Article

Postural and respiratory activation of the trunk muscles changes with mode and speed of locomotion

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Abstract

Despite the importance of the deep intrinsic spinal muscles for trunk control, few studies have investigated their activity during human locomotion or how this may change with speed and mode of locomotion. Furthermore, it has not been determined whether the postural and respiratory functions, of which these muscles take part, can be coordinated when locomotor demands are increased. EMG recordings of abdominal and paraspinal muscles were made in seven healthy subjects using fine-wire and surface electrodes. Measurements were also made of respiration and gait parameters. Recordings were made for 10s as subjects walked on a treadmill at 1 and 2 ms(-1) and ran at 2, 3, 4 and 5 ms(-1). Unlike the superficial muscles, transversus abdominis was active tonically throughout the gait cycle with all tasks, except running at speeds of 3 ms(-1) and greater. All other muscles were recruited in a phasic manner. The relative duration of these bursts of activity was influenced by speed and/or mode of locomotion. Activity of all abdominal muscles, except rectus abdominis (RA), was modulated both for respiration and locomotor-related functions but this activity was affected by the speed and mode of locomotion. This study provides evidence that the deep abdominal muscles are controlled independently of the other trunk muscles. Furthermore, the pattern of recruitment of the trunk muscles and their respiratory and postural coordination is dependent on the speed and mode of locomotion.

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... The observation of less variation in LM EMG amplitude (lower peaks, greater minima) during FRED exercise than walking is likely to be explained by the absence of ground impacts at foot contact in FRED, which are known to lead to high peaks of LM activation in walking (Saunders et al. 2004b). It follows that there would be less difference in the pattern of TrA between FRED and walking as activation of that muscle is less dominated by peaks at foot contact in walking (Saunders et al. 2004b). ...
... The observation of less variation in LM EMG amplitude (lower peaks, greater minima) during FRED exercise than walking is likely to be explained by the absence of ground impacts at foot contact in FRED, which are known to lead to high peaks of LM activation in walking (Saunders et al. 2004b). It follows that there would be less difference in the pattern of TrA between FRED and walking as activation of that muscle is less dominated by peaks at foot contact in walking (Saunders et al. 2004b). ...
... Second, as mentioned above, FRED exercise lacks high ground reaction forces at foot strike. As activation of many of the trunk muscles is associated with foot strike (Saunders et al. 2004b) this would tend to constrain the variation between cycles, leading to a higher coefficient of variation. ...
Article
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Gravitational unloading leads to adaptations of the human body, including the spine and its adjacent structures, making it more vulnerable to injury and pain. The Functional Re-adaptive Exercise Device (FRED) has been developed to activate the deep spinal muscles, lumbar multifidus (LM) and transversus abdominis (TrA), that provide inter-segmental control and spinal protection. The FRED provides an unstable base of support and combines weight bearing in up-right posture with side alternating, elliptical leg movements, without any resistance to movement. The present study investigated the activation of LM, TrA, obliquus externus (OE), obliquus internus (OI), abdominis, and erector spinae (ES) during FRED exercise using intramuscular fine-wire and surface EMG. Nine healthy male volunteers (27 ± 5 years) have been recruited for the study. FRED exercise was compared with treadmill walking. It was confirmed that LM and TrA were continually active during FRED exercise. Compared with walking, FRED exercise resulted in similar mean activation of LM and TrA, less activation of OE, OI, ES, and greater variability of lumbo-pelvic muscle activation patterns between individual FRED/gait cycles. These data suggest that FRED continuously engages LM and TrA, and therefore, has the potential as a stationary exercise device to train these muscles.
... In human, the effects of locomotor mode and those of speed on the pattern of activation of paraspinal muscles can be further studied separately. A transition from walking to running at the same speed produces substantial alterations in the pattern of activity of lumbar back muscles (Cappellini et al., 2006;Saunders et al., 2004Saunders et al., , 2005Thorstensson et al., 1982). Conversely, increases in speed during a given locomotor mode (walking or running) are associated with increases in the intensity and relative duration of muscle activations of paraspinal muscles, and only minor changes in their relative timings (Anders et al., 2007;Cappellini et al., 2006;Saunders et al., 2004Saunders et al., , 2005Thorstensson et al., 1982). ...
... A transition from walking to running at the same speed produces substantial alterations in the pattern of activity of lumbar back muscles (Cappellini et al., 2006;Saunders et al., 2004Saunders et al., , 2005Thorstensson et al., 1982). Conversely, increases in speed during a given locomotor mode (walking or running) are associated with increases in the intensity and relative duration of muscle activations of paraspinal muscles, and only minor changes in their relative timings (Anders et al., 2007;Cappellini et al., 2006;Saunders et al., 2004Saunders et al., , 2005Thorstensson et al., 1982). Interestingly, interindividual variability is larger at low speeds than at high speeds of walking in humans (Ivanenko et al., 2009). ...
... Previous studies have demonstrated that some hypaxial muscles are phasically activated during locomotion in humans (Anders et al., 2007;Cappellini et al., 2006;Saunders et al., 2004;Waters and Morris, 1972) and dogs (Carrier, 1996;Deban and Carrier, 2002;Fife et al., 2001). However, the role of the hypaxial musculature during stepping in mammals remains poorly understood. ...
Article
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Much of what we know about the flexibility of the locomotor networks in vertebrates is derived from studies examining the adaptation of limb movements during stepping in various conditions. However, the body movements play important roles during locomotion: they produce the thrust during undulatory locomotion and they help to increase the stride length during legged locomotion. In this chapter, we review our current knowledge about the flexibility in the neuronal circuits controlling the body musculature during locomotion. We focus especially on salamander because, as an amphibian, this animal is able to display a rich repertoire of aquatic and terrestrial locomotor modes.
... Additionally, predictable trunk perturbations are associated with earlier activation of deep versus superficial fascicles of the multifidus (MacDonald et al., 2009;Moseley et al., 2002). Surprisingly, very few studies have investigated either the thoracolumbar spinal posture or paravertebral muscle activity during gait in asymptomatic adults (Lamoth et al., 2004;Lee et al., 2014;Saunders et al., 2004Saunders et al., , 2005Thorstensson et al., 1982), or in adults with back pain (Lamoth et al., 2004(Lamoth et al., , 2006, despite walking being commonly promoted as beneficial in optimising low back health. An improved understanding of the neuromuscular mechanics of the lumbar spine appears necessary to better inform the use of walking as a therapeutic strategy. ...
... However, their methods used surface EMG and the potential cross-talk from erector spinae at the higher lumbar level limits the confidence of their results in promoting variable inclination for differential activation of the paravertebral muscles. Based on a slightly older and predominantly male (six of seven) cohort to examine postural and respiratory trunk muscle activation during walking and running at variable speeds, Saunders et al. (2004) utilised intramuscular EMG to measure activity of the deep and superficial regions of multifidus at L4. Comparing their two walking speed conditions, biphasic activity was shown for both regions at their slow, and triphasic activity at their faster speed, with different timing noted according to foot strike between the multifidus regions. However, despite kinematic adaptations, the authors reported no differential activity within multifidus during walking, but a trend for increased duration of activation and period of activity with faster locomotion speeds progressing from walking to running. ...
... In agreement with our findings, increases in the amplitude and relative duration of superficial abdominal and paravertebral muscles are shown with faster gait speeds (Grillner et al., 1978;Lee et al., 2014;Saunders et al., 2004Saunders et al., , 2005Thorstensson et al., 1982). However, our results indicating longer duration of the deep compared to superficial multifidus with increased walking demand, and the time of peak activity differing with varying inclinations, appears to conflict in part with the study most closely aligned with ours methodologically (Saunders et al., 2004). ...
... Additionally, predictable trunk perturbations are associated with earlier activation of deep versus superficial fascicles of the multifidus (MacDonald et al., 2009; Moseley et al., 2002 ). Surprisingly , very few studies have investigated either the thoracolumbar spinal posture or paravertebral muscle activity during gait in asymptomatic adults (Lamoth et al., 2004; Lee et al., 2014; Saunders et al., 2004 Saunders et al., , 2005 Thorstensson et al., 1982), or in adults with back pain (Lamoth et al., 2004Lamoth et al., , 2006 ), despite walking being commonly promoted as beneficial in optimising low back health. An improved understanding of the neuromuscular mechanics of the lumbar spine appears necessary to better inform the use of walking as a therapeutic strategy. ...
... However, their methods used surface EMG and the potential cross-talk from erector spinae at the higher lumbar level limits the confidence of their results in promoting variable inclination for differential activation of the paravertebral muscles. Based on a slightly older and predominantly male (six of seven) cohort to examine postural and respiratory trunk muscle activation during walking and running at variable speeds, Saunders et al. (2004) utilised intramuscular EMG to measure activity of the deep and superficial regions of multifidus at L4. Comparing their two walking speed conditions, biphasic activity was shown for both regions at their slow, and triphasic activity at their faster speed, with different timing noted according to foot strike between the multifidus regions. However, despite kinematic adaptations, the authors reported no differential activity within multifidus during walking, but a trend for increased duration of activation and period of activity with faster locomotion speeds progressing from walking to running. ...
... As such, our study using intramuscular EMG to record multifidus activity at the lowest lumbar segment during walking might be extended to include multiple thoracolumbar levels to examine activation. In agreement with our findings, increases in the amplitude and relative duration of superficial abdominal and paravertebral muscles are shown with faster gait speeds (Grillner et al., 1978; Lee et al., 2014; Saunders et al., 2004 Saunders et al., , 2005 Thorstensson et al., 1982). However, our results indicating longer duration of the deep compared to superficial multifidus with increased walking demand, and the time of peak activity differing with varying inclinations , appears to conflict in part with the study most closely aligned with ours methodologically (Saunders et al., 2004). ...
Article
Purpose: Lumbar multifidus is a complex muscle with multi-fascicular morphology shown to be differentially controlled in healthy individuals during sagittal-plane motion. The normal behaviour of multifidus muscle regions during walking has only received modest attention in the literature. This study aimed to determine activation patterns for deep and superficial multifidus in young adults during walking at different speeds and inclination. Methods: This observational cohort study evaluated ten healthy volunteers in their twenties (three women, seven men) as they walked on a treadmill in eight conditions; at 2km/h and 4km/h, each at 0, 1, 5, and 10% inclination. Intramuscular EMG was recorded from the deep and superficial multifidus unilaterally at L5. Activity was characterized by: amplitude of the peak of activation, position of peak within the gait cycle (0-100%), and duration relative to the full gait cycle. Results: Across all conditions superficial multifidus showed higher normalised EMG amplitude (p<0.01); superficial multifidus peak amplitude was 232±115% higher when walking at 4km/h/10%, versus only 172±77% higher for deeper region (p<0.01). The percentage of the gait cycle where peak EMG amplitude was detected did not differ between regions (49±13%). Deep multifidus duration of activation was longer when walking at the faster vs slower speed at all inclinations (p<0.01), which was not evident for superficial multifidus (p<0.05). Thus, a significantly longer activation of deep multifidus was observed compared to superficial multifidus when walking at 4km/h (p<0.05). Conclusions: Differential activation within lumbar multifidus was shown in young adults during walking. The prolonged, more tonic activation of deep relative to superficial regions of multifidus during gait supports a postural function of deeper fibres.
... Thus, abdominal muscles are generally regarded as the principal muscles of active expiration. Several studies have investigated the strategies used by the central nervous system (CNS) to adequately coordinate the postural and respiratory functions of abdominal muscles during daily activities [13,14]. From these studies, it seems that: (i) both postural and respiratory functions can be performed simultaneously; and (ii) the CNS seems to be able to prioritize one function over the other if necessary. ...
... Thus, a decreased postural compensation to respiration could be due to changes affecting postural and respiratory activation of the abdominal muscles. Previous studies have shown dual modulation of trunk muscle activity with regard to respiration and posture [14,25]. Based on these studies, a lower contribution to the maintenance of posture by the OE and OI muscles immediately after the cessation of cycling exercise could account for a reduced postural compensation for respiration [2], and thus the greater postural oscillations measured in the present study. ...
... As evidenced by the patterns of muscle activity, the present data suggest that: (i) both postural and respiratory functions can be performed simultaneously; and (ii) the CNS seems able to prioritize one function over the other when respiration increases, suggesting a selective coordination between the rhythmical respiratory drive and the postural drive to the abdominal muscles. This supports the observations reported by Hodges et al. [25], Saunders et al. [14] and more recently by David et al. [3], which showed that different respiratory drives impact postural control differently, at least at the ankle level. Otherwise, if our results reinforce the existence of functional links between respiration and postural control centres, the strategies used by the CNS could also be influenced by the state of functional systems involved in the movement [26]. ...
... For most muscles, these peaks occurred around the start of (heel strike), and midway through the gait cycle (just prior to toe off). This is consistent with previous research that observed peaks in lumbopelvic muscle activity around heel strike and toe off in walking [40]. Saunders et al. [40] observed phasic activity of LM (superficial and deep fibres), ES, IO and EO, where bursts of activity were associated with the need to maintain lumbopelvic stability at heel strike and toe off [41], and the need to absorb impact forces at heel strike [42]. ...
... This is consistent with previous research that observed peaks in lumbopelvic muscle activity around heel strike and toe off in walking [40]. Saunders et al. [40] observed phasic activity of LM (superficial and deep fibres), ES, IO and EO, where bursts of activity were associated with the need to maintain lumbopelvic stability at heel strike and toe off [41], and the need to absorb impact forces at heel strike [42]. ...
... Internal oblique in the present study was active for the majority of the gait cycle during OW, but showed biphasic modulation which has been linked to respiration and changes in trunk motion through the gait cycle [40]. During EX, these peaks in activity were not apparent, suggesting a shift from phasic to tonic activity. ...
Article
The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.
... The rapid arm movement and external trunk perturbation studies performed by Lorimer Differential deep and superficial lumbar multifidus EMG activity has been investigated during gait using different locomotor modes (walk, run) and at different velocities (1, 2, 3, 4, 5mIs) (Saunders et al. 2004;Saunders et al. 2005). Transversus abdominus excitation is relatively tonic throughout the gait cycle, yet superficial and deep lumbar multifidus fibres are phasically excited (Saunders et al. 2004;Saunders et al. 2005). ...
