How Do Infants Adapt to Loading of the Limb During the Swing Phase of Stepping?

2003 ◽  
Vol 89 (4) ◽  
pp. 1920-1928 ◽  
Author(s):  
Tania Lam ◽  
Claire Wolstenholme ◽  
Jaynie F. Yang
Keyword(s):  
Sensory Input ◽  
Sagittal Plane ◽  
Sudden Change ◽  
Flexor Muscle ◽  
Human Infants ◽  
After Effects ◽  
After Effect ◽  
Leg Motion ◽  
Hip Flexion ◽  
Hip Flexor

Previous results from this laboratory have shown that human infants (<12 mo old) respond appropriately to transient changes in sensory input during stepping. We examined how infants adapted to a more enduring change in sensory input by applying load to one limb during stepping. A small weight (500–900 g) was strapped around the lower leg of infants aged 3–11 mo. Stepping with the weight on was recorded on the treadmill for a period of 0.5–3 min. The weight was then quickly detached during stepping, and the immediate response to unexpected loss of the weight recorded. Three-segment dynamic analysis of leg motion was used to estimate hip, knee, and ankle torques during swing in the sagittal plane. All infants adapted to the additional load on the leg by immediately increasing the generation of hip and knee flexor muscle torques. When the weight was removed, 7 of the 22 infants tested exhibited an after-effect (high stepping) in the first step after removal of the weight. The after-effect was manifested as an increase in toe trajectory height and hip flexion and coincided with higher hip flexor muscle torque in early swing. In an additional series of control experiments using seven infants, after-effects were shown to be unrelated to a sudden change in cutaneous input with removal of the weight. The presence of an after-effect indicates that some infants made an enduring adaptation to their stepping pattern that is revealed with the unexpected removal of the weight.

A Role for Hip Position in Initiating the Swing-to-Stance Transition in Walking Cats

2005 ◽  
Vol 94 (5) ◽  
pp. 3497-3508 ◽  
Author(s):  
D. A. McVea ◽  
J. M. Donelan ◽  
A. Tachibana ◽  
K. G. Pearson
Keyword(s):  
Hip Joint ◽  
Direct Evidence ◽  
Swing Phase ◽  
Strongly Correlated ◽  
Flexor Muscle ◽  
Extensor Muscles ◽  
Ankle Joints ◽  
Hip Flexion ◽  
Hip Flexor ◽  
Decerebrate Cats

In this investigation, we obtained data that support the hypothesis that afferent signals associated with hip flexion play a role in initiating the swing-to-stance transition of the hind legs in walking cats. Direct evidence came from observations in walking decerebrate cats. Assisting the flexion of the hip joint during swing advanced the onset of activity in ankle extensor muscles, and this advance was strongly correlated with a reduction in the duration of hip flexor muscle activity. The hip angle at the time of onset of the flexion to extension transition was similar during assisted and unassisted steps. Additional evidence for the hypothesis that sensory signals related to hip flexion are important in regulating the swing-to-stance transition came from four normal animals trained to walk in a variety of situations designed to alter the coordination of movements at the hip, knee, and ankle joints during the swing phase. Although there were exceptions in some tasks and preparations, the angle of the hip joint at the time of onset of extensor activity was generally less variable than that of the knee and ankle joints. We also found no clear relationships between the angle of the limb and body axes, or the length of the limb axis, and the time of onset of extensor activity. Finally, there were no indications that the stretching of ankle extensor muscles during swing was a factor in regulating the transition from swing-to-stance.

Proprioceptive Modulation of Hip Flexor Activity During the Swing Phase of Locomotion in Decerebrate Cats

2001 ◽  
Vol 86 (3) ◽  
pp. 1321-1332 ◽  
Author(s):  
Tania Lam ◽  
Keir G. Pearson
Keyword(s):  
Swing Phase ◽  
Burst Activity ◽  
Afferent Feedback ◽  
Medial Gastrocnemius ◽  
Flexor Muscle ◽  
Decerebrate Cat ◽  
Leg Extension ◽  
Flexor Muscles ◽  
Hip Flexion ◽  
Hip Flexor

This study examined the influence of proprioceptive input from hip flexor muscles on the activity in hip flexors during the swing phase of walking in the decerebrate cat. One hindlimb was partially denervated to remove cutaneous input and afferent input from most other hindlimb muscles. Perturbations to hip movement were applied either by 1) manual resistance or assistance to swing or by 2) resistance to hip flexion using a device that blocked hip flexion but allowed leg extension. Electromyographic recordings were made from the iliopsoas (IP), sartorius, and medial gastrocnemius muscles. When the hip was manually assisted into flexion, there was a reduction in hip flexor burst activity. Conversely, when hip flexion was manually resisted or mechanically blocked during swing, the duration and amplitude of hip flexor activity was increased. We also found some specificity in the role of afferents from individual hip flexor muscles in the modulation of flexor burst activity. If the IP muscle was detached from its insertion, little change in the response to blocking flexion was observed. Specific activation of IP afferent fibers by stretching the muscle also did not greatly affect flexor activity. On the other hand, if conduction in the sartorius nerves was blocked, there was a diminished response to blocking hip flexion. The increase in duration of the flexor bursts still occurred, but this increase was consistently lower than that observed when the sartorius nerves were intact. From these results we propose that during swing, feedback from hip flexor muscle afferents, particularly those from the sartorius muscles, enhances flexor activity. In addition, if we delayed the onset of flexor activity in the contralateral hindlimb, blocking hip flexion often resulted in the prolongation of ipsilateral flexor activity for long periods of time, further revealing the reinforcing effects of flexor afferent feedback on flexor activity. This effect was not seen if conduction in the sartorius nerves was blocked. In conclusion, we have found that hip flexor activity during locomotion can be strongly modulated by modifying proprioceptive feedback from the hip flexor muscles.

