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Temporal biomechanical and physiological responses to physical activity vary between individual hamstrings components as well as between exercises, suggesting that hamstring muscles operate differently, and over different lengths, between tasks. Nevertheless, the force-length properties of these muscles have not been thoroughly investigated. The present review examines the factors influencing the hamstrings’ force-length properties and relates them to in vivo function. A search in four databases was performed for studies that examined relations between muscle length and force, torque, activation, or moment arm of hamstring muscles. Evidence was collated in relation to force-length relationships at a sarcomere/fiber level and then moment arm-length, activation-length, and torque-joint angle relations. Five forward simulation models were also used to predict force-length and torque-length relations of hamstring muscles. The results show that, due to architectural differences alone, semitendinosus (ST) produces less peak force and has a flatter active (contractile) fiber force-length relation than both biceps femoris long head (BFlh) and semimembranosus (SM), however BFlh and SM contribute greater forces through much of the hip and knee joint ranges of motion. The hamstrings’ maximum moment arms are greater at the hip than knee, so the muscles tend to act more as force producers at the hip but generate greater joint rotation and angular velocity at the knee for a given muscle shortening length and speed. However, SM moment arm is longer than SM and BFlh, partially alleviating its reduced force capacity but also reducing its otherwise substantial excursion potential. The current evidence, bound by the limitations of electromyography techniques, suggests that joint angle-dependent activation variations have minimal impact on force-length or torque-angle relations. During daily activities such as walking or sitting down, the hamstrings appear to operate on the ascending l

Biceps femoris long head (BFlh) fascicle length (Lf), fascicle angle (FA), and muscle thickness (MT) were assessed at rest and during dynamic contractions using B-mode ultrasound imaging. The assessments were performed in men and women with no previous hamstring strain injury. Volunteers visited the laboratory for two separate data collection sessions (Day 1 and Day 2) relating to two independent projects, seven days apart at the same time of day for test-retest measurements of the static assessments. For the dynamic assessments, familiarization with the isokinetic concentric and eccentric knee flexion exercises were performed on Day 1. On Day 2, BFlh Lf, FA and MT were assessed in real time using two serially aligned ultrasound devices whilst performing consecutive concentric and eccentric knee flexions at 30°/s and 180°/s. To acquire images at rest, ultrasound imaging was performed using extended field-of-view (EFOV) and static image acquisition sequences of four single images acquired in-series along the muscle. From these images, Lf was assessed using seven methods: EFOV, Collage, manual linear extrapolation, and using four different trigonometric equations, and then FA and MT were measured in EFOV, Collage, and Single images. Lf, FA and MT measured on Days 1 and 2 were not different (p > 0.05) for any method, reliabilities were very high (ICC: 0.91-0.98), and correlations were strong ( ≥ 0.84). Significant correlations (p < 0.05; r=0.67-0.98) were found between EFOV and the other measurement techniques for Lf, FA and MT. The Collage method had the highest reliability for Lf, and highest rank order and correlation with EFOV. The Collage method can therefore be recommended for use if the methodology presented herein is followed. For assessments during dynamic contractions, participants performed consecutive concentric and eccentric contractions at 30°/s and 180°/s whilst in vivo muscle function was recorded using two in-series transducers. At 30°/s both submaxima