... The rapid arm movement and external trunk perturbation studies performed by Lorimer Differential deep and superficial lumbar multifidus EMG activity has been investigated during gait using different locomotor modes (walk, run) and at different velocities (1, 2, 3, 4, 5mIs) (Saunders et al. 2004;Saunders et al. 2005). Transversus abdominus excitation is relatively tonic throughout the gait cycle, yet superficial and deep lumbar multifidus fibres are phasically excited (Saunders et al. 2004;Saunders et al. 2005). Both superficial and deep lumbar multifidus fibres were modulated by the frequency of motion (Saunders et al. 2004) and there did not appear to be a consistent relationship between deep and superficial fibre excitation onsets (See Figure 4 in Saunders et al. 2004). ...
... Transversus abdominus excitation is relatively tonic throughout the gait cycle, yet superficial and deep lumbar multifidus fibres are phasically excited (Saunders et al. 2004;Saunders et al. 2005). Both superficial and deep lumbar multifidus fibres were modulated by the frequency of motion (Saunders et al. 2004) and there did not appear to be a consistent relationship between deep and superficial fibre excitation onsets (See Figure 4 in Saunders et al. 2004). The total percentage of muscle excitation through the gait cycle increased comparably in erector spinae, deep and superficial lumbar multifidus fibres (Saunders et al. 2004). ...
... The observation of less variation in LM EMG amplitude (lower peaks, greater minima) during FRED exercise than walking is likely to be explained by the absence of ground impacts at foot contact in FRED, which are known to lead to high peaks of LM activation in walking (Saunders et al. 2004b). It follows that there would be less difference in the pattern of TrA between FRED and walking as activation of that muscle is less dominated by peaks at foot contact in walking (Saunders et al. 2004b). ...
... The observation of less variation in LM EMG amplitude (lower peaks, greater minima) during FRED exercise than walking is likely to be explained by the absence of ground impacts at foot contact in FRED, which are known to lead to high peaks of LM activation in walking (Saunders et al. 2004b). It follows that there would be less difference in the pattern of TrA between FRED and walking as activation of that muscle is less dominated by peaks at foot contact in walking (Saunders et al. 2004b). ...
... Second, as mentioned above, FRED exercise lacks high ground reaction forces at foot strike. As activation of many of the trunk muscles is associated with foot strike (Saunders et al. 2004b) this would tend to constrain the variation between cycles, leading to a higher coefficient of variation. ...
... Son çalışmalar, merkezi sinir sistemi tarafından gövde kaslarının postürel ve solunum fonksiyonlarını koordine etmek için kullanıldığının kanıtlarını sunmaktadır. 25 Solunumun koordinasyonu hedef alan bir başka çalışmada ise hızlı tekrarlayan kol hareketleri sırasında transversus abdominis ve diyaframatik kaslar hem hareket hem de solunum sıklığında fazik modülasyon ile tonik aktivasyon gösterdiği belirtilmiştir. 12 Saunders ve ark. ...
... yapmış olduğu araştırma bu ikili fonksiyonun lokomosyon gibi doğal hareketler sırasında da oluştuğunu doğrulamaktadır. 25 Ancak önceki çalışmalardan farklı olarak, Saunders'in çalışmasında obliquus internus ve obliquus externus için ikili postür ve solunum modülasyonu da tanımlanmıştır. Bu, hem postürel hem de solunum fonksiyonlarının fonksiyonel hareketler sırasında lateral abdominaller ile eşzamanlı olarak gerçekleştirilebildiğini ve yürüyüş sırasında lokomotor respiratuar kuplajın daha önceki araştırmalarla uyumlu olduğunu doğrulamaktadır. ...
... 10 Özellikle postürel talep arttıkça merkezi sinir sistemi görevi basitleştirmek ve reaktif kuvvetlerde hız arttıkça ortaya çıkan postürel ihtiyacı karşılamak için solunum ve lokomosyon arasında çeşitli stratejiler kullanmaktadır. 25 Mevcut bilgiler, derin ve yüzeysel abdominal kasların normal fonksiyonlarını düzeltmek için farklı antrenmanların gerekli olduğunu ve antrenmanın yapılacak olan aktivitenin özelliğine ve hızına özel olması gerektiğini öne sürmektedir. ...
Preprint
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Core stabilizasyon terimi son yıllarda sportif performans ve sağlık için egzersiz uzmanlarının ya-kından takip ettikleri, gelişimi ve ilerleme süreçleri için çeşitli stratejiler kullanarak faydalandıkları bir kavram olarak karşımıza çıkmaktadır. Son dönemde birçok araştırmanın ortaya çıkmasıyla muğlak alan-larının daha da üzerine gidilen bu kavram, popülari-tesinin her geçen gün artması nedeniyle daha fazla (21-23 Mayıs 2017, Bursa)'nde sözel olarak sunulmuştur. ÖZET Diyaframın core bölgesi stabilitesindeki önemi, birleşik atletik faaliyetlerde, kuvvet ve hareketi optimum şekilde üretmek, aktarmak ve kontrol etmek için gövdenin pelvis üzerindeki konumunu ve hareketini kontrol etme yeteneğidir. Bu çalışmanın amacı, core bölgesi stabilite-sinde diyafram nefesinin öneminin anlatılması ve iyileştirme stratejile-rinin belirlenmesidir. Panjabi'ye göre, bu bütünlüğü koruyabilmek için, merkezi sinir sistemi (kontrol), iskelet sistemi (pasif) ve kas sistemi (aktif) birlikte çalışır. Bu sistemlerin bir bileşenindeki fonksiyon bo-zukluğunun diğer sistemlerin bunu telafi etmesine, bir veya birden fazla sistemin uzun vadeli adaptasyonuna ve sistemlerin bileşenlerinin zarar görmesine neden olabileceği düşünülmektedir. Bu nedenle, aslında omurganın stabilitesinin sadece kas kuvvetine değil, merkezi sinir sis-temine uygun duyu girdisine bağlı olduğu anlaşılmıştır. Diyaframın eş-zamanlı stabilizasyonda ve solunum sisteminde rolü olması nedeniyle değerlendirme, sırtüstü, yüzüstü, oturarak ve ayakta durmayı içermeli-dir. Değerlendirme sonucunda diyafram nefesinin öğrenilmesi sağlan-malı ve doğru nefes tekniği etkin bir şekilde sahada uygulanacak hareket modellerine adapte edilmelidir. Eğer doğru bir diyafram kulla-nımı sağlanamıyor ise, performans sırasında göğüsten alınan nefes ne-deniyle daha fazla oksijen alma ihtiyacı hissedilecek, bu da çok daha sık nefes alışverişine neden olacak ve sporcunun normalden daha önce yo-rulmasına sebep olabilecektir. Kuvvet ve kondisyon antrenörleri, daha iyi solunum alışkanlıklarının core stabilizasyonunu olumlu olarak et-kileyebileceği ve sporcunun genel kondisyon seviyesinin iyileştirebi-leceği için sporcuların solunum modellerini değerlendirmeyi ve yeniden eğitmeyi düşünmelidir. Anah tar Ke li me ler: Diyafram; core stabilizasyonu; nefes ABS TRACT The importance of the diaphragm in the stability of the core region is the ability to control the position and movement of the trunk on the pelvis in optimal athletic activities to optimally produce, transmit and control force and movement. The aim of this study is to explain the importance of diaphragm breathing in core region stability and to determine improvement strategies. According to Panjabi, the central nervous system (control), the skeletal system (passive) and the muscular system (active) work together to maintain this integrity. It is also contemplated that dysfunction in one component of these systems may cause other systems to compensate for this, long-term adaptation of one or more systems, and damage to the components of the systems. Thus, it has been found that the stability of the spine depends not only on muscle strength but also on sensory input to the central nervous system. Because the diaphragm has a role in simultaneous stabilization and respiratory system, the assessment should include supine, prone, sitting and standing. As a result of the evaluation, the diaphragm breath should be learned and this should be adapted effectively to the movement patterns to be applied in the field. If proper diaphragm use cannot be achieved, there will be a need for more oxygen to breathe from the chest during performance, which will cause more frequent breathing and may cause the athlete to get tired earlier than usual. Strength and conditioning coaches should consider evaluating and retraining their breathing patterns for athletes, as better breathing habits can positively affect core stabilization and ultimately improve the athlete's overall fitness level.
... IAP is generated when the diaphragm descends, creating a simultaneous reflex co-activation of the TrA and the pelvic floor muscles (Hodges et al. 2001). The forced expiratory and inspiratory muscle function and total TIS score may be related because the cocontraction of abdominal muscles contributes to IAP, which is needed to maintain trunk balance (Saunders et al. 2004). These results suggest that stroke patients are likely to have some impairment in forced expiratory and inspiratory muscle function because of the weakening of the abdominal muscles. ...
... These results suggest that stroke patients are likely to have some impairment in forced expiratory and inspiratory muscle function because of the weakening of the abdominal muscles. Thus, functional changes occur in the forced expiratory and inspiratory muscles when trunk balance is needed, and coordination of abdominal muscles activities is required (Hodges and Gandevia 2000b;Saunders et al. 2004). ...
Article
The abdominal muscles play a role in trunk balance. Abdominal muscle thickness is asymmetrical in stroke survivors, who also have decreased respiratory muscle function. We compared the thickness of the abdominal muscles between the affected and less affected sides in stroke survivors. In addition, the relationship between respiratory muscle function and trunk balance was evaluated. Chronic stroke patients (18 men, 15 women; mean age, 58.94 ± 12.30 years; Mini-Mental Status Examination score ≥ 24) who could sit without assist were enrolled. Abdominal muscle thickness during rest and contraction was measured with ultrasonography, and the thickening ratio was calculated. Respiratory muscle function assessment included maximum respiratory pressure, peak flow, and air volume. Trunk function was evaluated using the Trunk Impairment Scale, and trunk balance was estimated based on the center of pressure velocity and path length within the limit of stability in sitting posture. Abdominal muscles were significantly thinner on the affected side, and the thickening ratio was lower in the affected side (P < 0.05). In addition, the higher thickening ratio of the affected side showed significant relationship with higher trunk function. Moreover, higher respiratory muscle function was significantly correlated with higher level of trunk function and balance in stroke patients (P < 0.05). Thus, chronic stroke survivors have decreased abdominal muscle thickness on the affected side, and respiratory muscle function has positive correlation with trunk function and balance. We propose that respiratory muscle training should be included as part of trunk balance training in chronic stroke patients.
... In able-bodied individuals, the trunk muscles are rhythmically activated during walking to maintain upper body steadiness [9,10], and the amplitude of trunk muscle activity increases with increasing gait speed as a result of the higher postural stability demands [11,12]. Robotic exoskeletons, such as the Lokomat® and Ekso™, are used to facilitate gait training for people with SCI [13][14][15][16], but it remains unknown the extent to which they engage those trunk muscles that are normally activated during walking. ...
... Trunk muscle activation patterns are known to alter with walking speed [11,12]. Therefore, walking speed had to be matched between the Lokomat and Ekso to allow for an appropriate comparison. ...
Article
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Background The trunk muscles are critical for postural control. Recent neurophysiological studies have revealed sparing of trunk muscle function in individuals with spinal cord injury (SCI) classified with thoracic or cervical motor-complete injuries. These findings raise the possibility for recruiting and retraining this spared trunk function through rehabilitation. Robotic gait training devices may provide a means to promote trunk muscle activation. Thus, the objective of this study was to characterize and compare the activation of the trunk muscles during walking with two robotic gait training devices (Ekso and Lokomat) in people with high thoracic motor-complete SCI. Methods Participants with chronic motor-complete paraplegia performed 3 speed-matched walking conditions: Lokomat-assisted walking, Ekso-assisted walking overground, and Ekso-assisted walking on a treadmill. Surface electromyography (EMG) signals were recorded bilaterally from the rectus abdominis (RA), external oblique (EO), and erector spinae (ES) muscles. Results Greater recruitment of trunk muscle EMG was elicited with Ekso-assisted walking compared to the Lokomat. Similar levels of trunk EMG activation were observed between Ekso overground and Ekso on the treadmill, indicating that differences between Ekso and Lokomat could not be attributed to the use of a hand-held gait aid. The level of trunk EMG activation during Lokomat walking was not different than that recorded during quiescent supine lying. Conclusions Ekso-assisted walking elicits greater activation of trunk muscles compared to Lokomat-assisted walking, even after controlling for the use of hand-held assistive devices. The requirement of the Ekso for lateral weight-shifting in order to activate each step could lead to better postural muscle activation. Electronic supplementary material The online version of this article (10.1186/s12984-018-0453-0) contains supplementary material, which is available to authorized users.
... Previous work documented 52 additional cellular and synaptic mechanisms underlying inter-circuit regulation during other versions of the gastric mill rhythm Clemens et al., 1998;. Although coordination between different behaviors, such as locomotion and respiration, occurs in many animals (Bramble and Carrier 1983;Syed and Winlow 1991;Kawahara et al., 1989;Saunders et al., 2004), the underlying cellular mechanisms remain to be determined in these other systems. ...
... This observation adds to the previously established, intertwined nature of the gastric mill and pyloric circuits, which exhibit coordinated activity and regulate each others cycle period, despite functioning with mean cycle periods that are ~10-fold different Clemens et al., 1998;Nadim et al., 1998;Bucher et al. 2006). Many complex behaviors involve coordination between separate motor networks, as occurs for example between locomotion and respiration (Kawahara et al., 1989;Syed and Winlow, 1991;Bernasconi and Kohl, 1993;Saunders et al., 2004;Gariépy et al., 2010). Thus far, however, in most of these systems it remains to be determined whether the coordination results from interactions between the two CPGs or is imposed on them from descending and/or ascending inputs (Ezure and Tanaka, 1997;Steriade, 2006). ...