Abdominal and hip flexor muscle activation during various training exercises

1997 ◽  
Vol 75 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Eva A. Andersson ◽  
Johnny Nilsson ◽  
Zhijia Ma ◽  
Alf Thorstensson
Keyword(s):  
Muscle Activation ◽  
Flexor Muscle ◽  
Training Exercises ◽  
Hip Flexor

scholarly journals Deimatism: a neglected component of antipredator defence

2017 ◽  
Vol 13 (4) ◽  
pp. 20160936 ◽  
Author(s):  
Kate D. L. Umbers ◽  
Sebastiano De Bona ◽  
Thomas E. White ◽  
Jussi Lehtonen ◽  
Johanna Mappes ◽  
...  
Keyword(s):  
Sensory Input ◽  
Sudden Change ◽  
Fundamental Difference ◽  
Neural Mechanisms ◽  
Survival Advantage ◽  
Antipredator Defence

Deimatic or ‘startle’ displays cause a receiver to recoil reflexively in response to a sudden change in sensory input. Deimatism is sometimes implicitly treated as a form of aposematism (unprofitability associated with a signal). However, the fundamental difference is, in order to provide protection, deimatism does not require a predator to have any learned or innate aversion. Instead, deimatism can confer a survival advantage by exploiting existing neural mechanisms in a way that releases a reflexive response in the predator. We discuss the differences among deimatism, aposematism, and forms of mimicry, and their ecological and evolutionary implications. We highlight outstanding questions critical to progress in understanding deimatism.

Co-ordination of Successive Activities in an Aphid. Depression of Settling after Flight

1964 ◽  
Vol 41 (4) ◽  
pp. 805-824
Author(s):  
J. S. KENNEDY ◽  
C. O. BOOTH
Keyword(s):  
Priming Effect ◽  
Depressing Effect ◽  
After Effects ◽  
After Effect

1. Flight has a cumulative ‘priming’ effect (excitatory after-effect) on the settling responses of an aphid landing on a surface, even when the flight has been interrupted by one or more previous landings. But when the bouts of flying between landings were kept brief (1 min.) there was also an opposite, depressing or inhibitory after-effect on settling which reduced and in certain conditions regularly outweighed the priming effect. 2. Which of the two after-effects predominated depended on the kind of surface landed on each time, on the strength of the settling responses at previous landings and on the total time the aphid had been flying. 3. The depressing effect as measured on a standard host leaf was negligible when the flight had been interrupted by landings on a card, where the settling responses were weakest and soonest inhibited by flight again, greater after landings on a non-host leaf and greatest after landings on the host leaf, itself where settling responses were strongest. 4. When two successive landings were both made on the same surface, a depression of settling at the second landing was more likely after a strong previous settling response than after a weak one; it was also more likely when the two landings were made on a non-host than when they were made on a host. 5. Flight and settling are nervous antagonists and the terms ‘antagonistic induction’ and ‘antagonistic depression’ are applied, respectively, to the excitatory and the inhibitory after-effects of flight on settling. These are components in the co-ordination of flight and settling as successive activities and do not necessarily describe the sequences observed.

scholarly journals Dry matter production and nitrogen utilization in cropping systems with grass, lucerne and maize. 2. Nitrogen yield and utilization.

1986 ◽  
Vol 34 (1) ◽  
pp. 37-47
Author(s):  
J.H.J. Spiertz ◽  
L. Sibma
Keyword(s):  
Cropping Systems ◽  
Mineral Soil ◽  
Weather Conditions ◽  
N Fertilization ◽  
N Fixation ◽  
Maize Crop ◽  
After Effects ◽  
Matter Production ◽  
After Effect ◽  
Use Efficiency

The N yield and the N use efficiency were studied in a 3-year experiment with various cropping systems of Lolium perenne, Medicago sativa and maize. N yields of L. perenne and maize were about 450 and 200 kg/ha, resp. N yields of M. sativa ranged from about 400 to 600 kg/ha depending on crop age and weather conditions. N fixation rates of M. sativa were assessed in 1982 and ranged from 107 to 507 kg/ha for high (450 kg N/ha) and no N fertilization, resp. The after-effects of 1-, 2- and 3-year crops of L. perenne, M. sativa and maize on the DM and N yields of a test crop of maize were measured. Depending on the age of the preceding L. perenne crop, annually supplied with 450 kg N/ha, the N after-effects ranged from 120 to 175 kg/ha. The after-effect of a previous cropping with M. sativa was independent of the N dressing and ranged from 140 to 175 kg/ha. For comparison, the after-effect of a preceding maize crop ranged from 90 to 110 kg/ha. Mineral soil N reserves were determined in spring and autumn. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Rectus-sparing approach to the periacetabular osteotomy in adolescents preserves hip flexion strength