Pedestrian injuries related to the use of cell phone have increased in relation to the total number of pedestrian accidents. The aim of this study was to compare kinematic and electromyographic variables in both lower limbs at facing an obstacle, with (WC) and without (WoC) the use of a cell phone. Ten young women were evaluated, while walking and facing an obstacle WC and WoC. A 3D biomechanical model was used to evaluate the lower limb kinematics (hip, knee, ankle in the sagittal plane, together with «toe clearance»). At the same time, the electromyographic (EMG) activity was registered in the following muscles: tibialis anterior (TA), gastrocnemius medialis (GM), rectus femoris (RF) and biceps femoris (BF). The mean EMG amplitude of each muscle and the muscular coactivation percentage between: TA-GM and RA-BF were calculated. The strategy for both lower limbs considering the first (P1) and the second step (P2) were analyzed when crossing the obstacle, comparing between gait WC vs WoC. According to results, the gait WC increase the toe clearance, hip flexion, and the GM amplitude, observed both in P1 as P2 when the person crossed the obstacle. Furthermore, the P2 revealed an increase in the knee and ankle flexion. On the other hand, the TA amplitude and the muscular coactivation between TA-GM also increased WC in the P2. In conclusion, the kinematic and electromyographic variables in the lower limbs are modified when crossing an obstacle WC. These findings could indicate a protective strategy during the dual-task evaluated, minimizing the risk of falling., Las lesiones de transeúntes relacionadas al uso de teléfono celular han aumentado en relación con el total de accidentespeatonales. El objetivo de este estudio fue comparar variables cinemáticas y electromiográficas de ambas extremidades inferiores alenfrentar un obstáculo, con (CC) y sin (SC) el uso de celular. Diez mujeres jóvenes fueron evaluadas, las cuales caminaron y enfrentaronun obstáculo CC y SC. Con un modelo biomecánico 3D se evaluó la cinemática de extremidad inferior (plano sagital de cadera, rodilla,tobillo, junto al «toe clearance»). Al mismo tiempo se registró la actividad electromiográfica (EMG) de los siguientes músculos: tibialanterior (TA), gastrocnemio medial (GM), recto anterior (RA) y bíceps femoral (BF). Se calculó la amplitud EMG promedio de cadamúsculo, y el porcentaje de coactivación muscular entre: TA-GM y RA-BF. Se analizó la estrategia de ambas piernas, considerando unprimer (P1) y segundo paso (P2) al cruzar el obstáculo, comparando entre una marcha CC vs CS. Según los resultados, la marcha CCincrementa el toe clearance, flexión de cadera, y la amplitud del GM, observado tanto en P1 como P2 al cruzar el obstáculo. Adicionalmente,el P2 reveló un incremento en la flexión de rodilla y tobillo. Por otro lado, la amplitud del TA y coactivación muscular entre TA-GMtambién aumentó CC en el P2. En conclusión, las variables cinemáticas y electromiográficas en las extremidades inferiores se modificanal cruzar un obstáculo CC. Estos hallazgos podrían indicar una estrategia protectora durante la tarea dual evaluada, minimizando el riesgode caída

Objectives: Hamstring injuries are common and can now be accurately diagnosed. In addition, novel surgical indications have been introduced. However, evidence-based guidelines on the hamstring injuries in management of top-level athletes are missing. Methods: The management methods and outcomes of treatment are classically based on relatively small case series. We discuss a novel concept based on the fact that each tendon of the hamstrings muscle should be managed in an individual fashion. Furthermore, suitable indications for hamstring surgery in athletes are introduced. Results: The present study introduces modern treatment principles for hamstring injury management. Typical clinical and imagining findings as well as surgical treatment are presented based on a critical review of the available literature and personal experience. Conclusions: Hamstring injuries should not be considered to be all equal given the complexity of this anatomical region: The three separate tendons are different, and this impacts greatly on the decision-making process and outcomes in athletes.