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My thesis aimed to elucidate several aspects of motor circuit regulation and its impact on movement. It is well established that a single motor network can produce different output patterns in response to different inputs. However, in most model systems it remains challenging to identify the neurons comprising these networks and determine their role(s) in network operation, including whether each network neuron retains its role(s) when the network generates different output patterns. Also, most work on these circuits has occurred in the isolated nervous system, so little is known about how muscles respond to distinct neural outputs. I therefore aimed to address the cellular and synaptic mechanisms underlying these unresolved issues using the decapod crustacean stomatogastric nervous system. My work focused on a rhythmically active, network-driven motor circuit (central pattern generator [CPG] circuit) called the gastric mill (chewing) CPG in the crab stomatogastric ganglion. This circuit generates the gastric mill rhythm when activated by modulatory projection neurons (e.g. MCN1, CPN2) located in the commissural ganglia, and it is regulated by identified sensory feedback. I addressed and confirmed the hypothesis that, in the isolated nervous system, different extrinsic inputs can drive different gastric mill motor patterns. This enabled me to determine, for the first time in a network-driven motor circuit, that different motor patterns generated by the same motor circuit are paced by the same set of rhythm generator neurons. I further hypothesized and confirmed that these distinct motor patterns are retained at the level of at least some target muscles, and hence likely underlie different behavioral patterns. Lastly, I obtained data supporting the hypothesis that different extrinsic inputs distinctly modify the influence of a sensory feedback pathway on the relevant projection neurons (MCN1, CPN2), enabling the same sensory system to have different effects on different gastric mill rhythms. These results provide among the most detailed comparisons of how motor patterns generated by a single sensorimotor system are selected and regulated. The results thereby provide evidence for several novel cellular and synaptic mechanisms that expand our appreciation of the number of degrees of freedom available to even small sensorimotor systems.
... Moreover, our study showing that the site-specific muscle loss in the RA, which is the superficial trunk muscle, not only correlated with the sit-up test, but also with the 10-m walking time and is therefore relevant to locomotion. Our results agree with the previous studies that demonstrated a relationship between the CSA of the RA and the 6 min walk test in elderly persons (Saunders et al., 2004;Shahtahmassebi et al., 2017). Given that it has been observed that the abdominal muscles are gradually recruited during increasing locomotion speed (Saunders et al., 2004;2005), the muscle would therefore contribute to high-speed locomotion. ...
... Our results agree with the previous studies that demonstrated a relationship between the CSA of the RA and the 6 min walk test in elderly persons (Saunders et al., 2004;Shahtahmassebi et al., 2017). Given that it has been observed that the abdominal muscles are gradually recruited during increasing locomotion speed (Saunders et al., 2004;2005), the muscle would therefore contribute to high-speed locomotion. These results imply that the preservation of the trunk muscle size may also be an important factor to prevent LS. ...
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Although locomotive syndrome (LS) is a condition of reduced mobility, little information is available regarding the loss of site-specific skeletal muscle mass. The aim of the present study is to examine site-specific muscle loss in elderly males with LS. A total of 100 men ranging in age from 65 to 74 years were divided into two groups (LS and non-LS) using LS risk tests including the stand-up test, two-step test, and the 25-question geriatric locomotive function scale Muscle thickness (MTH) at eight sites—anterior and posterior thigh (AT and PT, respectively), anterior and posterior lower leg (AL and PL, respectively), rectus abdominis (RA), anterior and posterior upper arm (AU and PU, respectively), and anterior forearm (AF)—was evaluated using B-mode ultrasound. Furthermore, the 30-s chair stand test (CS-30), 10-m walking time, zig-zag walking time, and sit-up test were assessed as physical functions. There were no significant differences in age and body mass index between the LS and non-LS groups. The percentage of skeletal muscle was lower in the LS group than in the non-LS group. Although there were no differences in the MTH of AU, PU, AF, PT, Al and PL, site-specific muscle loss was observed at RA and AT in the LS group. CS-30, 10-m walking time, zig-zag walking time, and sit-up test in the LS group were all worse than those in the non-LS group. The MTHs of RA and AT were both correlated to those physical functions. In conclusion, the LS group had site-specific muscle loss and worse physical functions. This study suggests that site-specific changes may be associated with age-related physical functions. These results may suggest what the essential characteristics of LS are.
... At the same time, these muscles all contract rhythmically to actively assist ventilation during forced breathing (19). The close relationship between ventilation and spine erector muscle activation has been demonstrated previously by a number of studies; however, its function has been limited only to stabilizing the spine and not contributing to active inspiration (20)(21)(22). ...
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Background and Objective: To analyse the range of motion of the thoracic spine by radiographically measuring changes in the sagittal profile of different thoracic segments during maximal inspiration and exhalation. The starting hypothesis was that forced deep breathing requires an active, but non-uniform widening of the lordotic–kyphotic range of motion of the different thoracic segments. Methods: Cross-sectional study. Participants were 40 healthy volunteers aged 21–60. Conventional anteroposterior and functional sagittal chest radiographs were performed during maximal inspiration and exhalation. The range of motion of each spinal thoracic functional segment, global T1–T12 motion, and the sagittal displacement of the thoracic column during breathing were measured. Considering the different type of ribs and their attachment the spine and sternum, thoracic segments were grouped in T1–T7, T7–T10, and T10–T12. The displacement of the thoracic spine with respect to the sternum and manubrium was also recorded. Results: The mean difference from inspiration to exhalation in the T1–T12 physiologic kyphosis was 15.9° ± 4.6°, reflecting the flexibility of the thoracic spine during deep breathing (30.2%). The range of motion was wider in the caudal hemicurve than in the cranial hemicurve, indicating more flexibility of the caudal component of the thoracic kyphosis. A wide range of motion from inspiration to exhalation was found at T7–T10, responsible for 73% of T1–T12 sagittal movement. When the sample was stratified according to age ranges (20–30, 30–45, and 45–60 yr.), none of the measurements for inspiration or exhalation showed statistically significant differences. Only changes at this level showed a positive correlation with changes in the global thoracic kyphosis (r = 0.794, p <0.001). Conclusion: The range of motion of the thoracic spine plays a relevant role in respiration dynamics. Maximal inspiration appears to be highly dependent on the angular movements of the T7–T10 segment.
... It follows that the decrease of IO/TrA activation during forward bending could reflect that their action against anterior shear was suboptimal at full trunk flexion, as already shown for ES (McGill et al., 2003) or that the forward bending task was not sufficiently loaded to require the increase of IO/TrA contraction that was already reported for resisted trunk lowering and lifting. Also, a spine lordosis-related increase of TrA (as compared to flexed posture) was already shown in static abdominal drawing-in and segmental movement (Pinto et al., 2011a(Pinto et al., , 2011b, during repeated arm flexion (Hodges et al., 2001) and gait (Saunders et al., 2004) where TrA and IO tonic activation may ensure the lumbopelvic lordosis required in the erected position. Future studies should use real-time recordings of spine position concurrently to EMG recordings to further address the link between IO/TrA muscles and lumbar lordosis in functional tasks. ...
Article
Introduction: Chronic low back pain (CLBP) and fear of movement (kinesiophobia) are associated with an overactivation of paravertebral muscles during forward bending. This impairs spine motor control and contributes to pain perpetuation. However, the abdominal muscles activation is engaged too in spine stabilization but its modulation with kinesiophobia remains unknown. Our study tested whether CLBP and kinesiophobia affected the activation pattern of abdominal muscles during trunk flexion/extension. Methods: Surface electromyographical recordings of the internal oblique/transversus abdominis (IO/TrA) and external oblique (EO) muscles were analyzed in 12 people with CLBP and 13 pain-free subjects during low-velocity forward bending back and forth from erected posture. Tampa Scale of Kinesiophobia was also administrated. Results: IO/TrA activation, but not EO, was modulated across the phases of movement in both groups, i.e. maximal at onset of flexion and end of extension, and minimal at full flexion. In CLBP group only, IO/TrA activation was increased near to full trunk flexion and in correlation with kinesiophobia. Conclusions: The phase-dependence of IO/TrA activation during trunk flexion/extension in standing may have a role in spine motor control. The influence of kinesiophobia in CLBP should be further investigated as an important target in CLBP management.
... Both EO and RA were mainly unresponsive to treadmill grade modifications, while ES and MU (the spine extensors) were significantly more active in uphill, rather than in level W and PW. In addition, and in line with previous findings [7,26,27], higher speeds resulted in elevated trunk muscle activity both during W and PW. However, while EO ACT and RA ACT increased markedly with the speed increment, only small changes were observed in ES ACT and MU ACT , especially at GRADE 0 . ...
Article
Given their functional role and importance, the activity of several trunk muscles was assessed (via surface electromyography - EMG) during Walking (W) and Pole Walking (PW) in 21 healthy adults. EMG data was collected from the external oblique (EO), the erector spinae longissimus (ES), the multifidus (MU), and the rectus abdominis (RA) while performing W and PW on a motorized treadmill at different speeds (60, 80, and 100% of the highest speed at which the participants still walked naturally; PTS-60, PTS-80 and PTS-100, respectively) and grades (0 and 7%; GRADE-0 and GRADE-7, respectively). Stride length, EMG area under the curve (AUC), muscles activity duration (ACT), and percentage of coactivation (CO-ACT) of ES, MU and RA, were calculated from the averaged stride for each of the tested combinations. Compared to W, PW significantly increased the stride length, EO-AUC, RA-AUC and the activation time of all the investigated muscles, to different extents depending on treadmill speeds and grades. In addition, MU-AUC was higher in PW than in W at GRADE-0 only (all speeds, p<0.01), while ES-AUC during W and PW was similar at all the speeds and grades. These changes resulted in longer CO-ACT in PW than W, at GRADE-0-PTS-100 (p<0.01) and GRADE-7 (all speeds, p<0.01). In conclusion, when compared to W, PW requires a greater engagement of the abdominal muscles and, in turn, a higher control of the trunk muscles. These two factors taken together may suggest an elevated spinal stability while walking with poles.
... Thus, studies have actively investigated trunk stabilization exercises. Trunk stability is related to the body's ability to move and involves increased activity of the core muscles and erector spinae 3,4) . ...
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[Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength.
... The response of the superficial muscles is linked to the direction of force, whereas the activity of the TrA and deep part of the LM is independent of the direction of force (Hodges 2003). During dynamic movement, controlled activation of the LM and TrA might provide a strategy to simplify the control of intervertebral translation and ensure sufficient stability of the lumbar spine without requiring a concurrent increase in activity of the larger torque producing trunk muscles and compromising the intended movement trajectory (Saunders, Rath & Hodges 2004, McCook, Vicenzino & Hodges 2009). ...
... Fittingly, trunk muscle activity has been shown to increase with increasing speed of locomotion in man (Anders et al., 2007, Anders et al., 2009, Capellini et al., 2006 and in equids (Robert et al., 2001, Robert et al., 2002. It has been demonstrated that in man, the relative timing in muscle activity does not change considerably with increasing speed, although muscle-dependent changes in phasic behavior can be observed (Anders et al., 2007, Saunders et al., 2004. The humans in this study were able to select a speed of locomotion which was comfortable to them, and an appropriate locomotion speed was selected for each individual sheep based on observation. ...
Article
Sheep are commonly used as an animal model for the human lumbar spine, but similarities in trunk muscle activity of humans and sheep during functional tasks, such as locomotion have not been investigated. Therefore, the aim of the study was to evaluate trunk and pelvic limb muscle activity during walk and run/trot gaits in man and sheep. Electromyography of the muscles erector spinae (ES), gluteus maximus (GM), rectus abdominis (RA), obliquus externus (OE) and obliquus internus (OI) were collected in 24 humans and 15 sheep during treadmill walk and run/trot. Kinematic data from the tarsus (human) or metatarsus (sheep) were obtained to define motion cycles and determine stride characteristics. Mean and range of normalised muscle activity were calculated. In phasic muscles, the occurrence of the maximum was reported. At walk, mean activity was greater in humans for all three abdominal muscles (all P<0.01). At the run/trot, mean activity of ES was significantly greater in sheep (P<0.05) and mean activity of ...
... Abdominal muscle EMG was recorded during self-paced walking. This task was repeated four times (Saunders et al., 2004). ...
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The purpose of this study was to investigate the difference in the onset times of the abdominal muscle following a rapid arm task in lumbar spinal stenosis (LSS). In total, 32 patients with LSS were recruited from W oriental hospital. Muscle activity onset of the internal oblique (IO) and external oblique (EO) muscles was measured by electromyography (EMG) activity with a rapid arm movement and during the performance of a walking task. The LSS group demonstrated a significantly later onset of the IO, EO, and rectus abdominal (RA) muscles than the normal group. The deltoid reaction time of the normal group demonstrated significantly earlier activations of IO and EO, while the deltoid reaction time of the LSS group demonstrated significantly delayed activations of IO and RA. The EMG measurements of the IO, EO, and RA muscles while standing and walking were reliable and they offer empirical information about the trunk muscle activation of LSS patients.
... These results are consistent with the findings from previous studies, which indicated a relationship between trunk stabilization and extremity functions. [33][34][35][36] Miyake et al. demonstrated upper limb function improvement following the performance of stabilization exercises in a healthy population. In the same study, the positive effects of core stabilization exercises on limb ataxia were demonstrated with a two-dimensional movement analysis system in a patient with cerebellar ataxia. ...
Article
Purpose: To investigate the effects of different exercise protocols on ataxia in patients with multiple sclerosis (MS). Method: A total of 42 MS patients, 17 male and 25 female (Expanded Disability Status Scale (EDSS): 3–5), were enrolled in this randomized controlled study. The patients were divided into three groups: a balance training (BT) group, a lumbar stabilization (LS) group and a task-oriented training (TT) group. All groups received balance training; additionally, the LS group received lumbar stabilization exercises, and the TT group received task-oriented training. The Berg Balance Scale (BBS), International Cooperative Ataxia Rating Scale (ICARS), Functional Reach Test (FRT), 2-Minute Walk Test (2MWT), Sensory Organization Test (SOT), and measurement of Somatosensory Evoked Potentials (SSEPs) were performed before and at the end of the 18 training sessions. Results: The BBS, ICARS, FRT, 2MWT, and composite balance score of the SOT were improved in all groups. The ICARS kinetic function sub-score and the left limb cortical onset amplitudes of SSEPs were increased significantly in both the TT and the LS groups. The ICARS total score, composite balance score, and 2MWT were different between groups (p < 0.05). According to multiple comparison analyses of the ICARS total score and the composite balance score, the LS, and the TT group were different from the BT group (p < 0.005), while the LS and the TT groups improved similarly (p > 0.005). The 2MWT results were better for the LS group than the BT group, while the BT and the TT groups improved similarly. Conclusion: Balance training alone is not sufficient for rehabilitation of ataxic MS patients. A combination of lumbar stabilization exercises or task-oriented training increases the success of balance rehabilitation. • Implications for rehabilitation • Multiple sclerosis is a chronic inflammatory and autoimmune disease of central nervous system and ataxia is one of the most challenging symptoms of this disease. • Different exercise modalities are commonly employed to control ataxic symptoms in MS patients. • Lumbar stabilization exercises or task-oriented training should be considered as complementary approach to improve balance and coordination in ataxic multiple sclerosis patients.