2020 ◽  
Vol 14 (3) ◽  
pp. 208-212
Author(s):  
David A. Podeszwa ◽  
Kirsten Tulchin-Francis ◽  
Adriana De La Rocha ◽  
DeRaan Collins ◽  
Daniel J. Sucato
Keyword(s):  
Periacetabular Osteotomy ◽  
Rectus Femoris ◽  
Harris Hip Score ◽  
Level Of Evidence ◽  
One Year ◽  
Modified Harris Hip Score ◽  
Hip Flexion ◽  
Hip Flexor ◽  
Flexion Strength ◽  
Flexor Strength

Purpose The classic periacetabular osteotomy (PAO) approach can result in hip flexor weakness in adolescents. The rectus-sparing approach (PAO-RS) preserves the origin of the rectus femoris tendon which may prevent hip flexor weakness and improve functional outcome. Methods This is a prospective analysis of adolescents treated with a PAO or PAO-RS. The PAO group included 24 hips/21 patients (18 female, meanage 16 years (sd 4)); the PAO-RS group included ten hips (eight female, mean age 16 years (sd 1)). Preoperatively, the PAO group had decreased hip flexion strength compared with the PAO-RS group (83 Nm/kg versus 102 Nm/kg). A subset of PAO patients (n = 13 hips/12 patients, nine female, mean age 15 years (sd 3)) were matched for preoperative flexion strength to the PAO-RS group. Radiographic parameters, modified Harris hip score (mHHS), isokinetic hip strength and instrumented motion analysis preoperatively, six months and one-year postoperatively were compared. Results There were no differences in preoperative deformity, postoperative correction or degree of correction between groups. Hip flexor strength decreased significantly at six months in the PAO group compared with the PAO-RS group (-35 Nm/kg versus -7 Nm/kg; p = 0.012), as did hip flexion pull-off power (1.33 W/kg PAO versus 1.76 W/kg PAO-RS; p = 0.010). Hip flexion strength improved from six months to one year in the PAO group, with no significant differences in strength at one year between groups (80 Nm/kg versus 90 Nm/kg). There were no differences between groups in mHHS any time point; both groups improved significantly postoperatively. Conclusion Preserving the rectus femoris may lead to improved short-term hip flexor strength and pull-off power. Further assessment at long-term follow-up is needed to determine if this strength leads to improved functional outcomes. Level of Evidence II

Comparison of High Resolution Gradient Echo, XBONE T1, XBONE T2, Spin Echo T1 and 3D SST1 magnetic resonance imaging sequences for imagining the canine elbow

2014 ◽  
Vol 17 (4) ◽  
pp. 587-591 ◽  
Author(s):  
Y. Zhalniarovich ◽  
Z. Adamiak ◽  
J. Głodek ◽  
P. Przyborowska ◽  
P. Holak
Keyword(s):  
High Resolution ◽  
Biceps Brachii ◽  
Sagittal Plane ◽  
Spin Echo ◽  
Gradient Echo ◽  
Flexor Muscle ◽  
Triceps Brachii ◽  
Joint Surfaces ◽  
Flexor Carpi Ulnaris ◽  
Triceps Brachii Muscle

AbstractTwenty canine elbows were examined by low-field MRI. The objective of this study was to compare five magnetic resonance sequences: High Resolution Gradient Echo in the sagittal plane, XBONE T2 in the sagittal plane, Spin Echo T1 in the sagittal plane, Spin Echo T1 in the dorsal plane and 3D SST1 and XBONE T1 in the transverse plane, and to determine which sequences have the highest diagnostic value in imagining the canine elbow. High Resolution Gradient Echo, XBONE T2 and Spin Echo T1 sequences in the sagittal plane proved to be very useful in evaluations of osseous structures such as the medial coronoid process, the anconeal process of the ulna and joint surfaces. The above sequences facilitate evaluations of radial extensor muscle of the wrist, biceps brachii muscle, triceps brachii muscle and the flexor carpi ulnaris muscle. 3D SST1 and XBONE T1 sequences in the transverse plane produce high-quality images of the medial humeral condyle and surfaces of the elbow joint. Those sequences are also useful for evaluating the surrounding muscles: extensor digitorum communis muscle, extensor carpi radialis muscle, deltoid muscle, biceps brachii muscle, pronator teres muscle and flexor carpi ulnaris muscle. The Spin Echo T1 sequence in the dorsal plane facilitates assessments of joint surfaces, medial humeral condyle, superficial digital flexor muscle, deep digital flexor muscle, triceps brachii muscle and extensor digitorum lateralis muscle. The Spin Echo T1 sequence in the sagittal plane has a short scan time, but it produces images of lower quality than High Resolution Gradient Echo and XBONE T2 sequences in the sagittal plane.

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