury prevention programs or training programs may be able target specific deficits to lower injury risk and improve performance.

Asunto(s)

RESUMEN

Purpose: This study aimed to investigate the lower limb inter-joint coordination and variability during Tai Chi movements compared with normal walking in older adults. Methods: A total of 30 female Tai Chi practitioners (70.9 ± 5.2 years) were recruited in this study. Herein, each participant performed three trials of the normal walking and Tai Chi movements. The lower limb kinematics data were collected with Vicon 3D motion capture system. The continuous relative phase (CRP) includes both spatial and temporal information of two adjacent joints, which was calculated to assess the inter-joint coordination of lower limbs. Coordination amplitude and coordination variability were assessed with mean absolute relative phase (MARP) and deviation phase (DP). MANOVOA was used to analyze inter-joint coordination parameters between different movements. Results: The CRP values of hip-knee and knee-ankle segments in the sagittal plane of the Tai Chi movements changed frequently. The MARP values of the hip-knee (p < 0.001) and knee-ankle segments (p = 0.032) as well as the DP values of the hip-knee segment (p < 0.001) were significantly lower in Tai Chi than in normal walking. Conclusion: More consistent and stable inter-joint coordination patterns of Tai Chi movements found in this study may be one of the critical factors that Tai Chi could be a suitable coordinated exercise for older adults.

RESUMEN

BACKGROUND: Previous work has shown that the mean continuous relative phase and coordination variability of lower limbs are modified in older adults when walking. RESEARCH QUESTION: Here, we propose to understand the extent to which such control mechanisms for upper limbs are present during gait. Specifically, we seek to understand if aging and gait speed constraints influence the interjoint control of upper limbs during walking. METHODS: This observational study evaluated thirty-three participants, divided into older (n = 20, age 66.4 ± 4.3 years; mass: 77.2 ± 14.2 kg; height: 165 ± 9.20 cm) and young adults (n = 13, age 29.5 ± 4.7 years; mass 75.5 ± 9.6 kg; height: 172 ± 6.24 cm) were asked to walk at 0.28, 0.83, 1.38 m.s-1 on a level treadmill while their segmental movements were simultaneously registered with 3D motion capture system. We calculated the mean continuous relative phase and coordination variability (continuous relative phase variability) in elbow-shoulder and shoulder-hip pairs, and a generalized estimating equation was used to test the main and interaction effects of age and speed. RESULTS: Older adults had a reduced continuous relative phase (more in-phase coordination) of upper limbs at whole stance for elbow-shoulder, at loading response for shoulder-hip, at mid-stance and terminal stance for elbow-shoulder and shoulder-hip in comparison to young adults at different speeds (p < 0.05). The coordination variability of upper limbs was greater (higher continuous relative phase variability) in older than young adults at 0.28 and 1.38 m.s-1. SIGNIFICANCE: These findings substantiate the altered motor control role of upper limbs in gait aging, suggesting that lower self-selected speed may be related to the reduced ability to control arm movement during the intermediate phases of gait.

Asunto(s)

RESUMEN

Auditory perception can benefit from stimuli in non-auditory sensory modalities, as for example in lip-reading. Compared with such visual influences, tactile influences are still poorly understood. It has been shown that single tactile pulses can enhance the perception of auditory stimuli depending on their relative timing, but whether and how such brief auditory enhancements can be stretched in time with more sustained, phase-specific periodic tactile stimulation is still unclear. To address this question, we presented tactile stimulation that fluctuated coherently and continuously at 4 Hz with an auditory noise (either in-phase or anti-phase) and assessed its effect on the cortical processing and perception of an auditory signal embedded in that noise. Scalp-electroencephalography recordings revealed an enhancing effect of in-phase tactile stimulation on cortical responses phase-locked to the noise and a suppressive effect of anti-phase tactile stimulation on responses evoked by the auditory signal. Although these effects appeared to follow well-known principles of multisensory integration of discrete audio-tactile events, they were not accompanied by corresponding effects on behavioral measures of auditory signal perception. Our results indicate that continuous periodic tactile stimulation can enhance cortical processing of acoustically-induced fluctuations and mask cortical responses to an ongoing auditory signal. They further suggest that such sustained cortical effects can be insufficient for inducing sustained bottom-up auditory benefits.