... The trunk muscles play important roles in successful sports performance and satisfactory physical locomotion, especially athletes and older people 1) . For example, an increase in trunk muscle size contributes to enhanced performance in sports players 2) , whereas, in contrast, a reduction in the trunk muscle size relates to increased fall risk in elderly people 3) . ...
Article
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[Purpose] Ultrasonography (US) is widely applied to measure the muscle size in the limbs, as it has relatively high portability and is associated with low costs compared with large clinical devices such as magnetic resonance imaging (MRI). However, the applicability of US for evaluating trunk muscle size is poorly understood. This study aimed to examine whether US-measured muscle thickness (MT) in the trunk abdominal and back muscles correlated with MT and muscle cross-sectional area (MCSA) measured by MRI. [Subjects and Methods] Twenty-four healthy young males participated in this study. The MT and MCSA in the subjects were measured by US and MRI in a total of 10 sites, including the bilateral sides of the rectus abdominis (upper, central, and lower parts), abdominal wall, and multifidus lumborum. [Results] The interclass correlation coefficients of US-measured MT on the total 10 sites showed excellent values (n=12, 0.919 to 0.970). The US-measured MT significantly correlated with the MRI-measured MT (r=0.753 to 0.963) and MCSA (r=0.634 to 0.821). [Conclusion] US-measured MT could represent a surrogate for muscle size measured by MRI. The application of US for evaluating trunk muscle size may be a useful tool in the clinical setting.
... In general, stroke patients experience weakness of muscles on the affected side [3]. The trunk muscle is the biggest part of our body and plays an important role in the stabilization and movement of body segments. ...
Article
The purpose of this study was to examine the effects of the core-stability training on postural control ability and respiratory function in patients with chronic stroke. 30 subjects were randomly assigned to 2 groups. Experimental group (n=15) received core-stability training and control group (n=15) received general exercise. Each program was performed 30 min, 4 times a week for a period of 8 weeks.Core-stability training included a therapeutic program to train abdominal muscle strength. General exercise include weight bearing and weight shifts and joint movements to improve flexibility and the range of motion. For all 30 subject, the items measured before the training were measured after the therapeutic intervention. To observe postural control changes, we measured maintenance & change of posture, balance and coordination ability with postural assessment scale for stroke (PASS) and trunk impairment scale (TIS). The respiratory functions were measured forced vital capacity (FVC), forced expiratory volume at one second (FEV1) using spirometer. After training, the PASS and TIS scores was significantly improved in experimental group (p<.05), and the experimental group showed significantly difference from control group (p<.05). In respiratory function test, experimental group more significantly increased than before (p<.05), and showed significantly difference from control group (p<.05). The results of this study showed that the core-stability training may be appropriate for improving the trunk stability and respiratory function in chronic stroke patients.
... This disease becomes the cause of considerable morbidity and mortality worldwide [1]. In general, stroke patients experience weakening of muscles on the affected side [2]. In particular, the weakening of trunk muscles moves the center of gravity backward, thereby causing thoracic bending. ...
... As activation of trunk muscles is necessary for both postural and respiratory functions (Hodges and Gandevia, 2000a;Saunders et al., 2004), the activation patterns of many trunk muscles during a postural task will depend also on the respiration cycle. It is plausible that some activation reported to be antagonistic to a trunk load may serve a respiratory function rather than contribution to control of spine posture. ...
Article
Controversy exists in the literature regarding antagonist activity of trunk muscles during different types of trunk loading, and the direction-specificity of activation of trunk muscles, particularly the deeper trunk muscles. This study aimed to systematically compare activation of a range of trunk muscles between directions of statically applied loads, and to consider the impact of breathing in this activation. In a semi-seated position, 13 healthy male participants resisted moderate inertial loads applied to the trunk in eight different directions. Intramuscular electromyography was recorded from eight abdominal and back muscles on the right side during 1 s prior to peak inspiration/expiration. All muscles demonstrated a directional preference of activation. No muscle displayed antagonistic activation during loading conditions of an intensity that exceded that recorded in upright sitting without a load. During these moderate intensity sustained efforts, trunk muscle activation varied little between respiratory phases. Antagonistic muscle activation of amplitude equivalent to the activation recorded in upright sitting without load is sufficient to maintain control of the spine during predictable and sustained low load tasks.
... While an early report suggested a differential fibre type distribution within multifidus [31], it is contemporarily held that the regional distribution of fibre types is consistent among the posterior paravertebral muscles [32]. Intramuscular EMG (iEMG) studies examining sagittal plane motion showed differential activation within multifidus [23,26,33], with similar potential for the thoracolumbar erector spinae [34][35][36]. However, voluntary differential activation is challenging for many people [37,38] and it is unclear whether differential activation of the spinal muscles can be integrated into rehabilitation. ...
Article
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The influence of age on spinal muscle activation patterns and its relation to kinematics is poorly understood. We aimed at understanding age-related changes to spine and trunk muscle activity in addition to spinal and lower limb kinematics during treadmill walking under various conditions. An observational study was conducted evaluating asymptomatic young (n = 10; 3F, 7M; 26.3±2.5yrs) and older (n = 9; 3F, 6M; 67.1±4.2yrs) adults’ treadmill walking at 2km/h and 4km/h, each at 0, 1, 5, and 10% inclination. Unilateral (right side) electromyography (EMG) was recorded from deep and superficial multifidus (intramuscular) and erector spinae and abdominal obliques (surface); trunk and leg kinematics were also measured. Muscle activity was characterised by peak amplitude and duration of activity, and the time-point of peak amplitude in the gait cycle (0–100%). Peak activation in older adults was lower for the superficial multifidus (p<0.0001) and higher for the thoracolumbar (p<0.001) and lumbar erector spinae (p<0.01). The duration of activation was longer in older adults for all muscles (p<0.05) except the superficial multifidus, and longer during faster walking for all participants. The time-point of peak amplitude in the gait cycle was earlier in older participants for the external obliques (p<0.05). Walking speed appeared to influence muscle activity more than inclination. Older adults used less spine, trunk and lower limb motion, except at the ankle. Age-related differences within multifidus and between paravertebral and trunk muscles were inconsistent. Walking at 4km/h at 5–10% inclination may specifically target the lumbar paravertebral muscles.
... This increasing noise resulting from an increase in PA intensity may be explained by (i) artefact movements, (ii) changing postures, and (iii) movements of the soft tissues of the subjects. During intense PA, more movements occur that are not related to respiration (Saunders et al. 2004), and because of these additional movements, the magnetometer signal is more noisy than it is under resting conditions. Notably, although the ''Biking: 110 W'' activity is more intense than the ''Biking: 90 W'' activity, the errors and R 2 values are higher and lower, respectively, for the latter PA. ...
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Purpose: The purposes of this study were to both improve the accuracy of respiratory volume (V) estimates using the respiratory magnetometer plethysmography (RMP) technique and facilitate the use of this technique. Method: We compared two models of machine learning (ML) for estimating [Formula: see text]: a linear model (multiple linear regression-MLR) and a nonlinear model (artificial neural network-ANN), and we used cross-validation to validate these models. Fourteen healthy adults, aged [Formula: see text] years participated in the present study. The protocol was conducted in a laboratory test room. The anteroposterior displacements of the rib cage and abdomen, and the axial displacements of the chest wall and spine were measured using two pairs of magnetometers. [Formula: see text] was estimated from these four signals, and the respiratory volume was simultaneously measured using a spirometer ([Formula: see text]) under lying, sitting and standing conditions as well as various exercise conditions (working on computer, treadmill walking at 4 and 6 km[Formula: see text], treadmill running at 9 and 12 km [Formula: see text] and ergometer cycling at 90 and 110 W). Results: The results from the ANN model fitted the spirometer volume significantly better than those obtained through MLR. Considering all activities, the difference between [Formula: see text] and [Formula: see text] (bias) was higher for the MLR model ([Formula: see text] L) than for the ANN model ([Formula: see text] L). Conclusion: Our results demonstrate that this new processing approach for RMP seems to be a valid tool for estimating V with sufficient accuracy during lying, sitting and standing and under various exercise conditions.
... These parallel actions via distinct mechanisms suggest a need to maintain this coordination pattern under different circumstances. Behavioral coordination via intercircuit regulation occurs in many systems, such as the linkage between respiration and locomotion, and whisking and locomotion (Bartos et al. 1999;Bernasconi and Kohl 1993;Cao et al. 2012;Gravel et al. 2007;Saunders et al. 2004;Wood et al. 2004), although in most cases the underlying mechanisms remain to be determined. ...
Article
Microcircuit modulation by peptides is well established, but the cellular/synaptic mechanisms whereby identified neurons with identified peptide transmitters modulate microcircuits remain unknown for most systems. Here, we describe the distribution of GYRKPPFNGSIFamide (Gly1-SIFamide) immunoreactivity (Gly1-SIFamide-IR) in the stomatogastric nervous system (STNS) of the crab Cancer borealis and the Gly1-SIFamide actions on the two feeding-related circuits in the stomatogastric ganglion (STG). Gly1-SIFamide-IR localized to somata in the paired commissural ganglia (CoGs), two axons in the nerves connecting each CoG with the STG, and the CoG and STG neuropil. We identified one Gly1-SIFamide-IR projection neuron innervating the STG as the previously identified modulatory commissural neuron 5 (MCN5). Brief (~10 s) MCN5 stimulation excites some pyloric circuit neurons. We now find that bath applying Gly1-SIFamide to the isolated STG also enhanced pyloric rhythm activity and activated an imperfectly coordinated gastric mill rhythm that included unusually prolonged bursts in two circuit neurons [inferior cardiac (IC), lateral posterior gastric (LPG)]. Furthermore, longer duration (>30 s) MCN5 stimulation activated a Gly1-SIFamide-like gastric mill rhythm, including prolonged IC and LPG bursting. The prolonged LPG bursting decreased the coincidence of its activity with neurons to which it is electrically coupled. We also identified local circuit feedback onto the MCN5 axon terminals, which may contribute to some distinctions between the responses to MCN5 stimulation and Gly1-SIFamide application. Thus, MCN5 adds to the few identified projection neurons that modulate a well-defined circuit at least partly via an identified neuropeptide transmitter and provides an opportunity to study peptide regulation of electrical coupled neurons in a functional context. NEW & NOTEWORTHY Limited insight exists regarding how identified peptidergic neurons modulate microcircuits. We show that the modulatory projection neuron modulatory commissural neuron 5 (MCN5) is peptidergic, containing Gly1-SIFamide. MCN5 and Gly1-SIFamide elicit similar output from two well-defined motor circuits. Their distinct actions may result partly from circuit feedback onto the MCN5 axon terminals. Their similar actions include eliciting divergent activity patterns in normally coactive, electrically coupled neurons, providing an opportunity to examine peptide modulation of electrically coupled neurons in a functional context.
... Therefore, the contraction of the diaphragm increases the pressure in the abdominal cavity leading to increases in the spine stability (Hodges and Gandevia, 2000). In the previous studies, postural control and respiratory capacity were correlated with each other ( Saunders et al., 2004;Zafar et al., 2018). Shin et al. (2015) re- ported that sitting posture affects respiratory function. ...
Article
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The purpose of this study was to examine the effects of Vojta approach on the gross motor function and diaphragm movement in children with spastic cerebral palsy (CP). Ten children with spastic CP were randomly assigned to a general physiotherapy group (trunk strengthening exer-cise and gait training) (n=5) and a Vojta approach group (n=5). Inter-ventions were implemented for 30 min per time, 3 times a week for a to-tal of 6 weeks. Ultrasonography was used to measure the areas of the diaphragm (during inspiration, expiration) before and after the interven-tions, the gross motor function measure (GMFM)-88 was used for eval-uation of the gross motor function. In the results of this study, there was a significant difference between before and after GMFM-sitting in the experimental group (P < 0.05), a significant difference in changes of in-spiration between the two groups (P < 0.05). Given these results, Vojta approach may be presented as an effective treatment method for im-proving sitting position and diaphragm movement during inspiration in children with spastic CP.
... 32 Saunders et al. in 2004 explained that when trunk stability is required then the combination of phasic and tonic exercises between the Transversus Abdominus and diaphragm should be used. 33 So, in our study, we concluded that because of increased contractions of the diaphragm, the mean score on Trunk Impairment scale in the group DBM increased significantly when compared to the scores in group ADIM. ...
Background: one of the most frequent determinants of long-term disability in the adults is Stroke which may affect the normal functioning of trunk and hence may disturb balance. Objective: to assess the effects of “Abdominal Drawing-in Maneuver” and “Diaphragmatic Breathing Maneuver” in improving the stability of trunk in stroke patients. Methods: A quasi-experimental study including 36 patients with confirmed diagnosis of the first incident of stroke was conducted. Patients were assigned randomly in two groups ADIM and DBM. Outcome measurements were evaluated using the “Trunk Impairment Scale”. Results: after 4 weeks of training; “Trunk Impairment Scale” score improved significantly. Between groups comparison shows that trunk stability significantly improved in the group DBM as compared those in the group ADIM. Conclusion: it may be concluded that Diaphragmatic Breathing Maneuver can be an effective technique in improving trunk stability in stroke patients.
... There is a relationship between respiratory muscle activation and the timing of contraction of the trunk muscles during extremity movements; the control of the trunk and the extremities may involve interaction with the diaphragm, which is the key respiratory muscle. 34,35 Impaired respiratory muscle activation may lead to a decrease in core stability required for normal balance and ambulation. 17 Reduced control of mediolateral stability and an increased risk of fall have been reported in individuals with chronic obstructive pulmonary disease. ...
Article
The aim of the study was to investigate the effects of inspiratory muscle and balance training on pulmonary function, respiratory muscle strength (RMS), functional capacity, and balance in children with hemiplegic cerebral palsy (CP). Thirty children with hemiplegic CP (Gross Motor Function Classification System I–II) included in this study. The control group (n = 15) underwent conventional physiotherapy rehabilitation program (CPRP) that included balance exercises, and the training group’s (n = 15) program included inspiratory muscle training (IMT) in addition to CPRP for 8 weeks. The outcome measures were pulmonary function test, RMS measurement, the six-minute walk test (6MWT), and balance tests. There were no significant differences in the score changes of pulmonary function, balance, and 6MWT distance between groups (p > .05), whereas maximum inspiratory and expiratory pressure further increased in the training group (p > .05). RMS assessment and the identification of children who need it, and adding IMT to CPRP will contribute greatly to the rehabilitative approach of children with CP.