Introduction This study examined the effects of 24 wk of daily static stretching of the plantarflexors (unilateral 4 x 60-s stretching, whereas the contralateral leg served as a control; n = 26) on joint range of motion (ROM), muscle-tendon unit morphological and mechanical properties, neural activation, and contractile function. Methods Torque-angle/velocity was obtained in passive and active conditions using isokinetic dynamometry, whereas muscle-tendon morphology and mechanical properties were examined using ultrasonography. Results After the intervention, ROM increased (stretching, +11 degrees +/- 7 degrees; control, 4 degrees +/- 8 degrees), and passive torque (stretching, -10 +/- 11 N center dot m; control, -7 +/- 10 N center dot m) and normalized EMG amplitude (stretching, -3% +/- 6%; control, -3% +/- 4%) at a standardized dorsiflexion angle decreased. Increases were seen in passive tendon elongation at a standardized force (stretching, +1.3 +/- 1.6 mm; control, +1.4 +/- 2.1 mm) and in maximal passive muscle and tendon elongation. Angle of peak torque shifted toward dorsiflexion. No changes were seen in tendon stiffness, resting tendon length, or gastrocnemius medialis fascicle length. Conformable changes in ROM, passive dorsiflexion variables, tendon elongation, and angle of peak torque were observed in the nonstretched leg. Conclusions The present findings indicate that habitual stretching increases ROM and decreases passive torque, altering muscle-tendon behavior with the potential to modify contractile function.

Introduction This study examined the effects of 24 wk of daily static stretching of the plantarflexors (unilateral 4 x 60-s stretching, whereas the contralateral leg served as a control; n = 26) on joint range of motion (ROM), muscle-tendon unit morphological and mechanical properties, neural activation, and contractile function. Methods Torque-angle/velocity was obtained in passive and active conditions using isokinetic dynamometry, whereas muscle-tendon morphology and mechanical properties were examined using ultrasonography. Results After the intervention, ROM increased (stretching, +11 degrees +/- 7 degrees; control, 4 degrees +/- 8 degrees), and passive torque (stretching, -10 +/- 11 N center dot m; control, -7 +/- 10 N center dot m) and normalized EMG amplitude (stretching, -3% +/- 6%; control, -3% +/- 4%) at a standardized dorsiflexion angle decreased. Increases were seen in passive tendon elongation at a standardized force (stretching, +1.3 +/- 1.6 mm; control, +1.4 +/- 2.1 mm) and in maximal passive muscle and tendon elongation. Angle of peak torque shifted toward dorsiflexion. No changes were seen in tendon stiffness, resting tendon length, or gastrocnemius medialis fascicle length. Conformable changes in ROM, passive dorsiflexion variables, tendon elongation, and angle of peak torque were observed in the nonstretched leg. Conclusions The present findings indicate that habitual stretching increases ROM and decreases passive torque, altering muscle-tendon behavior with the potential to modify contractile function.

Most suckling kids are raised on farms for cheese production, and many goat farmers rear kids with milk replacers. The aim of this work was to study the influence of the use of milk replacers on the color of four muscles. A total of 246 suckling kids of eight breeds were slaughtered to achieve carcasses of 5 kg. The color of the biceps femoris, semimembranosus, semitendinosus, and longissimus thoracis muscles was measured with a spectrophotometer, and CIELab coordinates were registered. In addition, the pH of longissimus thoracis was measured. The effect of the rearing system (RS) on the color of the studied muscles is strongly modulated by breed. In general terms, there are two groups of kids according to the color of meat. The first group has great lightness and hue angle including Malagueña, Palmera, and Tinerfeña fed natural and artificial milk. The second group with great redness includes Retinta, Payoya, and Verata fed natural and artificial milk together with Florida fed natural milk and Cabra del Guadarrama fed milk replacers. Hence, farms should consider selecting a breed and RS together. Most of the kid meat with high pH comes from kids raised on milk replacers. Because artificial RSs use very early weaning, which might induce a high pH and dark meat, two artificial rearing strategies can be proposed. The first strategy is to choose less sensitive breeds that produce meat with a normal pH. The second strategy is to restrict suckling of natural milk but minimize separation from the mother.

