Reduced Shear Force Research Articles

Spinal loading and lift style in confined vertical space

The objective of this study was to investigate biomechanical loads on the lumbar spine as a function of working in a confined vertical space, consistent with baggage handling inside the baggage compartment of an airplane. Ten male subjects performed baggage handling tasks using confined (kneeling, sitting) and unconfined (stooping) lifting styles. Dependent measures of torso flexion and three-dimensional spinal loads were assessed with an electromyography-driven biomechanical model. Lifting exertions typical to airline baggage handling posed significant risk to the lumbar spine, regardless of lifting style. Statistically significant differences attributable to lift style (stooping, kneeling, sitting) were not observed for peak compressive, lateral shear, or resultant spinal loads, but lifting while kneeling decreased anterior/posterior (A/P) shear spinal loads relative to stooping (p = 0.02). Collectively, kneeling offers the greatest benefit when lifting in confined spaces because of the ability to keep the torso upright, subsequently reducing shear forces on the lumbar spine.

Meat Quality and Fatty Acid Profiles of Chinese Ningxiang Pigs Following Supplementation with N-Carbamylglutamate.

Simple SummaryN-carbamylglutamate (NCG) has been demonstrated to promote the synthesis of endogenous arginine and improve reproductive performance. In the present study, we found that dietary NCG supplementation improved meat quality of a Chinese fat-type pig by increasing muscle tenderness and Phe concentration, and optimizing fatty acid profiles in different tissues. These results provided scientific evidence for the application of NCG as a feed additive in finishing pigs.The present study evaluated the effects of dietary N-carbamylglutamate (NCG) on carcass traits, meat quality, and fatty acid profiles in the longissimus dorsi muscle and adipose tissues of Chinese Ningxiang pigs. A total of 36 castrated female pigs with a similar initial weight (43.21 ± 0.57 kg) were randomly assigned to two treatments (with six pens per treatment and three pigs per pen) and fed either a basal diet or a basal diet supplemented with 0.08% NCG for 56 days. Results showed that dietary NCG reduced shear force (p = 0.004) and increased drip loss (p = 0.044) in longissimus dorsi muscle of Ningxiang pigs. Moreover, increased levels of oleic acid (C18:1n9c) (p = 0.009), paullinic acid (C20:1) (p = 0.004), and α-linolenic acid (C18:3n3) (p < 0.001), while significant reduction in the proportions of arachidonic acid (C20:4n6) (p < 0.001) and polyunsaturated fatty acid (PUFA) (p = 0.017) were observed in the longissimus dorsi muscle of pigs fed NCG when compared with those fed the control diet. As for adipose tissues, the C20:1 (p = 0.045) proportion in dorsal subcutaneous adipose (DSA), as well as the stearic acid (C18:0) (p = 0.018) level in perirenal adipose (PA) were decreased when pigs were fed the NCG diet compared with those of the control diet. In contrast, the margaric acid (C17:0) (p = 0.043) proportion in PA were increased. Moreover, the NCG diet produced PA with a greater proportion of total PUFAs (p = 0.001) (particularly linoleic acid (C18:2n6c) (p = 0.001)) compared with those produced by the control diet. These findings suggest that dietary NCG has beneficial effects by decreasing the shear force and improving the healthfulness of fatty acid profiles, providing a novel strategy for enhancing meat quality of pigs.

A Comparision Of Spinal Loads While Lifting In Confined Vertical Space

Background: Lifting in confined vertical space is observed across several industries, including airline baggage handling, mining, construction, maintenance, and shipbuilding. However, only a few studies have investigated confined space lifting scenarios with biomechanical methods (Gallagher et al., 1988; Stalhammar et al., 1986), and fewer have quantified biomechanical loads on the intervertebral discs of the lumbar spine while lifting in confined vertical spaces using a biomechanical model (Gallagher et al., 1994; Middelton et al., 2016; Splittstoesser et al., 2007). The objective of this study was to quantify spinal loads for kneeling and sitting lifting styles in confined vertical space. This was accomplished via the replication of the baggage compartment of a narrow-bodied aircraft in a laboratory. Methods: Ten males performed airline baggage handling tasks for this study. A fully balanced design was implemented, and independent variables included lifting style (3), exertion type (4), bag weight (2), and their interactions. Lifting styles investigated included stooping, kneeling, and cross-legged sitting. In kneeling and sitting exertions, subjects were confined within 1.22 m of vertical space (i.e., the vertical constraint within a narrow-bodied airplane). However, stooping conditions were performed as a control condition in unconfined vertical space. Exertion type included loading bags from the floor to a low and high vertical heights or unloading bags from low and high vertical heights to the floor. Subjects lifted bags weighing either 14.5 kg (industry average) or 22.7 kg (95th percentile in U.S.) (Lu et al., 2018). Dependent measures included the peak torso flexion for each lift and peak spinal loads in compression, anterior/posterior (A/P) shear, and lateral shear derived from an electromyography (EMG)-driven spine model (Dufour et al., 2013; Hwang et al., 2016a, b). These spinal loads were compared to documented tolerance limits for spinal loading (Gallagher and Marras, 2012; Waters et al., 1993). Results and Discussion: Stooping, kneeling, and sitting all posed significant risk of injury to the lumbar spine via excessive compressive and A/P shear loading. Statistically significant differences attributable to lift style (stooping, kneeling, sitting) were not observed for peak compressive or lateral shear, but kneeling decreased anterior/posterior (A/P) shear spinal loads relative to stooping (p=0.02). Collectively, kneeling presented the least risk for injury to the low back when lifting in confined spaces because the torso remained more upright, subsequently reducing shear forces on the lumbar spine. However, future studies should also aim to assess the biomechanical risks associated with confined lifting scenarios to other regions of the body in which musculoskeletal disorders might be of concern (i.e., shoulders, knees). Though experimental conditions specific to baggage handling were examined, it is expected that the results of this investigation are applicable across all industries in which lifting in confined vertical spaces is observed. Conclusion: Baggage handling tasks performed in confined vertical space pose significant biomechanical risk to the lumbar spine in compression and A/P shear. From a low back loading perspective, kneeling lifting styles should be preferred to sitting when lifting in a confined vertical because of the ability to keep a more upright torso.