... Regardless of the approach, all balance models share the concepts of CoM (Centre of Mass), Centre of Pressure (CoP) and the BoS (Base of Support). While the CoM concept is straightforward and precisely defined, this cannot be said for both BoS and CoP that present multiple definitions within the same model [4,7,9,35,37,49,53,65,66,[66][67][68][69][70][71][72][73][74]. The CoP is defined as the point of application of the ground reaction. ...
Thesis
With the rapidly ageing of the world' s population, the WHO predicted that, by 2050, there will be about one billion people who are 65 years or older suffering from mobility-related problems. Robotic rehabilitation has been proven to provide effective therapies for people with motor deficiencies. Although multiple solutions have been developed for both balance and gait rehabilitation, both exoskeletons and robotic walkers have been shown to not have any benefit when compared with current therapies. A possible justification is a significant alteration of the activity dynamics (i.e. balance and locomotion) that prevents the skill translatability in daily living. The current knowledge about bipedal dynamics was reviewed to identify a viable solution for the improvement of both locomotion and balance therapy. The review revealed a gap in the current knowledge in the human balance and locomotion motor control, which does not provide a satisfactory explanation of how humans control and optimize their locomotion. The following hypotheses have been developed to address the limitations of bipedal models: first, the brain accounts for fixed fulcrum for the legs' inverted pendulum model, and second, the legs are not simply synchronised but are deployed as coupled oscillators. These hypotheses have enabled the formulation of an algebraic model for human locomotion that has been tested against data from multiple experiments. The results show that the proposed model can produce outputs that are fully contained within the variance of human data in both the centre of mass transverse plane trajectories and the antero-posterior swing trajectories of the feet. On the contrary, the estimation of the centre of mass of the vertical trajectories has not given definitive results, but it provided proof that most of the energy misestimation can be associated with the ankle strategies. The deeper understanding of human locomotion strategies has led to identify in the high stiffness interfaces used in most of current devices a probable cause of the altered locomotion strategies. A 5 degrees of freedom selective compliance mechanism has been designed to improve the interface between the mobile robotic base and the patient. The proposed design introduces a buffer area to minimise the interaction forces and to increase manoeuvrability. Two prototypes of 5 degrees of freedom interface have been developed. Although they share the same mechanism design, they have different joint range of motion and inertias. The first prototype has a larger motion range and weighs about 12 kg, while the second prototype has a lower inertia and a smaller range of motion. The two prototypes have been mounted on two manual carriages to study the alteration of the gait strategies generated in healthy subjects. The first prototype has been tested with 5 female subjects. The data show an alteration of their speed, step length, step width and step frequency by -23%, -22%, -7% and -2.8%, respectively. The second prototype, on the other hand, has been tested with 12 healthy subjects (7 males and 5 females) on a highly manoeuvrable carriage that allows the regulation of the interface height. The data report a reduction in the walking speed and step length of 7.6% and 9.7%, respectively; they instead increase the step width and the step frequency of 9.2% and 2.55%, respectively. Moreover, the data also suggest that the alterations generated by the proposed interface may be due to the selection of a more conscious movement strategies made from the subjects rather than their response to an external perturbation. In conclusion, the knowledge gathered about both bipedal equilibrium and human motor-control of locomotion served as a guide to build a better interface for the pelvis that is able to provide harness support and which was the main scope of this work. Furthermore, this knowledge has beneficial outcomes not only in the development of rehabilitative technologies but also in improving bipedal robots' controllers. Link: http://hdl.handle.net/10356/73249
... The hip flexor muscles showed not only an anticipation of their recruitment but also a significant postponement of their deactivation across speeds, underlying the crucial importance of core muscles in exerting increasing propulsive power at elevated speeds. These results are in line with previous data concerning running (Saunders et al. 2004), that showed how deep and superficial trunk muscles (paraspinals but also rectus abdominis muscle) increase the percentage duration of their activation across running speeds. Moreover, our data suggested that when increasing during double speed, the hip flexors take on the typical behavior of postural muscles, gradually anticipating the action of upper-limb extensor muscles. ...
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Purpose: To evaluate the level of activation and timing of upper- and lower-body muscles during double poling at different speeds on snow. Methods: Nineteen well-trained cross-country skiers volunteered to double pole on a flat snowy track at different speeds (15, 18, 21 km h(-1)). The target speeds could be maintained by the skiers thanks to the use of an audio-pace system in combination with cones spaced equally alongside the track. Only 11 subjects were finally included in the analysis, since their actual speeds, calculated through a photocell system, were within ±0.5 km h(-1) from those requested. Cycle and poling durations were measured from the recordings of an accelerometer attached to a wrist, while the pattern and the level of muscle activation were evaluated from electromyographyc signals. Results: Double poling speed did not alter the sequence of muscle activation that started with hip flexors, continued with trunk flexors, shoulder, elbow and trunk extensors and ended with ankle plantar-flexors. However, higher speeds required an increasing involvement of thigh, trunk and shoulder muscles (P < 0.05) as well as an anticipation of their activation before pole plant (P < 0.05). Conclusions: A progressively earlier activation of trunk and lower limb muscles is a coordinative strategy that allows rapid achievement of optimal body posture prior to the exertion of poling phase. Moreover, earlier activation of these muscles as the speed increases provides adequate muscle stiffness in the shoulder and core regions for the acceptance of the poling load.
... Module 4 pre engaged the trunk muscles and it was activated in the stance phase. Researchers reported that trunk muscles are activated to enhance the rigidity of the trunk, stabilize the lumbar spine and pelvic girdle, and transmit ground reaction forces efficiently during push-off, which ends the stance phase [26][27][28] . From the activation coefficient of module 4 pre , the timing of the trunk muscle activity was similar to that reported by Saunders et al. 26) ; therefore, module 4 pre may be activated to stabilize posture through the trunk muscles during the stance phase. ...
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[Purpose] The purpose of this study was to investigate the modular control of locomotor tasks and compared the modules before and after a running intervention. [Subjects and Methods] Electromyographic measurements were performed on eight young, healthy males engaged in a 60s run on a treadmill at 2.8 m/s before and immediately after the 600s of running intervention. Electromyographic data for 15 trunk and lower-limb muscles on the right side were recorded. Muscle synergies were extracted from the electromyography signals using non-negative matrix factorization. [Results] Four modules explained the electromyographic activity of all muscles and had the functions of load acceptance (module 1), push-off (module 2), preparation of landing (module 3), and trunk-stabilization activity during the stance phase (module 4). Modules 1, 2, and 3 matched the basic modules reported in previous studies; whereas, module 4 was different before and after the intervention. [Conclusion] Before the intervention, module 4 engaged the trunk muscles and it was activated in the stance phase during running. However, after the intervention, module 4 engaged the muscles around the pelvis and it was activated after landing. This result suggests that the posture control changes from the trunk muscles to the lower-limb muscles after 10 minutes running.
... Ces résultats étaient attendus en raison de la gamme plus importante deV E lors d'exercices d'intensités plus élevées. De plus, au cours d'une AP intense, des mouvements plus importants sans être nécessairement liés à la respiration se produisent (Saunders et al. 2004;Dumond et al. 2017). Ces mouvements contribuent à l'augmentation des erreurs d'estimation. ...
Thesis
L'activité physique (AP) est primordiale pour la santé. La quantification de l'AP occupe une place majeure dans les recherches scientifiques qui étudient la relation entre l'AP et ses effets sur la santé. L'AP est quantifiée en termes de dépense énergétique (DE). Les techniques de référence pour mesurer DE sont encombrantes et invasives. Des nouveaux appareils portables non invasifs sont développés pour pallier les problèmes liés à l'utilisation des méthodes de référence. Parmi ces appareils, la pléthysmographie respiratoire par magnétométrie (PRM) a été récemment développées. PRM est basée sur la mesure des distances longitudinales et transversales thoraciques et abdominales.L'objectif de cette thèse est d'évaluer la capacité de PRM à estimer VE et DE au cours d'AP d'intensités faibles à élevées en utilisant des algorithmes d'apprentissage automatique.Les principaux résultats de nos travaux montrent :1) Que PRM permet d'estimer VE et DE pendant des AP faibles à élevées.2) Qu'un modèle non linéaire est plus pertinent qu'un modèle linéaire pour estimer VE.3) Que l'individualisation des modèles offre une meilleure performance pour l'estimation de VE et de DE.4) Que PRM estime avec précision DE pour n'importe quelle intensité même pour celles les plus élevées.5) Qu'une approche activité spécifique est plus pertinente pour estimer DE, et qu'une étape de reconnaissance de l'AP est nécessaire avant d'estimer DE.De nouvelles études doivent cependant être réalisées pour tester PRM sur une large population et dans des conditions de vie libre.
... Differential Fig. 4 Yearly change (and 95% CIs) of lumbar paravertebral muscles fat content for Asians [11] and Caucasians [8] according to lumbar level. Change for each ethnicity (per study) were determined separately and are presented together, with results from Lee et al. [11] inverted to reflect increasing proportion of fatty content patterns of FI distribution may have biomechanical consequences whereby subtle, and more obvious, differences in motor function [33][34][35][36][37] may be partially explained by the overall muscle composition. ...
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Purpose: Fatty infiltration (FI) is a feature of degenerating muscle that predominates in the low lumbar spine, associates with pain, and is confounded by age, spinal degeneration, and curvature. We determined rates for decline of lumbar muscle quality according to ethnicity, muscle, and spinal level in asymptomatic subjects. Methods: Cross-sectional simulation study assessing aggregated data; 650 Asians aged 20-89 years versus 80 Caucasians aged 20-62 years. Change in lumbar multifidus, erector spinae (ES), and psoas fat content were computed using synthetic data and Monte Carlo simulations. General linear regression models and multivariate adaptive regression splines enabled estimation of yearly decline rates [with 95% confidence intervals (CI)]. Results: ES at L1-5 (total) shows steeply reduced density (rate; CI) for Asians in older (>53.3 years) adulthood (-0.32; -0.27 to -0.36/year). For Asians, multifidus (-0.18; -0.15 to -0.20/year) and psoas (-0.04; -0.03 to -0.06/year) also decline, while ES in younger ≤53.3 years) adults does not (0.06; 0.01-0.12/year). Caucasian multifidus declines (increasing FI % rate; CI) insignificantly faster (L1-5; 0.23; 0.10-0.36%/year) than ES (0.13; 0.04-0.22%/year). Multifidus decline does not differ between ethnicities. ES in older Asians generally declines fastest across ethnicities and muscles, and particularly in the low lumbar levels. Low lumbar levels show higher rates of decline in Asians, with mixed level-dependencies apparent in Caucasians. Conclusions: Decline in lumbar muscle composition may differ between ethnicities and muscles. ES and low lumbar levels appear increasingly susceptible in Asians. Longitudinal studies examining rate of change to muscle composition may provide distinction between spinal conditions.
Article
Purpose Patients with multiple sclerosis (MS) with respiratory muscle weakness could have physical function impairments, given the functional/biomechanical link of the trunk stabilising system. Thus, clinicians could employ new treatment strategies targeting respiratory muscles to improve their physical function. This study pretends to evaluate the relationship between respiratory muscle strength, pulmonary function and pelvic floor function, and also to correlate these variables with physical function (gait function, disability and quality of life) in patients with MS. Methods 41 patients participated in this descriptive cross-sectional study. Respiratory muscle strength [maximal respiratory pressures (MIP/MEP)], pulmonary function (forced spirometry), pelvic floor function [urinary incontinence (UI)], physical function [Timed Up & Go (TUG) test, Barthel index and health status questionnaire (SF-12)] were evaluated. Results Respiratory muscle strength and pulmonary function were moderately related to UI (MIP: rho = −0.312; MEP: rho = −0.559). MEP was moderately related to physical function (TUG: rho = −0.508; Barthel index: rho = 0.418). Patients with and without expiratory muscle weakness showed differences in UI, pulmonary and physical function. Conclusion Patients with MS with greater deterioration in pulmonary function and respiratory muscle strength, especially expiratory muscles, showed greater deterioration in UI and physical function. Expiratory muscle weakness had a negative impact on urinary, physical and pulmonary function. • Implications for rehabilitation • Pulmonary function is associated with urinary incontinence and gait functionality in patients with multiple sclerosis (MS). • Expiratory muscle weakness is associated with impaired urinary and physical function in patients with MS. • The inclusion of respiratory muscle training to the rehabilitation programs of patients with MS could improve their pelvic floor disorders and physical function.
Article
Purpose The purpose of this study was to evaluate the accuracy of minute ventilation (V˙E) estimation using a novel method based on a non-linear algorithm coupled with cycle-based features. The experiment protocol was well adapted for remote health monitoring applications by exploiting data streams from respiratory magnetometer plethysmography (RMP) during different physical activity (PA) types. Methods Thirteen subjects with an age distribution of 24.1±3.4 years performed thirteen PA ranging from sedentary to moderate intensity (walking at 4 and 6 km/h, running at 9 and 12 km/h, biking at 90 W and 110 W). In total, 3359 temporal segments of 10s were acquired using the Nomics RMP device while the iWorx spirometer was used for reference V˙E measurements. An artificial neural network (ANN) model based on respiration features was used to estimate V˙E and compared to the multiple linear regression (MLR) model. We also compared the subject-specific approach with the subject-independent approach. Results The ANN model using subject-specific approach achieved better accuracy for the V˙E estimation. The bias was between 0.20±0.87 and 0.78±3 l/min with the ANN model as compared to 0.73±3.19 and 4.17±2.61 l/min with the MLR model. Conclusion Our results demonstrated the pertinence of processing data streams from wearable RMP device to estimate the V˙E with sufficient accuracy for various PA types. Due to its low-complexity and real-time algorithm design, the current approach can be easily integrated into most remote health monitoring applications coupled with wearable sensors.
Article
Objective: Patients with stroke may experience pulmonary dysfunction that reduces movement of the muscles involved in postural control and respiration. This study aimed to evaluate the relationship between postural control and respiratory muscle strength using pulmonary function testing. We sought to identify the respiratory function parameters that predict the functional outcomes patients with stroke at discharge. Design: We prospectively recruited 52 patients with first-ever stroke within 6 months of onset. Peak cough flow (PCF), maximal inspired pressure, maximal expired pressure, forced vital capacity (FVC), and forced expiratory volume in 1 second (FEV1) were measured at baseline and after 4 weeks of rehabilitation. The primary outcomes were trunk balance measured using the Trunk Impairment Scale (TIS) and functional outcomes measured using the Berg Balance Scale (BBS) and functional independence measure (FIM). Results: The initial PCF, FVC, and FEV1 values correlated with the TIS scores at admission; only the initial PCF and FVC were predictive factors for the final TIS score. Multivariable linear regression analysis showed that the initial PCF was a significant predictive factor for follow-up test scores at discharge: BBS (P<0.001) and FIM (P<0.025). Conclusion: Initial respiratory function was significantly correlated with trunk balance and the functional outcomes.