Most suckling kids are raised on farms for cheese production, and many goat farmers rear kids with milk replacers. The aim of this work was to study the influence of the use of milk replacers on the color of four muscles. A total of 246 suckling kids of eight breeds were slaughtered to achieve carcasses of 5 kg. The color of the biceps femoris, semimembranosus, semitendinosus, and longissimus thoracis muscles was measured with a spectrophotometer, and CIELab coordinates were registered. In addition, the pH of longissimus thoracis was measured. The effect of the rearing system (RS) on the color of the studied muscles is strongly modulated by breed. In general terms, there are two groups of kids according to the color of meat. The first group has great lightness and hue angle including Malagueña, Palmera, and Tinerfeña fed natural and artificial milk. The second group with great redness includes Retinta, Payoya, and Verata fed natural and artificial milk together with Florida fed natural milk and Cabra del Guadarrama fed milk replacers. Hence, farms should consider selecting a breed and RS together. Most of the kid meat with high pH comes from kids raised on milk replacers. Because artificial RSs use very early weaning, which might induce a high pH and dark meat, two artificial rearing strategies can be proposed. The first strategy is to choose less sensitive breeds that produce meat with a normal pH. The second strategy is to restrict suckling of natural milk but minimize separation from the mother.

Measurement of muscle specific contractile properties in response to resistance training (RT) can provide practitioners valuable information regarding physiological status of individuals. Field based measurements of such contractile properties within specific muscle groups, could be beneficial when monitoring efficacy of training or rehabilitation interventions. Tensiomyography (TMG) quantifies contractile properties of individual muscles via an electrically stimulated twitch contraction and may serve as a viable option in the aforementioned applications. Thus, aims of this study were; (i) to investigate the potential use of TMG to quantify training adaptations and differences, in response to exercise specific lower limb RT; and (ii) investigate any associations between TMG parameters and accompanying muscle architectural measures. Non-resistance trained male participants (n = 33) were randomly assigned to 1 of 3 single-exercise intervention groups (n = 11 per group); back squat (BS), deadlift (DL), or hip thrust (HT). Participants completed a 6-week linearized training program (2× per week), where the assigned exercise was the sole method of lower body training. Pre- and post-intervention testing of maximal dynamic strength was assessed by one repetition maximum (1RM) of BS, DL, and HT. Radial muscle belly displacement (Dm) and contraction time (Tc) were obtained via TMG from the rectus femoris (RF) and vastus lateralis (VL) pre- and post-intervention, alongside muscle architectural measures (pennation angle and muscle thickness). All three groups displayed significant increases all 1RM strength tests (p < 0.001; pη2 = 0.677–0.753). Strength increases were accompanied by significant overall increases in RF muscle thickness (p < 0.001, pη2 = 0.969), and pennation angle (p = 0.007, pη2 = 0.220). Additionally, an overall reduction in RF Dm (p < 0.001, pη2 = 0.427) was observed. Significant negative relationships were observed betwe

Most suckling kids are raised on farms for cheese production, and many goat farmers rear kids with milk replacers. The aim of this work was to study the influence of the use of milk replacers on the color of four muscles. A total of 246 suckling kids of eight breeds were slaughtered to achieve carcasses of 5 kg. The color of the biceps femoris, semimembranosus, semitendinosus, and longissimus thoracis muscles was measured with a spectrophotometer, and CIELab coordinates were registered. In addition, the pH of longissimus thoracis was measured. The effect of the rearing system (RS) on the color of the studied muscles is strongly modulated by breed. In general terms, there are two groups of kids according to the color of meat. The first group has great lightness and hue angle including Malagueña, Palmera, and Tinerfeña fed natural and artificial milk. The second group with great redness includes Retinta, Payoya, and Verata fed natural and artificial milk together with Florida fed natural milk and Cabra del Guadarrama fed milk replacers. Hence, farms should consider selecting a breed and RS together. Most of the kid meat with high pH comes from kids raised on milk replacers. Because artificial RSs use very early weaning, which might induce a high pH and dark meat, two artificial rearing strategies can be proposed. The first strategy is to choose less sensitive breeds that produce meat with a normal pH. The second strategy is to restrict suckling of natural milk but minimize separation from the mother.

