The maximal rate of rise in muscle force [rate development (RFD)] has important functional consequences as it determines the that can be generated early phase contraction (0–200 ms). present study examined effect resistance training on contractile RFD and efferent motor outflow (“neural drive”) during contraction. Contractile (slope force-time curve), impulse (time-integrated force), electromyography (EMG) signal amplitude (mean average voltage), EMG EMG-time curve) were determined (1-kHz...

In human pennate muscle, changes in anatomical cross‐sectional area (CSA) or volume caused by training inactivity may not necessarily reflect the change physiological CSA, and thereby maximal contractile force, since a simultaneous muscle fibre pennation angle could also occur. Eleven male subjects undertook 14 weeks of heavy‐resistance strength lower limb muscles. Before after CSA quadriceps femoris were assessed use magnetic resonance imaging (MRI), (θ p ) was measured vastus lateralis...

Combined V-wave and Hoffmann (H) reflex measurements were performed during maximal muscle contraction to examine the neural adaptation mechanisms induced by resistance training. The H-reflex can be used assess excitability of spinal α-motoneurons, while also reflecting transmission efficiency (i.e., presynaptic inhibition) in Ia afferent synapses. Furthermore, reflects overall magnitude efferent motor output from α-motoneuron pool because activation descending central pathways. Fourteen male...

Conventionally, the hamstring:quadriceps strength ratio is calculated by dividing maximal knee flexor (hamstring) moment extensor (quadriceps) measured at identical angular velocity and contraction mode. The agonist-antagonist relationship for extension flexion may, however, be better described more functional ratios of eccentric hamstring to concentric quadriceps moments (extension), (flexion). We compared conventional isokinetic hamstring: examined their relation joint angle velocity. Peak...

Despite full voluntary effort, neuromuscular activation of the quadriceps femoris muscle appears inhibited during slow concentric and eccentric contractions. Our aim was to compare maximal contractions, hypothesizing that inhibition diminishes with resistance training. In 15 men, pretraining electromyographic activity muscles [vastus medialis (VM), vastus lateralis (VL), rectus (RF)] 17–36% lower fast (30 240°/s) contractions compared After 14 wk heavy training, reduced for VL VM completely...

1. We investigated the effect of a long‐term stretching regimen on tissue properties and stretch tolerance human skeletal muscle. 2. Resistance to was measured as torque (in N m) offered by hamstring muscle group during passive knee extension while electromyographic (EMG) activity, joint angle velocity were continuously monitored standardized manoeuvre. Seven healthy subjects tested before after 3 week training period using two separate protocols. Protocol 1 consisted slow at 0.087 rad s‐1...

To examine stiffness, energy, and passive torque in the dynamic static phases of a stretch maneuver human hamstring muscle vivo we used test-retest protocol repeated stretches protocol. Resistance to was defined as (in newton-meters) offered by group during knee extension measured using an isokinetic dynamometer with modified thigh pad. In 13 uninjured subjects, passively extended predetermined final position (0.0875 rad/ sec, phase) where it remained stationary for 90 seconds (static...

This study investigated isokinetic peak‐ and angle‐specific hamstring/quadriceps strength ratios (conventional H/Q ratio) obtained during concentric eccentric muscle contraction examined the influence of joint angular velocity effect gravity correction on these ratios. Also, a ‘functional’ ratio was defined by calculating hamstring relative to quadriceps (H eee /Q eon representative for knee extension) flexion). The calculated based peak moment 50 o ‐moment (0 = full at velocities 30, 120...

The aims of this study were to examine the release speed ball in maximal instep kicking with preferred and non-preferred leg relate biomechanical differences observed during action. Seven skilled soccer players performed place kicks nonpreferred leg; their movements filmed at 400 Hz. inter-segmental kinematics kinetics derived. A coefficient restitution between foot was calculated rate force development hip flexors knee extensors measured using a Kin-Com dynamometer. Higher speeds achieved...