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CERTAIN PLYOMETRIC AND ISOMETRIC PROTOCOLS FAILED TO PRODUCE A POSTACTIVATION POTENTIATION IN VERTICAL JUMP AND BENCH PRESS THROW POWER OUTPUT. THE ISOMETRIC PROTOCOL IN PARTICULAR, NEGATIVELY AFFECTED THE STRONGEST MALE FENCERS. NONETHELESS, THE RESULTS CAN BE USEFUL IN GUIDING THE PRACTITIONER TOWARD EXPERIMENTATION WITH POSTACTIVATION POTENTIATION PROTOCOLS FOR OTHER ATHLETES.
Article
The purpose of our study was to measure gait parameters while performing ADIM giving feedback by using RTUI during walking on a treadmill. Thirty subjects were allocated into the ADIM group (n=15) and the placebo ADIM group (n=15). The gait was measured in pre and post training. Results: The gait was measured in pre and post training. In the results of gait parameters, there were significant differences between two groups at post- test (p<.05). The ADIM group, cadence, gait cycle, step length, stride length, double limb support showed significant differences (p<.05). All variables showed significant difference within the placebo ADIM group(p<.05). Conclusion: These results indicate that ADIM is helpful for developing gait stability and that clinician should recommend ADIM training to patients with walking problem. Further study needs to investigate the continuous effects of ADIM through the long-term study and include many subjects with various age and follow-up test.
Article
Background: There is a lack of evidence to assess whether gait functionality can be affected by the condition of the pelvic floor musculature in patients with multiple sclerosis (MS). Objective: To evaluate the relationship between pelvic floor functionality and general functional performance, and also their relationship depending on dependence degree in MS patients. Participants: Forty-three MS patients performed the study. The pelvic floor musculature and its functionality were evaluated by urinary incontinence (UI), fecal incontinence, and constipation. General functional performance was evaluated by the Barthel index, the Health Status Questionnaire Short Form-12 (SF-12), and the Timed Up and Go (TUG) test. Results: UI was moderately related to general functional performance (SF-12 Physical: R = -0.413; Barthel index: R = -0.501; TUG: R = 0.482). The comparative analysis showed differences between UI and gait functionality (P = .008), with poorer results in the TUG in patients with moderate/severe dependence (P < .001). Conclusion: UI appears to have a negative impact on the performance of daily living activities, walking, and the physical dimension of quality of life in patients with MS. In addition, patients with moderate or severe dependence showed higher UI and gait disturbance compared with those with mild dependence or independence.
Article
The activity of muscles in the trunk and lower limbs during sidestepping was recorded in nine healthy young men (control group) and three young men with groin pain syndrome. Muscle synergies among subjects were compared. Non-negative matrix factorization was used to extract muscle synergies from electromyographic data. Thereafter, to compare muscle synergies, a scalar product evaluating synergy coincidence was calculated. Three muscle synergies were extracted in both groups from non-negative matrix factorization analysis. In both groups, two out of three synergies were found to be the same by scalar product analysis. In one of these synergies, the oblique muscle, rectus femoris, and adductor muscle were activated before landing in mid-stance during the sidestep motion in the control group. Therefore, this synergy is thought to suppress excessive hip abduction. However, the peak timing of this synergy in the groin pain group was at mid-stance. This delay may cause hip instability because muscles must be activated before landing to enhance joint stability. Risk factors for groin pain are dysfunctional coordination between trunk and lower-limb muscles and decreased hip stability. Even though the number of subjects in this study was small, it is possible that delayed activation of this synergy may be related to the mechanism of injury in groin pain.
Article
An understanding of the function of trunk muscles is important for the treatment of low back pain as well as for the improvement of athletic performance. In particular, the importance of deep trunk muscles (local muscles) has been documented in the recent literature. In this chapter we report on investigation about activity patterns of deep trunk muscles during lumbar stabilization exercises and sports activities. We recorded muscle activity using intramuscular electrodes. The results provide information that allows us to propose effective exercises for enhancing deep trunk muscle activity and improve the complex coordination of trunk muscle activity that is important during sports.
Article
Background: The association between voice and body posture is consensual across the scientific literature and seems to be established both ways. Any changes in normal posture can influence the mechanisms of vocal production; on the other hand, vocal rehabilitation can influence posture. Objectives: This study aimed to evaluate the postural pattern in subjects with organic voice disorders before and after speech rehabilitation, using computerised dynamic posturography (CDP). Methods: In this prospective cohort study, 21 patients affected by dysphonia caused by benign vocal fold lesions, never treated with speech therapy/vocal training, were submitted to a posturographic analysis using CDP before and after vocal rehabilitation/therapy. Each patient underwent an accurate voice and ear, nose, and throat (ENT) anamnesis, a general ENT examination, a rigid and flexible laryngoscopy, a videolaryngostroboscopy, an acoustic voice analysis including aerodynamic evaluation, and a perceptual evaluation of voice using the Grade, Roughness, Breathiness, Asthenia, and Strain (GRBAS) scale and the Voice Handicap Index (VHI) questionnaire, before and after vocal therapy. Fifteen healthy age- and sex-matched volunteers were also submitted to a posturographic analysis on the day of recruitment and 4 weeks later. Results: All patients showed an improvement in voice quality after vocal training. The VHI decreased in all subjects, and the GRBAS scale showed a decrease in all parameters in each vowel (/a/, /i/, /e/) and in spontaneous speech (p < 0.001 for all). Posturographic results showed an improvement in equilibrium score, in conditions 2-6 and composite score. Strategic analysis results showed an improvement in conditions 1-6. Conclusions: The posturographic analysis showed a significant difference in the visual, vestibular, and proprioceptive component of posture after voice therapy. These results showed that dysphonic patients changed their postural patterns after an effective voice treatment, with an improvement in postural performance. It seems like modifications of breathing pattern and voice production techniques led to objective and measurable postural changes.
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Study Design Cross sectional, laboratory study. Background Individuals with low back pain have impaired activation of multifidus during postural adjustments and increased activity of the erector spinae musculature during walking. However, it is unclear if these alterations in muscle activity are evident during locomotion in individuals with a history of low back pain when they are between symptomatic episodes. Objectives To compare paraspinal muscle activity in young healthy individuals and young individuals with a history of low back pain during walking turns. Methods 14 asymptomatic individuals with a history of low back pain and 14 controls performed 90° walking turns at both self-selected and fast speed. The duration and amplitude of activity in the deep fibers of multifidus and the lumbar and thoracic longissimus were quantified using intramuscular electromyography. Results There was a significant speed by group interaction for the duration of multifidus activity (p = .013). Duration of activity increased from the self-selected to the fast locomotor speed in the controls, but decreased in the individuals with a history of low back pain (p = .003). Self-selected speed was the same in both groups (p = .719). There was a trend towards a significant association between group and the direction of change in the duration of deep multifidus activity (χ(2) = .058). Duration of thoracic longissimus activity and amplitude of multifidus and thoracic longissimus activity increased similarly in both groups from the self-selected to faster speed. Conclusion Even between symptomatic episodes, young individuals with a history of low back pain demonstrated altered recruitment of the deep fibers of lumbar multifidus in response to changing locomotor speed during walking turns. J Orthop Sports Phys Ther, Epub 21 Mar 2016. doi:10.2519/jospt.2016.6230.
Chapter
Surface electromyography (sEMG) is typically applied in musculoskeletal physical therapy for the assessment of disturbed motor control and for monitoring change with rehabilitation. This chapter explores fundamental methods of EMG assessment as a means of evaluating neuromuscular impairment in patients with musculoskeletal disorders with a focus on two of the most common musculoskeletal complaints, namely, low back pain and neck pain. Distinct modifications of the sEMG signal can be identified during sustained voluntary or electrically elicited muscle contractions, and the analysis of myoelectric manifestations of muscle fatigue can provide important information about physiological changes evolving in the muscle. The amplitude of the surface EMG can be estimated by a scheme of demodulation, smoothing, and relinearization. An approach to monitoring the amplitude of activity of muscles with sEMG is to measure tuning curves. The chapter further reviews some of the most frequently applied analyses in musculoskeletal physical therapy research.
Article
Purpose : This study purposed to analyze how dynamic stabilization exercise on an unstable surface, and static stabilization exercise on muscle strength and endurance. Methods : For this study we sampled 9 people for the unstable surface dynamic stabilization exercise group, 9 for the stable surface static stabilization exercise group, and 9 for the control group. In order to examine muscle strength and endurance, we measured changes in the maximal voluntary isometric contraction (MVIC) using a dynamometer before, 3 weeks after, and 6 weeks after the experiment. Results : First, with regard to change in muscle strength, flexion strength showed a significant change in interaction by time (p
Article
Background: Previous reviews relating to the effects of respiratory muscle training (RMT) after stroke tend to focus on only one type of training (inspiratory or expiratory muscles) and most based the results on poor-quality studies (PEDro score ≤4). Objectives: With this systematic review and meta-analysis, we aimed to determine the effects of RMT (inspiratory or expiratory muscle training, or mixed) on exercise tolerance, respiratory muscle function and pulmonary function and also the effects depending on the type of training performed at short- and medium-term in post-stroke. Methods: Databases searched were MEDLINE, PEDro, CINAHL, EMBASE and Web of Science up to the end of April 2020. The quality and risk of bias for each included study was examined by the PEDro scale (including only high-quality studies) and Cochrane Risk of Bias tool. Results: Nine studies (463 patients) were included. The meta-analysis showed a significant increase in exercise tolerance [4 studies; n = 111; standardized mean difference [SMD] = 0.65 (95% confidence interval 0.27-1.04)]; inspiratory muscle strength [9 studies; n = 344; SMD = 0.65 (0.17-1.13)]; inspiratory muscle endurance [3 studies; n = 81; SMD = 1.19 (0.71-1.66)]; diaphragm thickness [3 studies; n = 79; SMD = 0.9 (0.43-1.37)]; and peak expiratory flow [3 studies; n = 84; SMD = 0.55 (0.03-1.08)] in the short-term. There were no benefits on expiratory muscle strength and pulmonary function variables (forced expiratory volume in 1 sec) in the short-term. Conclusions: The meta-analysis provided moderate-quality evidence that RMT improves exercise tolerance, diaphragm thickness and pulmonary function (i.e., peak expiratory flow) and low-quality evidence for the effects on inspiratory muscle strength and endurance in stroke survivors in the short-term. None of these effects are retained in the medium-term. Combined inspiratory and expiratory muscle training seems to promote greater respiratory changes than inspiratory muscle training alone.
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The human spinal column, devoid of musculature, is incapable of carrying normal physiologic loads. In an in vitro experiment, the effect of simulated intersegmental muscle forces on spinal instability was investigated. Intact and sequentially injured fresh lumbar functional spinal units were subjected to three-dimensional biomechanical tests with increasing muscle forces. With the application of muscle forces, range of motion (ROM) increased and neutral zone (NZ) decreased in flexion loading, while both ROM and NZ decreased in extension loading. In lateral bending, ROM and NZ were unaffected by the application of the muscle forces. In axial rotation, ROM decreased significantly, while NZ decrease was statistically insignificant. It was concluded that the action of the intersegmental muscle forces is to maintain or decrease intervertebral motions after injury, with the exception of the flexion ROM, which increased with the application of muscle forces. In addition, the study suggested that Neutral Zone is a better indicator of spinal instability than Range of Motion.
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Mechanical constraints appear to require that locomotion and breathing be synchronized in running mammals. Phase locking of limb and respiratory frequency has now been recorded during treadmill running in jackrabbits and during locomotion on solid ground in dogs, horses, and humans. Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running. Flying birds have independently achieved phase-locked locomotor and respiratory cycles. This hints that strict locomotor-respiratory coupling may be a vital factor in the sustained aerobic exercise of endothermic vertebrates, especially those in which the stresses of locomotion tend to deform the thoracic complex.
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Unexpected ventral and dorsal perturbations and expected, self-induced ventral perturbations were delivered to the trunk by suddenly loading a vest strapped to the torso. Six male subjects were measured for intra-abdominal pressure (IAP) and intra-muscular electromyography of the transversus abdominis (TrA), obliquus internus abdominis (OI), obliquus externus abdominis (OE) and rectus abdominis (RA) muscles. Erector spinae (ES) activity was recorded using surface electromyography. Displacements of the trunk and head were registered using a video-based system. Unexpected ventral loading produced activity in TrA, OI, OE and RA, and an IAP increase well in advance of activity from ES. Expected ventral loading produced pre-activation of all muscles and an increased IAP prior to the perturbation. The TrA was always the first muscle active in both the unexpected and self-loading conditions. Of the two ventral loading conditions, forward displacement of the trunk was significantly reduced during the self-loading. Unexpected dorsal loading produced coincident activation of TrA, OI, OE, RA and ES. These results indicate a response of the trunk muscles to sudden expected and unexpected ventral loadings other than the anticipated immediate extensor torque production through ES activation. It is suggested that the increase in IAP is a mechanism designed to improve the stability of the trunk through a stiffening of the whole segment.
Article
Study design: This study investigated the influence of five different muscle groups on the monosegmental motion (L4-L5) during pure flexion/extension, lateral bending, and axial rotation moments. Objectives. The results showed and compared the effect of different muscle groups acting in different directions on the stability of a single motion segment to find loading conditions of in vitro experiments that simulate more physiologically reasonable loads. Summary of Background Data. In spine biomechanics research, most in vitro experiments have been carried out without applying muscle forces, even though these forces stabilize the spinal column in vivo. Methods. Seven human lumbosacral spines were tested in a spine tester that allows simulation of up to five symmetrical muscle forces. Changing pure flexion/extention, lateral binding, and axial rotation moments up to +/-3.75 Nm were applied without muscle forces, with different muscle groups and combinations. The three-dimensional monosegmental motion was determined using an instrumented spatial linkage system. Results. Simulated muscle forces were found to strongly influence load-deformation characteristics. Muscle action generally increased the range of motion and the natural zone of the motion segments. This was most evident for flexion and extension. After five pairs of symmetrical, constant muscle forces were applied (80 N per pair) the range of motion decreased about 93% in flexion and 85% in extension. The total natural zone for flexion and extension was decreased by 83% muscle action. The multifluids muscle group had the strongest influence. Conclusion. This experiment showed the important of including at least some of the most important muscle groups in invitro experiments in lumbar spine specimens.