Most suckling kids are raised on farms for cheese production, and many goat farmers rear kids with milk replacers. The aim of this work was to study the influence of the use of milk replacers on the color of four muscles. A total of 246 suckling kids of eight breeds were slaughtered to achieve carcasses of 5 kg. The color of the biceps femoris, semimembranosus, semitendinosus, and longissimus thoracis muscles was measured with a spectrophotometer, and CIELab coordinates were registered. In addition, the pH of longissimus thoracis was measured. The effect of the rearing system (RS) on the color of the studied muscles is strongly modulated by breed. In general terms, there are two groups of kids according to the color of meat. The first group has great lightness and hue angle including Malagueña, Palmera, and Tinerfeña fed natural and artificial milk. The second group with great redness includes Retinta, Payoya, and Verata fed natural and artificial milk together with Florida fed natural milk and Cabra del Guadarrama fed milk replacers. Hence, farms should consider selecting a breed and RS together. Most of the kid meat with high pH comes from kids raised on milk replacers. Because artificial RSs use very early weaning, which might induce a high pH and dark meat, two artificial rearing strategies can be proposed. The first strategy is to choose less sensitive breeds that produce meat with a normal pH. The second strategy is to restrict suckling of natural milk but minimize separation from the mother.

Most suckling kids are raised on farms for cheese production, and many goat farmers rear kids with milk replacers. The aim of this work was to study the influence of the use of milk replacers on the color of four muscles. A total of 246 suckling kids of eight breeds were slaughtered to achieve carcasses of 5 kg. The color of the biceps femoris, semimembranosus, semitendinosus, and longissimus thoracis muscles was measured with a spectrophotometer, and CIELab coordinates were registered. In addition, the pH of longissimus thoracis was measured. The effect of the rearing system (RS) on the color of the studied muscles is strongly modulated by breed. In general terms, there are two groups of kids according to the color of meat. The first group has great lightness and hue angle including Malagueña, Palmera, and Tinerfeña fed natural and artificial milk. The second group with great redness includes Retinta, Payoya, and Verata fed natural and artificial milk together with Florida fed natural milk and Cabra del Guadarrama fed milk replacers. Hence, farms should consider selecting a breed and RS together. Most of the kid meat with high pH comes from kids raised on milk replacers. Because artificial RSs use very early weaning, which might induce a high pH and dark meat, two artificial rearing strategies can be proposed. The first strategy is to choose less sensitive breeds that produce meat with a normal pH. The second strategy is to restrict suckling of natural milk but minimize separation from the mother.

Most suckling kids are raised on farms for cheese production, and many goat farmers rear kids with milk replacers. The aim of this work was to study the influence of the use of milk replacers on the color of four muscles. A total of 246 suckling kids of eight breeds were slaughtered to achieve carcasses of 5 kg. The color of the biceps femoris, semimembranosus, semitendinosus, and longissimus thoracis muscles was measured with a spectrophotometer, and CIELab coordinates were registered. In addition, the pH of longissimus thoracis was measured. The effect of the rearing system (RS) on the color of the studied muscles is strongly modulated by breed. In general terms, there are two groups of kids according to the color of meat. The first group has great lightness and hue angle including Malagueña, Palmera, and Tinerfeña fed natural and artificial milk. The second group with great redness includes Retinta, Payoya, and Verata fed natural and artificial milk together with Florida fed natural milk and Cabra del Guadarrama fed milk replacers. Hence, farms should consider selecting a breed and RS together. Most of the kid meat with high pH comes from kids raised on milk replacers. Because artificial RSs use very early weaning, which might induce a high pH and dark meat, two artificial rearing strategies can be proposed. The first strategy is to choose less sensitive breeds that produce meat with a normal pH. The second strategy is to restrict suckling of natural milk but minimize separation from the mother.