Asunto(s)

RESUMEN

Understanding the sprinting patterns of individuals with unilateral transfemoral amputation (uTFA) is important for designing improved running-specific prostheses and for prosthetic gait rehabilitation. Continuous relative phase (CRP) analysis acquires clues from movement kinematics and obtains insights into the sprinting coordination of individuals with uTFA. Seven individuals with uTFA sprinted on a 40 m runway. The spatio-temporal parameters, joint and segment angles of the lower limbs were obtained, and CRP analysis was performed on thigh-shank and shank-foot couplings. Subsequently, the asymmetry ratios of the parameters were calculated. Statistical analyses were performed between the lower limbs. Significant differences in the stance time, stance phase percentage, ankle joint angles and CRP of the shank-foot coupling (p < 0.05) were observed between the lower limbs. The primary contributor to these differences could be the structural differences between the lower limbs. Despite the presence of different coordination features in the stance and swing phases between the lower limbs, no significant difference in the coordination patterns of the thigh-shank coupling was observed. This may be a compensation strategy for achieving coordination patterns with improved symmetry between the lower limbs. The results of this study provide novel insights into the sprinting movement patterns of individuals with uTFA.

RESUMEN

In- and antiphase are the dominant patterns identified in the study of synchrony in relative phases. Many previous studies have focused on in-phase synchrony and compared it to asynchrony, but antiphase synchrony has yet not been the subject of much research attention. The limited findings on antiphase synchrony suggest that its role or nature is unclear or unstable in human interaction. To account for this factor, this study examined the possibility that antiphase synchrony simultaneously induced perceived entitativity and uniqueness. The results of an experiment employing a joint hand-clapping task supported this prediction. Further, the elevated feeling of uniqueness in those who experienced antiphase synchrony may have increased the self-other overlap for those who felt oneness with their partner, but it decreased overlap for those who did not. The theoretical implications for synchrony literature are discussed.

RESUMEN

BACKGROUND: Kinesio taping can effectively strengthen weakened muscles, increase walking speed, and improve dynamic balance in hemiplegic patients, but its effect on lower-limb coordination is not clear. Improving lower-limb coordination in hemiplegic patients can decrease risk of fall during walking. RESEARCH QUESTION: This study utilized continuous relative phase to depict the pattern and variability of lower-limb coordination in hemiplegic patients and healthy subjects during walking, and investigate whether it has the acute effect of Kinesio Taping on lower-limb coordination in hemiplegic patients during walking. METHODS: Gait was measured by a three-dimensional motion capture system for 29 hemiplegic patients (KT group) and 15 healthy subjects (control group). Mean continuous relative phase (MCRP) and mean continuous relative phase variability (MCRPV) were calculated to describe and evaluate lower-limb coordination. RESULTS: KT intervention only changed the coordination between the bilateral ankle joints in hemiplegic patients. Before the intervention, the MCRP of the two ankles (AA-MCRP) in the stance period of the control group was greater than the KT group (P < 0.001), the MCRPV of the two ankles (AA-MCRPV) in the swing period was lower than that in KT group (P < 0.001). After the intervention, the AA-MCRP in the stance period of the KT group increased (P < 0.001), the AA-MRPV in the swing period of KT group significantly decreased (P = 0.001). SIGNIFICANCE: Immediate ankle KT intervention can result in the in-phase or anti-phase coordination between the two ankles developing to out-of-phase coordination during the stance period of the affected limb during walking, and increase the stability of the out-of-phase coordination between the two ankles during the swing period of the affected limb. KT can be used in rehabilitation treatment for hemiplegic patients to improve acute coordination between the patients' ankles.