Article
Study Design: The contribution of transversus abdominis to spinal stabilization was evaluated indirectly in people with and without low back pain using an experimental model identifying the coordination of trunk muscles in response to a disturbance to the spine produced by arm movement. Objectives: To evaluate the temporal sequence of trunk muscle activity associated with arm movement, and to determine if dysfunction of this parameter was present in patients with low back pain. Summary of Background Data: Few studies have evaluated the motor control of trunk muscles or the potential for dysfunction of this system in patients with low back pain. Evaluation of the response of trunk muscles to limb movement provides a suitable model to evaluate this system. Recent evidence indicates that this evaluation should include transversus abdominis. Methods: While standing, 15 patients with low back pain and 15 matched control subjects performed rapid shoulder flexion, abduction, and extension in response to a visual stimulus. Electromyographic activity of the abdominal muscles, lumbar multifidus, and the contralateral deltoid was evaluated using fine‐wire and surface electrodes. Results: Movement in each direction resulted in contraction of trunk muscles before or shortly after the deltoid in control subjects. The transversus abdominis was invariably the first muscle active and was not influenced by movement direction, supporting the hypothesized role of this muscle in spinal stiffness generation. Contraction of transversus abdominis was significantly delayed in patients with low back pain with all movements. Isolated differences were noted in the other muscles. Conclusions: The delayed onset of contraction of transversus abdominis indicates a deficit of motor control and is hypothesized to result in inefficient muscular stabilization of the spine.
Article
The purpose of this study was to examine the three-dimensional low back loads, spinal motions, and trunk muscular activity during gait. Specific objectives involved assessment of the effects of walking speed, and arm swing on spinal loads, lumbar spine motion, and muscular activation. An in vivo modeling experiment using five male participants. Thirty walking trials were performed by each participant yielding five repeats of each condition (3 walking cadences x 2 arm swing conditions). Walking is often prescribed as a rehabilitation task for individuals with low back injuries. However, there are few studies which have examined the joint loading, spinal motions, and muscular activity present when walking. Additionally, the majority of studies examining spine loading during gait have used an inverse dynamics model, commencing at the cranial aspect of the body, approach which does not include the impulsive phases of gait (i.e. heel strikes and toe offs). Low back joint forces (bone on bone) and moments were determined using an anatomically complex three-dimensional model (detailing 54 muscles and the passive structures acting at the low back) during three walking cadences and with free arm swing or restricted arm swing. In order to assess the influence of the transient factors such as heel contact on the joint forces a bottom up (from the feet to the lumbar spine) rigid link segment analyses approach was used as one input to the three-dimensional anatomic model. Lumbar spine motion and trunk muscle activation levels were also recorded to assist in partitioning forces amongst the active and passive tissues of the low back. Net joint anterior-posterior shear loading was the only variable significantly affected by walking cadence (fast versus slow P < 0.0003). No variable was significantly affected by the arm swing condition. Trends demonstrated an increase in all variables with increased walking cadence. Similarly, most variables, with the exception of axial twist and lateral bend lumbar spine motion and lateral joint shear, demonstrated increasing trends caused by the restriction of normal arm swing. Tissue loading during walking appears to be below levels caused by many specific rehabilitation tasks, suggesting that walking is a wise choice for general back exercise and rehabilitation programs. Slow walking with restricted arm swing produced more 'static' lumbar spine loading and motion patterns, which could be detrimental for certain injuries and tissues. Fast walking produced a more cyclic loading pattern.
Article
The co-ordination between respiratory and postural functions of the diaphragm was investigated during repetitive upper limb movement. It was hypothesised that diaphragm activity would occur either tonically or phasically in association with the forces from each movement and that this activity would combine with phasic respiratory activity. Movements of the upper limb and ribcage were measured while standing subjects performed repetitive upper limb movements 'as fast as possible'. Electromyographic (EMG) recordings of the costal diaphragm were made using intramuscular electrodes in four subjects. Surface electrodes were placed over the deltoid and erector spinae muscles. In contrast to standing at rest, diaphragm activity was present throughout expiration at 78 +/- 17% (mean +/- s.d.) of its peak inspiratory magnitude during repeated upper limb movement. Bursts of deltoid and erector spinae EMG activity occurred at the limb movement frequency (approximately 2.9 Hz). Although the majority of diaphragm EMG power was at the respiratory frequency (approximately 0.4 Hz), a peak was also present at the movement frequency. This finding was corroborated by averaged EMG activity triggered from upper limb movement. In addition, diaphragm EMG activity was coherent with ribcage motion at the respiratory frequency and with upper limb movement at the movement frequency. The diaphragm response was similar when movement was performed while sitting. In addition, when subjects moved with increasing frequency the peak upper limb acceleration correlated with diaphragm EMG amplitude. These findings support the argument that diaphragm contraction is related to trunk control. The results indicate that activity of human phrenic motoneurones is organised such that it contributes to both posture and respiration during a task which repetitively challenges trunk posture.
Article
Studies on the proactive control of gait have shown that proximal (hip/trunk) muscles are the primary contributors to balance control, while studies on reactive balance control during perturbed gait, examining only activity in distal (leg/thigh) muscles, have shown that these muscles are important in compensating for a gait disturbance. This study tested the hypothesis that proximal muscles are also primary contributors to reactive balance control during perturbed gait. Thirty-three young adults participated in a study in which an anterior slip was simulated at heel strike by the forward displacement of a force plate on which they walked. Surface electromyographic data were recorded from bilateral leg, thigh, hip and trunk muscles. Kinematic data were collected on joint angle changes in response to the perturbation. The results did not support the hypothesis that the proximal muscles contribute significantly to balance control during perturbed gait. The proximal muscles did not demonstrate more consistent activation, earlier onset latency, longer burst duration or larger burst magnitude than distal muscles. Moreover, although proximal postural activity was often present in the first slip trial, it tended to adapt away in later trials. By contrast, the typical postural responses exhibited by young adults consisted of an early (90-140 ms), high-magnitude (4-9 times muscle activity during normal walking) and relatively long duration (70-200 ms) activation of bilateral anterior leg muscles as well as the anterior and posterior thigh muscles. Thus, postural activity from bilateral leg and thigh muscles and the coordination between the two lower extremities were the key to reactive balance control and were sufficient for regaining balance within one gait cycle. The adaptive attenuation of proximal postural activity over repeated trials suggests that the nervous system overcompensates for a novel balance threat in the first slip trial and fine-tunes its responses with experience.
Article
Evaluation of trunk movements, trunk muscle activation, intra-abdominal pressure and displacement of centres of pressure and mass was undertaken to determine whether trunk orientation is a controlled variable prior to and during rapid bilateral movement of the upper limbs. Standing subjects performed rapid bilateral symmetrical upper limb movements in three directions (flexion, abduction and extension). The results indicated a small (0.4-3.3 degrees) but consistent initial angular displacement between the segments of the trunk in a direction opposite to that produced by the reactive moments resulting from limb movement. Phasic activation of superficial trunk muscles was consistent with this pattern of preparatory motion and with the direction of motion of the centre of mass. In contrast, activation of the deep abdominal muscles was independent of the direction of limb motion, suggesting a non-direction specific contribution to spinal stability. The results support the opinion that feedforward postural responses result in trunk movements, and that orientation of the trunk and centre of mass are both controlled variables in relation to rapid limb movements.
Article
The weight of the upper part of the trunk is partially transmitted to the pelvis via the vertebral column. If the muscle walls around the abdominal cavity are contracted, a high pressure can be generated within the cavity (greater than 200 mmHg). The abdominal space can them transmit part of weight to, e.g., the upper part of the body, Intra-abdominal pressure recordings have been performed during locomotion and other natural movements with intragastric pressure recordings. With each step, there is a phasic variation in pressure, with its peak coinciding with that of the peak vertical force exerted by the leg against the ground. The peak values increase progressively with the speed of walking/running up to a mean of 38 mmHg and with trough values of 16 mmHg. The phasic variations with each step is due to a phasic activation of the abdominal muscles, with an EMG activity starting 50 ms or more before foot contact. If an extra load is put on the back, the posture changes and at the highest speed of running the pressure values are significantly higher than without this additional load. After a jump down from a moderate height of 0.4 m, the average increase is 89 mmHg and can often exceed 100 mmHg. These pressure changes are large and will presumably act to unload the spine under the prevailing biomechanical conditions and, in addition, there will no doubt be an effect on the circulatory system.
Article
1. The incidence of entrainment of breathing frequency by the rhythm of exercise was detected by a cross-correlation of the two frequencies. 2. During moderate, steady-state exercise on a bicycle ergometer at 50 rev/min, eight of fifteen volunteers (53%) showed entrainment when pedalling speed was kept constant with a metronome, and three of fifteen volunteers (20%) showed entrainment when pedalling speed was kept constant with a speedometer. 3. At 70 rev/min, in a second group of fifteen volunteers, the results were nine of fifteen (60%) and five of fifteen (33%) respectively. 4. During moderate, steady state exercise on a treadmill, in a third group of fifteen volunteers, eight of 15 volunteers (53%) showed entrainment while walking, and twelve of fifteen volunteers (80%) showed entrainment while running. 5. It is concluded that the rhythm of exercise is likely to affect the rhythm of breathing and that this controlling factor must be considered during studies of breathing pattern in exercise.
Article
The aim was to investigate possible relationships between activities of the individual muscles of the ventrolateral abdominal wall and the development of pressure within the abdominal cavity. Intra-muscular activity was recorded bilaterally from transversus abdominis, obliquus internus, obliquus externus and rectus abdominis with fine-wire electrodes guided into place using real-time ultrasound. Intra-abdominal pressure was measured intragastrically using a micro tip pressure transducer. Six males were studied during loading and movement tasks with varied levels of intra-abdominal pressure. During both maximal voluntary isometric trunk flexion and extension, transversus abdominis activity and intra-abdominal pressure remained constant, while all other abdominal muscles showed a marked reduction during extension. When maximal isometric trunk flexor or extensor torques were imposed upon a maximal Valsalva manoeuvre, transversus abdominis activity and intra-abdominal pressure remained comparable within and across conditions, whereas obliquus internus, obliquus externus and rectus abdominis activities either markedly increased (flexion) or decreased (extension). Trunk twisting movements showed reciprocal patterns of activity between the left and right sides of transversus abdominis, indicating an ability for torque development. During trunk flexion--extension, transversus abdominis showed less distinguished changes of activity possibly relating to a general stabilizing function. In varied pulsed Valsalva manoeuvres, changes in peak intra-abdominal pressure were correlated with mean amplitude electromyograms of all abdominal muscles, excluding rectus abdominis. It is concluded that the co-ordinative patterns shown between the muscles of the ventrolateral abdominal wall are task specific based upon demands of movement, torque and stabilization. It appears that transversus abdominis is the abdominal muscle whose activity is most consistently related to changes in intra-abdominal pressure.
Article
Breathing frequency has been shown to depend on metabolic demand, and also to be affected by stepping frequency during walking. To assess the influence of stepping frequency on breathing frequency, we recorded the timing of breathing and stepping in ten naive subjects walking on a treadmill. Five of the subjects showed periods of breathing in rhythm with their stepping (rhythmical entrainment); five subjects never showed rhythmical entrainment. In all subjects, respiratory frequency tended to increase with increases in estimated metabolic rate (EMR) produced by increases in walking speed or treadmill inclination. Breathing frequency was also affected by stepping frequency independent of EMR, both during rhythmical entrainment and in the absence of rhythmical entrainment. The dependence of breathing frequency on stepping frequency may reflect an excitatory influence of voluntary movement on the respiratory center. We conclude that stepping importantly influences breathing frequency during walking whether or not the two are rhythmically linked. Such lability of respiratory frequency probably reflects the small metabolic cost of departure from mechanically optimal frequencies.
Article
We used a high-resolution ultrasound to make electrical recordings from the transversus abdominis muscle in humans. The behavior of this muscle was then compared with that of the external oblique and rectus abdominis in six normal subjects in the seated posture. During voluntary efforts such as expiration from functional residual capacity, speaking, expulsive maneuvers, and isovolume "belly-in" maneuvers, the transversus in general contracted together with the external oblique and the rectus abdominis. In contrast, during hyperoxic hypercapnia, all subjects had phasic expiratory activity in the transversus at ventilations between 10 and 18 l/min, well before activity could be recorded from either the external oblique or the rectus abdominis. Similarly, inspiratory elastic loading evoked transversus expiratory activity in all subjects but external oblique activity in only one subject and rectus abdominis activity in only two subjects. We thus conclude that in humans 1) the transversus abdominis is recruited preferentially to the superficial muscle layer of the abdominal wall during breathing and 2) the threshold for abdominal muscle recruitment during expiration is substantially lower than conventionally thought.
Article
It has been suggested that the muscles of the anterolateral abdominal wall increase the stability of the lumbar region of the vertebral column by tensing the thoracolumbar fascia and by raising intra-abdominal pressure. In this report these new mechanisms are reviewed and their contribution to vertebral stability assessed. The thoracolumbar fascia consists of two principal layers of dense fibrous tissue that attach the abdominal muscles to the vertebral column. Each of these layers was dissected in fresh and fixed material and samples chosen for light and scanning electron microscopy to study the arrangement of the component fibers. Computed axial tomography in volunteers showed the changes in spatial organization that occur during flexion of the back and during the Valsalva maneuver. The fascia was then tensed experimentally in isolated unfixed motion segments. The results suggested that the stabilizing action of the thoracolumbar fascia is less than had been thought previously but was consistent with calculations based on the more accurate structural and mechanical information that had been derived from the current study. Abdominal muscle contraction was simulated in whole cadavers in both the flexed and lateral bending positions to compare the stabilizing effect of the thoracolumbar fascia and intra-abdominal pressure mechanisms. These definitive experiments showed that the resistance to bending in the sagittal plane offered by the abdominal muscles acting through fascial tension was of a similar magnitude to that offered by a raised intra-abdominal pressure, both being relatively small in the fully flexed position. The stabilizing influence of the middle layer of the thoracolumbar fascia in lateral bending was clearly demonstrated and warrants further study in vivo.