The aim of this study was to evaluate the effect of an industrial exoskeleton on muscle activity, perceived musculoskeletal effort, measured and perceived contact pressure at the trunk, thighs and shoulders, and subjective usability for simple sagittal plane lifting and lowering conditions. Twelve male participants lifted and lowered a box of 7.5 kg and 15 kg, respectively, from mid-shin height to waist height, five times, both with and without the exoskeleton. The device significantly reduced muscle activity of the Erector Spinae (12%-15%) and Biceps Femoris (5%). Ratings of perceived musculoskeletal effort in the trunk region were significantly less with the device (9.5%-11.4%). The measured contact pressure was highest on the trunk (91.7 kPa-93.8 kPa) and least on shoulders (47.6 kPa-51.7 kPa), whereas pressure was perceived highest on the thighs (35-44% of Max LPP). Six of the users rated the device usability as acceptable. The exoskeleton reduced musculoskeletal loading on the lower back and assisted with hip extensor torque during lifting and lowering. Contact pressures fell below the Pain Pressure Threshold. Perceived pressure was not exceptionally high, but sufficiently high to cause discomfort if used for long durations.

peer-reviewed, In the shot put, the athlete's muscles are responsible for generating the impulses to move the athlete and project the shot into the air. Information on phasic muscle activity is lacking for the glide shot put event and therefore important technical information for coaches is not currently available. This study provides an electromyography (EMG) analysis of the muscle activity of the legs during shot put. Fifteen right-handed Irish national level shot putters performed six maximum effort throws using the glide shot put technique. EMG records of eight bilateral lower limb muscles (rectus femoris, biceps femoris, medial- and lateral-gastrocnemius) were obtained during trials. Analysis using smooth EMG linear envelopes revealed patterns of muscle activity across the phases of the throw and compare men and women performers. The results showed that the preferred leg rectus femoris, the preferred leg biceps femoris and the non-preferred leg biceps femoris play important roles in the glide technique, with the total duration of high volumes of activity between 34 and 53% of the throw cycle. A comprehensive understanding of movement and muscle activation patterns for coaches could be helpful to facilitate optimal technique throughout each of the key phases of the event., ACCEPTED, peer-reviewed

The aims of this study were to investigate the effects of a 4-week intervention of static stretching (SS) on muscle hardness of the semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) muscles. Shear elastic modulus was measured by using ultrasound shear wave elastography as the index of muscle hardness. Thirty healthy men (age 22.7 ± 2.2 years) volunteered for this study and were randomly assigned to the SS intervention group (n = 15) or the control group (n = 15). Participants in the SS intervention group received a 4-week stretch intervention for the hamstrings of their dominant leg. Shear elastic moduli of the hamstrings were measured at initial evaluation and after 4 weeks in both groups at a determined angle. In all muscles, the shear elastic modulus decreased significantly after SS intervention. The percentage change in the shear elastic modulus from the value at initial evaluation to after 4 weeks intervention was greatest in the SM. These results suggest that SS intervention has chronic effects on reducing hardness of the hamstring muscle components, especially the SM muscle.

This thesis describes, for the first time, the forces involved in the Nordic hamstring exercise, its reliability and the biomechanical effects of extra loading during the movement. The results provide practitioners with valuable information to enhance hamstring injury prevention and rehabilitation programs.

Drying is the lengthiest and the most energy consuming step during the production of dry-cured ham, affecting also the curing process and consequently product quality. In order to manage the drying process, it is quite interesting to establish the complexity of model needed. For that purpose, pork meat cylinders (Biceps femoris and Semimembranosus muscles) were dehydrated under forced convection conditions (25°C and air velocity 0.6±0.1, 2.0±0.1 and 2.8±0.1m/s). Experimental drying kinetics were modelled by means of 4 diffusion models: model 1 (not considering shrinkage and no external resistance), model 2 (considering shrinkage and no external resistance), model 3 (not considering shrinkage and considering external resistance) and model 4 (considering both shrinkage and external resistance). From the effective diffusivity values identified, it was concluded that when external resistance was negligible (air velocity 2.0±0.1 and 2.8±0.1m/s), the results obtained for De with the four models were the same. Nevertheless, when external resistance was not negligible (0.6±0.1m/s) the De identified was influenced by the model due to the fact that models 1 and 2 neglect that resistance and for that reason they do not describe experimental conditions properly. The effect of shrinkage did not influence the identified De values for the drying conditions considered. In order to model water losses in meat curing chambers, external resistance must be considered. © 2011 Elsevier B.V.

