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Aims: Low intra-abdominal pressure (IAP) and high perineal pressure (PP) are safe conditions for pelvic floor. This study aims to measure IAP and PP in Beninese post-partum women during abdominal exercises and determine what exercise presents less risk for pelvic floor after delivery., Methods: IAP and PP were measured at rest and during exercises performed in random order: Cough, pelvic floor contraction (PFC), Curl-up, diaphragmatic aspiration (DA), Drawing-in, DA + Curl-up and Drawing-in+Curl-up, using a Micro-Full biofeedback PHENIX-Vivaltis with dual-channel probe. Results were presented as change from rest (maximal value during exercise minus value at rest) and expressed in percentage of this change for the reference exercise, Cough for IAP and PFC for PP. The ANOVA repeated measures test was used to compare pressures between exercises., Results: Seventeen postpartum women participated to this study. The maximal IAP and PP change were the highest (100%), respectively, during cough and PFC. During DA, IAP was the lowest (-7%) and PP was 51%. During Curl-up, IAP was moderate (43%) and significantly higher than during PFC (33%), Drawing-in (16%) and DA. PP was low (29%) and similar to that during Drawing-in (23%). Compared to Curl-up, Drawing-in+Curl-up increased PP (50%) but did not decrease IAP (40%). DA + Curl-up increased PP (58%) and decreased IAP (31%) compared to Curl-up but not compared to DA., Conclusion: DA is safe and Curl-up presents little risk for the pelvic floor. According to interindividual variations observed in IAP and PP, intrinsic factors should be considered in future studies., (© 2022 Wiley Periodicals LLC.)

Background: Diastasis recti is diagnosed when the interrecti distance (IRD) is larger than a threshold value. Published thresholds were measured at rest with ultrasound while in Benin physiotherapists use calipers during abdominal contraction., Objectives: The aim was to define IRD threshold values measured with calipers in Beninese participants in order to diagnose diastasis recti in a clinical environment and identify women needing abdominal rehabilitation., Method: Interrecti distance was measured using ultrasound and calipers. Linea alba stiffness was assessed by palpation, abdominal strength and endurance by manual testing. In men and nulliparous women, IRD threshold values were defined as IRD P90. In postpartum women, IRD P80 and a threshold defined with a receiver operating characteristics (ROC) curve based on linea alba stiffness were used. In these women, abdominal strength and endurance were compared depending on IRD threshold and linea alba stiffness with a Mann Whitney test., Results: In 391 Beninese participants, the IRD threshold measured with calipers was 17 mm in men, 15 mm in nulliparous and 18 mm (15 mm with ROC curve) in postpartum women. Postpartum women with an IRD above 18 mm had significantly lower abdominal strength. Those with a slack linea alba had significantly lower abdominal strength and endurance., Conclusion: The defined IRD threshold values can be used in a Beninese clinical environment. Future studies should confirm whether they can be applied to other African populations., Clinical Implications: Abdominal rehabilitation should be recommended to postpartum women whose IRD is above the threshold values but also in cases of slack linea alba and poor abdominal function., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article., (© 2022. The Authors.)

In humans, enhanced joint range of motion is observed after static stretch training and results either from an increased stretch tolerance or from a change in the biomechanical properties of the muscle-tendon unit. We investigated the effects of an intermittent stretch training on muscle biomechanical and structural variables. The left plantarflexors muscles of seven anesthetized New Zealand (NZ) White rabbits were passively and statically stretched three times a week for 4 wk, while the corresponding right muscles were used as nonstretched contralateral controls. Before and after the stretching protocol, passive torque produced by the left plantarflexor muscles as a function of the ankle angle was measured. The left and right plantarflexor muscles were harvested from dead rabbits and used to quantify possible changes in muscle structure. Significant mass and serial sarcomere number increases were observed in the stretched soleus but not in the plantaris or medial gastrocnemius. This difference in adaptation between the plantarflexors is thought to be the result of their different fiber type composition and pennation angles. Neither titin isoform nor collagen amount was modified in the stretched compared with the control soleus muscle. Passive torque developed during ankle dorsiflexion was not modified after the stretch training on average, but was decreased in five of the seven experimental rabbits. Thus, an intermittent stretching program similar to those used in humans can produce a change in the muscle structure of NZ White rabbits, which was associated in some rabbits with a change in the biomechanical properties of the muscle-tendon unit., (Copyright © 2015 the American Physiological Society.)

The purpose of this study was to mechanically evoke a triceps surae stretch reflex during the swing phase of running, to study its within-the-step phase dependency. Seven participants ran on a treadmill at 2.8 m·s-1 wearing an exoskeleton capable of evoking a sudden ankle dorsiflexion. We measured the electromyographic activity of the soleus, medial and lateral gastrocnemii just after the perturbation to evaluate the triceps surae stretch reflex. Similar perturbations were also delivered at rest. Our results showed that the stretch reflex was suppressed during the swing phase of running, except in late swing where a late reflex response was observed. At rest, all triceps surae muscles showed an early reflex response to stretch. Our findings suggest that the triceps surae short/medium-latency stretch reflex cannot be evoked during swing phase and thus cannot contribute to the control of the locomotor pattern after aperturbation during this phase.

In this study we investigated the effect of a mechanical perturbation of unexpected timing during human running. With the use of a powered exoskeleton, we evoked a dorsiflexion of the right ankle during its swing phase while subjects ran on a treadmill. The perturbation resulted in an increase of the right ankle dorsiflexion of at least 5°. The first two as well as the next five steps after the perturbation were analyzed to observe the possible immediate and late biomechanical adjustments. In all cases subjects continued to run after the perturbation. The immediate adjustments were the greatest and the most frequent when the delay between the right ankle perturbation and the subsequent right foot touch-down was the shortest. For example, the vertical impact peak force was strongly modified on the first step after the perturbations and this adjustment was correlated to a right ankle angle still clearly modified at touch-down. Some late adjustments were observed in the subsequent steps predominantly occurring during left steps. Subjects maintained the step length and the step period as constant as possible by adjusting other step parameters in order to avoid stumbling and continue running at the speed imposed by the treadmill. To our knowledge, our experiments are the first to investigate perturbations of unexpected timing during human running. The results show that humans have a time-dependent, adapted strategy to maintain their running pattern., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The goal of the present study was to determine the relative efficacy of verbal and auditory knowledge of results for promoting learning of a new constrained relative timing pattern. In a series of four experiments we compared the efficiency of verbal knowledge of results to that of auditory knowledge of results. The results of all four experiments revealed that verbal knowledge of result is a very effective source of information to promote learning of a new imposed relative timing pattern. Auditory knowledge of results favoured learning of a new relative timing pattern in a very limited set of circumstances. In the present study, this was only the case when movement velocity remained constant from one segment of the task to the next and if it resulted in an unfamiliar temporal pattern. The results of all four experiments also provided evidence that movement parameterization and relative timing are independent processes that can be developed in parallel.