Article
An electromyographic study of the lower extremity muscles was undertaken in order to compare jogging, running, and sprinting. The study demonstrated that as the speed of gait increased, the support phase decreased, from 620 msec for walking to 260 msec for jogging to 220 msec for running to 140 msec for sprinting. The electromyographic data demonstrated that all muscle groups except the hip flexor and adductor longus were active during foot descent, floor contact, and midsupport. There was absence of muscle function during the late toe-off phase except that demonstrated by the adductor longus and the abdominal muscles during sprinting. The main muscle group that appears to increase the speed of gait is that of the hip flexors, which is closely linked to the knee extensors in order to propel the body forward in the line of progression. There was little or no activity in the gastrocnemius or in the intrinsic muscles of the foot about the time of toe-off, leading the authors to conclude that push-off per se does not appear to occur.
Article
The myoelectric activity of the mm. multifidi and the mm. iliocostales lumborum of six subjects was recorded during walking. The subjects walked on a treadmill as well as on a fixed walkway. On the treadmill, recordings were made at two different speeds and with a varying loading of the spine. There was almost no difference in myoelectric activity time between the treadmill and the fixed walkway. Related to unloaded walking, both the multifidi and the iliocostales showed an increase in activity time when the subjects carried a load of 5 kg in front of the trunk and a decrease of activity time with a load of 5 kg on the back. A load on the lateral aspect of the body shortened the muscle activity time of the multifidi on the homolateral side. In three subjects the same pattern was found for the iliocostales, but in the other three subjects there was no activity registered at all. On the side contralateral to the load, the multifidi showed no increase of activity time while the iliocostales muscles demonstrated an increase. It is concluded that during walking the iliocostalis muscle has a more important function in lateral bending than the multifidus. It was remarkable that the multifidi muscles of the left side were active for longer periods than were those of the right side in all situations except during lateral loading.
Article
Selected variables were measured to examine differences in overground and treadmill running at sprinting speeds of maximal effort. Five college-varsity sprinters volunteered to run 100-yd sprints in both overground and treadmill running conditions. After a minimum of 10 training sessions on the treadmill, the subjects were filmed (75 fps) sprinting 100 yd and expired respiratory gases were collected during an 18-min recovery period. The oxygen debt of the overground condition, means = 47.86 ml X kg-1, was 36% greater than the treadmill running condition, means = 30.64 ml X kg-1. Regardless of individual running style, the major biomechanical differences between treadmill and overground running conditions occurred during the support phase and were observed in the supporting leg. During treadmill running, the leg of the supporting lower extremity was less erect at contact (means = 83.9 vs 88.3 deg) and moved through a greater range of motion (means = 60.6 vs 54.5 deg) with a faster overall angular velocity (means = 566.36 vs 478.07 deg X s-1). The thigh of the supporting lower extremity was more erect at contact (means = 67.1 vs 61.1 deg) and moved with a slower overall angular velocity (means = 435.14 vs 528.77 deg X s-1). Data suggest that the moving treadmill belt reduces the energy requirements of the runner by bringing the supporting leg back under the body during the support phase of running.
Article
The function of lumbar back muscles was studied by relating their activity patterns to trunk movements in 7 healthy adult males during normal walking (1.0-2.5 m/s) and running (2.0-7.0 m/s) on a treadmill. The movements of the trunk in the sagittal and frontal planes were recorded with a Selspot optoelectronic system using infrared light emitting diodes as markers. The electromyographic (EMG) activity from the two main portions of the lumbar erector spinae muscles (Multifidus and Longissimus) was recorded bilaterally with intramuscular wire electrodes. The angular displacements of the trunk showed regular oscillations, but their shape, magnitude and relation to the step cycle were different in the two planes (sagittal and frontal) and varied with speed and mode of progression. The EMG pattern in both muscles showed a bilateral cocontraction with two main bursts of activity per step cycle starting just before each foot was placed on the ground. Relating the EMG to the movements of the trunk indicated that the main function of the lumbar erector spinae muscles is to restrict excessive trunk movements. During walking this restricting action is most evident for movements in the frontal plane, whereas in running the lumbar back muscles mainly control the movements in the sagittal plane.
Article
A biomechanical study of 13 runners which consisted of 2 male sprinters, 5 experienced joggers, and 6 elite long-distance runners were studied. We obtained hip, knee, and ankle joints motions in the sagittal plane and electromyographic data from specific muscle groups. As the speed of gait increased, the length of stance phase progressively decreased from 62% for walking to 31% for running and to 22% for sprinting. The sagittal plane motion increased as the speed of gait increased. Generally speaking, the body lowers its center of gravity with the increased speed by increasing flexion of the hips and knees and magnifying dorsiflexion at the ankle joint. Electromyographic activity about the knee demonstrated increased activity in the quadricep muscle group and hamstring group with increased speed. Mus cle function about the ankle joint demonstrated that the pos terior calf musculature which normally functions during the midstance phase in walking became a late swing phase muscle and was active through the first 80% of stance phase, as compared to 15% in walking. Beside the changes in the electromyographic activity of the muscles, the anterior compartment muscles of the calf undergo a concentric contracture at the time of initial floor contact during running and sprinting but undergo an eccentric contrac tion during walking.
Article
This study investigated the influence of five different muscle groups on the monosegmental motion (L4-L5) during pure flexion/extension, lateral bending, and axial rotation moments. The results showed and compared the effect of different muscle groups acting in different directions on the stability of a single motion segment to find loading conditions for in vitro experiments that simulate more physiologically reasonable loads. In spine biomechanics research, most in vitro experiments have been carried out without applying muscle forces, even though these forces stabilize the spinal column in vivo. Seven human lumbosacral spines were tested in a spine tester that allows simulation of up to five symmetrical muscle forces. Changing pure flexion/extension, lateral bending, and axial rotation moments up to +/- 3.75 Nm were applied without muscle forces, with different muscle groups and combinations. The three-dimensional monosegmental motion was determined using an instrumented spatial linkage system. Simulated muscle forces were found to strongly influence load-deformation characteristics. Muscle action generally decreased the range of motion and the neutral zone of the motion segments. This was most evident for flexion and extension. After five pairs of symmetrical, constant muscle forces were applied (80 N per pair), the range of motion decreased about 93% in flexion and 85% in extension. The total neutral zone for flexion and extension was decreased by 83% muscle action. The multifidus muscle group had the strongest influence. This experiment showed the importance of including at least some of the most important muscle groups in in vitro experiments on lumbar spine specimens.
Article
Just as in running, the two-joint muscles acting at the hip and at the knee work to transfer energy efficiently between body segments. This can be seen in Figure 12. The powers at the hip and knee are overlaid to show that when power is generated at the hip, it is absorbed at the knee and vice versa. For example, a concentric contraction of the hamstrings proximally at the hip is coupled with an eccentric contraction at the knee just prior to initial contact in terminal swing. The rectus femoris functions in a similar way but in an opposite direction in initial swing. For the three conditions discussed, the relative contribution of work occurring at each joint is different. Figure 13 shows that the muscles about the ankle are the most important source of work in walking and that the knee musculature does not significantly contribute to the work done for walking. In walking, the knee is felt to be important for the smoothing of gait. The quadriceps are a much more important source of energy at the knee in both running and sprinting, as can be seen in Figure 13. Finally, the hip musculature becomes the dominant source of work in sprinting in our group of untrained subjects with significant contributions from both the hip flexors and extensors. One would expect that the relative importance of each of the muscle groups about each of these joints in terms of sources of energy might change with training. The intent of this work was to evaluate the three conditions of walking, running, and sprinting. I hope that it will stimulate further interest and research in this area in order to come to a greater understanding of human locomotion. As more knowledge and experience are gained, the motion analysis lab will be able to offer insight into training strategies, injury prevention, and the treatment of pathologic running and sprinting conditions.
Article
1. The purpose of the present study was to analyse the incidence and type of coordination between breathing rhythm and leg movements during running and to assess the effect of co-ordination on the running efficiency, as well as to compare the results with those found during cycling. 2. The experiments were carried out on thirty-four untrained volunteers exercising at two work loads (60 and 80% of subject's physical work capacity 170) on a treadmill. In addition nineteen of the subjects exercised at the same two work loads on a bicycle ergometer. The subjects were running at both work loads in three different modes in randomized order: with normal arm movements, without arm movements and with breathing paced by an acoustic signal which was triggered by the leg movement. 3. Respiratory variables, oxygen uptake and leg movements were continuously recorded and evaluated on-line. The degree of co-ordination was expressed as a percentage of inspirations and/or expirations starting in the same phase of the step or pedalling cycle. 4. The average degree of co-ordination was higher during running (up to 40%) than during cycling (about 20%) during both work loads. The difference in the degree of co-ordination between running and cycling is probably not due to the lack of arm movements during cycling since the degree of co-ordination during running with and without arm movements was the same. 5. The degree of co-ordination during running increased slightly but not significantly with increasing work load and could be increased significantly by paced breathing. 6. The co-ordination between breathing and running rhythms occurred in three different patterns: (a) breathing was co-ordinated all the time with the same phase of step, (b) co-ordination switched suddenly from one phase of step to another and (c) co-ordination ensued alternatively once on the right and once on the left leg movement. During cycling the pattern described in (a) occurred almost exclusively. 7. During running with a high degree of co-ordination, oxygen uptake for a given work load was slightly but significantly lower than during running with weak co-ordination.
Article
The contribution of transversus abdominis to spinal stabilization was evaluated indirectly in people with and without low back pain using an experimental model identifying the coordination of trunk muscles in response to a disturbances to the spine produced by arm movement. To evaluate the temporal sequence of trunk muscle activity associated with arm movement, and to determine if dysfunction of this parameter was present in patients with low back pain. Few studies have evaluated the motor control of trunk muscles or the potential for dysfunction of this system in patients with low back pain. Evaluation of the response of trunk muscles to limb movement provides a suitable model to evaluate this system. Recent evidence indicates that this evaluation should include transversus abdominis. While standing, 15 patients with low back pain and 15 matched control subjects performed rapid shoulder flexion, abduction, and extension in response to a visual stimulus. Electromyographic activity of the abdominal muscles, lumbar multifidus, and the surface electrodes. Movement in each direction resulted in contraction of trunk muscles before or shortly after the deltoid in control subjects. The transversus abdominis was invariably the first muscle active and was not influenced by movement direction, supporting the hypothesized role of this muscle in spinal stiffness generation. Contraction of transversus abdominis was significantly delayed in patients with low back pain with all movements. Isolated differences were noted in the other muscles. The delayed onset of contraction of transversus abdominis indicates a deficit of motor control and is hypothesized to result in inefficient muscular stabilization of the spine.
Little consensus exists in the literature regarding methods for determination of the onset of electromyographic (EMG) activity. The aim of this study was to compare the relative accuracy of a range of computer-based techniques with respect to EMG onset determined visually by an experienced examiner. Twenty-seven methods were compared which varied in terms of EMG processing (low pass filtering at 10, 50 and 500 Hz), threshold value (1, 2 and 3 SD beyond mean of baseline activity) and the number of samples for which the mean must exceed the defined threshold (20, 50 and 100 ms). Three hundred randomly selected trials of a postural task were evaluated using each technique. The visual determination of EMG onset was found to be highly repeatable between days. Linear regression equations were calculated for the values selected by each computer method which indicated that the onset values selected by the majority of the parameter combinations deviated significantly from the visually derived onset values. Several methods accurately selected the time of onset of EMG activity and are recommended for future use.
Article
Because the structure of the spine is inherently unstable, muscle activation is essential for the maintenance of trunk posture and intervertebral control when the limbs are moved. To investigate how the central nervous system deals with this situation the temporal components of the response of the muscles of the trunk were evaluated during rapid limb movement performed in response to a visual stimulus. Fine-wire electromyography (EMG) electrodes were inserted into transversus abdominis (TrA), obliquus internus abdominis (OI) and obliquus externus abdominis (OE) of 15 subjects under the guidance of real-time ultrasound imaging. Surface electrodes were placed over rectus abdominis (RA), lumbar multifidus (MF) and the three parts of deltoid. In a standing position, ten repetitions of shoulder flexion, abduction and extension were performed by the subjects as fast as possible in response to a visual stimulus. The onset of TrA EMG occurred in advance of deltoid irrespective of the movement direction. The time to onset of EMG activity of OI, OE, RA and MF varied with the movement direction, being activated earliest when the prime action of the muscle opposed the reactive forces associated with the specific limb movement. It is postulated that the non-direction-specific contraction of TrA may be related to the control of trunk stability independent of the requirement for direction-specific control of the centre of gravity in relation to the base of support.
Article
Treadmills are often used in research to analyse kinematic and physiological variables. The success of transfering the results to overground running depends on the comparability of the values between the two situations. The aim of the present study was to compare the kinematics and muscle activities in overground and treadmill running. Ten male physical education students with experience in treadmill running were asked to run with a speed of 4.0 and 6.0 m/s both overground and on a Woodway treadmill. The 3D-kinematics of the limbs were studied using a two camera video tracking system. Additionally the surface EMG of six lower limb muscles and the pattern of ground contact of the right foot was registered. Both the activities of the leg muscles and several kinematic variables showed systematic changes from overground to treadmill running. On the treadmill the subjects favoured a type of running that provided them with a higher level of security. The swing amplitude of the leg, the vertical displacement and the variance in vertical and horizontal velocity were lower in treadmill running. The angle between shoe sole and ground at foot impact was also lower and the forward lean of the upper body was higher in running on the treadmill compared with the overground mode. Most of the subjects reduced their step length and increased stride frequency in treadmill running. Furthermore, the contact time in treadmill running was shorter than for overground running. The above mentioned kinematic variables were significantly different (p < 0.05). The EMG patterns of the leg muscles were generally similar between overground and treadmill modes, but some minor differences could consistently be identified.
Article
Timing of foot contact events provides important information for gait studies. The aim of the study is to validate the use of kinematic data, collected at 50 Hz to define foot contact events during gait initiation. Simultaneous kinetic and kinematic data recordings of four discrete foot contact events were made for normal adults. Raters were asked to estimate the timing of the events from kinematic data curves and these timings were compared with those derived from the kinetic data. For the four events, between 88 and 98% of all ratings were accurate to within 0.03 s. Inter-rater reliability was extremely high, reflecting the precision of the definitions used.