[EN] Ultrasonic velocity was used to characterise the differences in composition and texture of Biceps Femoris muscles from four batches of pigs of different genetics (Iberian and Iberian x Duroc) and feeding systems ("montanera" and concentrate). Significant differences (p<0.05) were found for the ultrasonic velocity in samples with different genetics and feeding systems. These differences were dependent on the temperature of the measurements and were related to the intramuscular fat content (IMF) of the samples and, therefore, to the meat quality. The ultrasonic velocities at 0 and 20 degrees C were related to the IMF (R=0.77 and 0.65, respectively). A discriminant analysis, including ultrasonic velocity at temperatures from 0 to 20 degrees C, allowed 87.0% of the samples to be correctly classified in the batches. Therefore, ultrasonics could be useful in the characterisation and differentiation of B. lemons muscles of Iberian pigs with different genetics and from different feeding systems. (C) 2011 Elsevier Ltd. All rights reserved

Drying is the lengthiest and the most energy consuming step during the production of dry-cured ham, affecting also the curing process and consequently product quality. In order to manage the drying process, it is quite interesting to establish the complexity of model needed. For that purpose, pork meat cylinders (Biceps femoris and Semimembranosus muscles) were dehydrated under forced convection conditions (25°C and air velocity 0.6±0.1, 2.0±0.1 and 2.8±0.1m/s). Experimental drying kinetics were modelled by means of 4 diffusion models: model 1 (not considering shrinkage and no external resistance), model 2 (considering shrinkage and no external resistance), model 3 (not considering shrinkage and considering external resistance) and model 4 (considering both shrinkage and external resistance). From the effective diffusivity values identified, it was concluded that when external resistance was negligible (air velocity 2.0±0.1 and 2.8±0.1m/s), the results obtained for De with the four models were the same. Nevertheless, when external resistance was not negligible (0.6±0.1m/s) the De identified was influenced by the model due to the fact that models 1 and 2 neglect that resistance and for that reason they do not describe experimental conditions properly. The effect of shrinkage did not influence the identified De values for the drying conditions considered. In order to model water losses in meat curing chambers, external resistance must be considered. © 2011 Elsevier B.V.

Theoretical mechanical benefits of biarticular muscles include reduced displacements and force potentiating shifts in linear velocities during multi-joint coupled motions. A cadaveric model was developed to compute muscle kinematics of biceps femoris (BFL and BFS) during four classes of coupled knee and hip joint motion, as well as running and walking gait (Six subjects, Vicon Motion Analysis). The examples of the classes of motion were: KEHE-jump (knee extension and hip extension), KFHF-tuck (knee flexion and hip flexion), KFHE-kick (knee flexion and hip extension), and KEHF-paw (knee extension and hip flexion). BFL peak and mean velocity shifts relative to BFS were seen in all four coupling classes (p<0.05) and the majority of the gait subclasses (p<0.05). Muscle displacements were larger in BFL for both KFHE-paw and KEHF-kick (p<0.05), smaller in KFHF-tuck (p<0.05), but not significantly different in KEHE-jump or during most of the running gait subclasses, except for during KFHE-late mid stance and KEHF-mid swing, where they were larger for BFL (p<0.05). The mechanical benefits associated with BFL velocity shift relative to BFs were identified in KFHF, KEHF motions, and certain subclasses of gait. In contrast, there were potential mechanical detriments due to velocity shift relative to BFs in the KEHE-jump, KFHE-paw, and the majority of KEHE and KFHE subclasses in both gait cycles. The possible mechanical benefits associated with displacement conservation of BFL relative to BFs would be realized in KFHF-tuck jump, but not during KEHE-jump and the gait cycle subclasses. The findings of this study reveal both mechanical benefits and detriments of biarticular muscles, and have immediate implications for neural control of biarticular muscles during movement.