Asunto(s)

RESUMEN

BACKGROUND: Load carriage is a fundamental requirement for military personnel that commonly results in lower-limb injuries. Coupling variability represents a potential injury mechanism for such repetitive tasks and its unknown whether external loads and biological sex affect coupling variability during load carriage. RESEARCH QUESTION: Is there a sex-by-load interaction during load carriage at self-selected walking speeds? METHODS: Twenty-six participants (13 males, 13 females) completed three 10-minute treadmill-based trials wearing body-borne external load (0 %BM, 20 %BM, and 40 %BM) at load-specific self-selected walking speeds. A Vicon motion capture system tracked markers with a lower-body direct-kinematic model calculating sagittal-plane segment kinematics of the thigh, shank, and foot across 19 strides. Continuous relative phase standard deviation (CRPv) provided a measure of coupling variability for each coupling angle (Thigh-Shank and Shank-Foot). The CRPv for each load and sex was compared using statistical parametric mapping repeated measures ANOVA and paired t tests. RESULTS: Significant sex-by-load interactions were reported for the Thigh-Shank coupling. Males demonstrated no significant load differences in CRPv, however, females displayed significantly higher CRPv in the 40 %BM than the 0 %BM condition. A significant main effect of load was observed in the Shank-Foot coupling, with the 40 %BM having significantly greater CRPv than the other load conditions. SIGNIFICANCE: Both biological sex and external loads significantly affected CRPv during load carriage at self-selected walking speeds. Females demonstrated greater CRPv at the heavier loads, suggesting that the perturbation from the heavier mass increases coupling variability, which may also be amplified by a greater total passive load due to their relatively higher adipose tissue compared to males. The consistent CRPv in males suggests that higher relative loads may be required to change coupling variability. Collectively, these results suggest that external load affects the coupling variability of males and females differently, providing potential for injury screening and monitoring programs.

Asunto(s)

RESUMEN

The first complete upper and lower limbswimming cycle after the underwater segment of start and turns represents the breakout phase in competitive swimming. The aim of the present research was to examine the effect of the breakout movements on the stroking variables and coordinative patterns of competitive swimmers. Thirty-three national-level male swimmers performed 4 x 25 m maximal efforts (one of each stroke in random order) from a push start and were recorded by two sequential cameras in the sagittal plane. The average velocity, stroke length, and stroke frequency; the relative duration (%) of the stroke phases; and the inter-limb discrete relative phases were calculated using direct linear transformation algorithms for the breakout and free-swimming phases. In general terms, swimming velocity during breakout was faster (δ 0.27 ± 0.04 m/s, p < 0.001, ES = 0.33) than free swimming (in all strokes but breaststroke), not because of a faster previous underwater kicking or a modified coordinative swimming pattern, but because of an increase in the stroke rate (δ 4.68 ± 0.79 cycles/min, p < 0.001, ES = 0.36). These results indicate how swimmers manage the changing constraints during breakout from underwater to surface swimming.

Asunto(s)

RESUMEN

Humans, like many other animals, live in groups and coordinate actions with others in social settings.1 Such interpersonal coordination may emerge unconsciously and when the goal is not the coordination of movements, as when falling into the same rhythm when walking together.2 Although one of our closest living relatives, the chimpanzee (Pan troglodytes), shows the ability to succeed in complex joint action tasks where coordination is the goal,3 little is known about simpler forms of joint action. Here, we examine whether chimpanzees spontaneously synchronize their actions with conspecifics while walking together. We collected data on individual walking behavior of two groups of chimpanzees under semi-natural conditions. In addition, we assessed social relationships to investigate potential effects on the strength of coordination. When walking with a conspecific, individuals walked faster than when alone. The relative phase was symmetrically distributed around 0° with the highest frequencies around 0, indicating a tendency to coordinate actions. Further, coordination was stronger when walking with a partner compared with two individuals walking independently. Although the inter-limb entrainment was more pronounced between individuals of similar age as a proxy for height, it was not affected by the kinship or bonding status of the walkers or the behaviors they engaged in immediately after the walk. We conclude that chimpanzees adapt their individual behavior to temporally coordinate actions with others, which might provide a basis for engaging in other more complex forms of joint action. This spontaneous form of inter-individual coordination, often called entrainment, is thus shared with humans.

Asunto(s)