The aim of the present study was to quantify amount antagonist coactivation and resultant moment force generated by hamstring muscles during maximal quadriceps contraction in slow isokinetic knee extension. net joint at electromyographic (EMG) signals vastus medialis, lateralis, rectus femoris (quadriceps) biceps caput longum semitendinosus (hamstrings) were obtained 16 male subjects extension (KinCom, ROM 90–10°, 30° · s −1 ). Two types performed: [1] concentric contractions [2] eccentric...

1. The objective of the study was to evaluate functional effects reflexes on muscle mechanics during natural voluntary movements. excitability H (Hoffmann) reflex used as a measure central component stretch reflex. 2. We recorded EMG, ground reaction forces and in soleus humans while landing from downward jump, drop jumping hopping. movements were also by high‐speed cinematography. 3. EMG pattern adapted motor task. When anterior tibial showed preinnervation alternating activity after touch...

Cross‐sectional area, stiffness, viscoelastic stress relaxation, stretch tolerance and EMG activity of the human hamstring muscle group were examined in endurance‐trained athletes with varying flexibility. Subjects defined as tight ( n =10) or normal =8) based on a clinical toe‐touch test. area was computed from magnetic resonance imagining (MRI) images. Torque (Nm) offered by group, electromyographic (EMG) activity, knee joint angle velocity continuously monitored during two standardized...

The purpose of this study was (1) to evaluate the reproducibility a new method measuring passive resistance stretch in human hamstring muscle group, vivo , using test re‐test protocol and 2) examine effect repeated stretches. Passive offered by group during knee extension measured 10 subjects as flexion moment (Nm) KinCom dynamometer. passively extended at 5 deg/s final position where it remained stationary for 90 s (static phase). EMG also measured. included 2 tests (tests 1 administered h...

The short term effect of static and cyclic stretch paradigms on stiffness maximal joint range motion was examined in 12 recreational athletes. To assess flexibility, resistance to were measured using a dynamometer during passive the hamstring muscle group point pain. recorded torque-angle curve allowed for identification calculation muscle-tendon energy. Three flexibility assessments (stretch 1 -3), each 10 min apart, administered leg. A 90 s stretches performed after second left right side,...

Recordings from video surveillance systems are used as evidence crime scenes. It would be useful to perform comparisons between disguised perpetrators and suspects based on their gait. We applied functional anatomical biomechanical knowledge analyze the gait of perpetrators, recorded video. Using a structured checklist, which addresses single body segments during gait, we were able give statement concerning patterns. Characteristic parameters were, e.g., varus instability in knee at heel...

The aim of the study was to investigate distribution net joint moments in lower extremities during walking on high-heeled shoes compared with barefooted at identical speed. Fourteen female subjects walked 4 km/h across three force platforms while they were filmed by five digital video cameras operating 50 frames/second. Both and (heel height: 9 cm) recorded. Net calculated 3D inverse dynamics. EMG recorded from eight leg muscles. knee extensor moment peak first half stance phase doubled when...

The present study sought to investigate the role of EMG activity during passive static stretch. and resistance were measured stretching human skeletal muscle in eight neurologically intact control subjects six spinal cord-injured (SCI) with complete motor loss. Resistance stretch offered by hamstring muscles knee extension was defined as torque (Nm). passively extended at 5 degrees/s a predetermined final position, where it remained stationary for 90 s (static phase) while force integrated...

1. The objective of the study was to investigate amplitude and modulation human soleus Hoffmann (H) reflex during walking running at different speeds. 2. EMGs were recorded with surface electrodes from soleus, medial lateral head gastrocnemius, vastus lateralis anterior tibial muscles. H while on a treadmill 4.5 km h-1 8, 12 15 h-1. 3. amplitudes M wave normalized maximal elicited by supramaximal stimulus just after compensate for movements recording relative nerve muscle fibres. intensity...

The present study investigated the effects of three different strength training regimes on isokinetic profile knee extensors (quadriceps, Q) and flexors (hamstrings, H) if increases in were accompanied by an enhanced performance during a more complex leg movement, soccer kick. Twenty‐two elite players performed 12 weeks (three times per week) at either high resistance (HR group: 4 sets, 8 reps, 8RM loading), low (LR 24 24RM loaded kicking movements (LK 16 16RM loading) while one group served...