Theoretical mechanical benefits of biarticular muscles include reduced displacements and force potentiating shifts in linear velocities during multi-joint coupled motions. A cadaveric model was developed to compute muscle kinematics of biceps femoris (BFL and BFS) during four classes of coupled knee and hip joint motion, as well as running and walking gait (Six subjects, Vicon Motion Analysis). The examples of the classes of motion were: KEHE-jump (knee extension and hip extension), KFHF-tuck (knee flexion and hip flexion), KFHE-kick (knee flexion and hip extension), and KEHF-paw (knee extension and hip flexion). BFL peak and mean velocity shifts relative to BFS were seen in all four coupling classes (p<0.05) and the majority of the gait subclasses (p<0.05). Muscle displacements were larger in BFL for both KFHE-paw and KEHF-kick (p<0.05), smaller in KFHF-tuck (p<0.05), but not significantly different in KEHE-jump or during most of the running gait subclasses, except for during KFHE-late mid stance and KEHF-mid swing, where they were larger for BFL (p<0.05). The mechanical benefits associated with BFL velocity shift relative to BFs were identified in KFHF, KEHF motions, and certain subclasses of gait. In contrast, there were potential mechanical detriments due to velocity shift relative to BFs in the KEHE-jump, KFHE-paw, and the majority of KEHE and KFHE subclasses in both gait cycles. The possible mechanical benefits associated with displacement conservation of BFL relative to BFs would be realized in KFHF-tuck jump, but not during KEHE-jump and the gait cycle subclasses. The findings of this study reveal both mechanical benefits and detriments of biarticular muscles, and have immediate implications for neural control of biarticular muscles during movement.

This study aims to explore the potential of evoked non-invasive surface electromyography (SEMG) analysis, in predicting meat quality traits in livestock. Evoked SEMG is a system that records, transdermally, electrical signals generated in muscle fibres upon external stimulation. These signals are reported as compound muscle action potentials (CMAP). CMAP parameters of LD correlated negatively and significantly to ultimate pH (pH 24 h) at day 61, but not at day 153 after birth, and a similar albeit positive correlation was observed for muscle glycogen content. Muscle glycogen content and pH 24 h correlated negatively in LD and BF. Negative significant correlations between CMAP parameters and shear force were found in LD at day 153 after birth, which might, in the range of the recording electrodes, reflect the combined effect of large cross-sectional area fibres and reduced perimysium content per unit volume of muscle. The fact that correlations between CMAP characteristics and quality traits of both metabolic and non metabolic origin could be established, warrants a fuller investigation of this method in terms of its potential as a predictive tool for meat quality traits in live animals.

This study aims to explore the potential of evoked non-invasive surface electromyography (SEMG) analysis, in predicting meat quality traits in livestock. Evoked SEMG is a system that records, transdermally, electrical signals generated in muscle fibres upon external stimulation. These signals are reported as compound muscle action potentials (CMAP). CMAP parameters of LD correlated negatively and significantly to ultimate pH (pH 24 h) at day 61, but not at day 153 after birth, and a similar albeit positive correlation was observed for muscle glycogen content. Muscle glycogen content and pH 24 h correlated negatively in LD and BF. Negative significant correlations between CMAP parameters and shear force were found in LD at day 153 after birth, which might, in the range of the recording electrodes, reflect the combined effect of large cross-sectional area fibres and reduced perimysium content per unit volume of muscle. The fact that correlations between CMAP characteristics and quality traits of both metabolic and non metabolic origin could be established, warrants a fuller investigation of this method in terms of its potential as a predictive tool for meat quality traits in live animals.