Protocatechuic acid improved growth performance, meat quality, and intestinal health of Chinese yellow-feathered broilers

ABSTRACTThe aim of this study was to investigate the effect of protocatechuic acid (PCA) on the growth performance, meat quality, and intestinal health of Chinese yellow-feathered broilers. Growing broilers were fed the basal diet or diets supplemented with 300 or 600 mg/kg PCA, or 200 mg/kg enramycin for 52 D. We found that addition of 300 mg/kg PCA significantly increased body weight, live weight, and carcass weight and decreased the feed to gain ratio of broilers; PCA improved meat quality through reducing shear force, and increasing a* (relative redness) and decreasing b* (relative yellowness) at 24 h after slaughter. The activities of alkaline phosphatase and diamine oxidase in plasma were significantly decreased by administration of 300 mg/kg PCA; PCA also significantly increased total antioxidant capability and decreased malondialdehyde content and activity of xanthine oxidase in liver. Meanwhile, it enhanced activities of total superoxide dismutase, glutathione s-transferase, and glutathione peroxidase in the jejunal mucosa. Interleukin-10 and transforming growth factor-β were significantly increased in jejunal mucosa and plasma of 300 mg/kg PCA diet group, whereas interluekin-2 and interferon-γ dropped dramatically. Moreover, relative expression of apoptosis-related genes decreased in liver, whereas that of intestinal barrier-related and immunity-related genes increased in jejunum. Furthermore, 300 mg/kg PCA treatment significantly changed α-diversity and structure of the cecal microflora in broilers, with increasing relative abundance of Firmicutes and Actinobacteria while reducing Bacteroidetes and Proteobacteria. These results indicated that PCA improved the feed efficiency, growth performance, meat quality of broilers, and antioxidant capacity. It also enhanced intestinal immune function and improved the structure of intestinal flora to favor improved intestinal health in Chinese yellow-feathered broilers.

Investigation on physical change and storability of meatball after treated with different levels of liquid smoke and storage time

This present work investigated physical change and storability of buffalo meatball after treated with different levels of liquid smoke and storage time. Completely randomized design consisting of 2 factors (liquid smoke levels: 0, 1, 2%; storage time: 0, 1, 2, 3 weeks) was arranged, with 3 replications. Analysis of variance was employed to evaluate data, followed with LSD test. The results showed that liquid smoke could reduce shear force of meatball and TPC, but increase rancidity. Meanwhile, all parameters studied (shear force, TPC, and rancidity) tended to be lower along with storage time. In addition, both factors seemed to exhibit similar response oto shear force and TPC. In conclusion, the addition of liquid smoke 2% and storage time of 1 week resulted in the most desirable effect on buffalo meatball.

The effect of nuts and oilseeds enriching on the quality of restructured beef steaks

The objective of the study was to determine the effect of enrichment of restructured beef steaks with various types of nuts and oilseeds on their quality. According to our results, the addition of nuts and oilseeds affected the quality of the various features of the products. Among the studied nuts and oilseeds, flaxseeds showed the most adverse effect on the quality of the product. It caused, i.a.: significant (P < 0.05) increase in cooking loss (from control 12.2–14.9%), reduction of shear force (from control 91.5 to 35.6 N) and penetration force (from control 47,7–19.1 N), color change (increase L*, a*, b* parameters) and a reduction of scores granted for the product in sensory quality evaluation. Concurrently, the addition of these seeds allowed to a significant (P < 0.05) increase the content of n-3 PUFA in the product (from 0.49 control to 22.24%). The slightest changes were found in the texture and sensory quality of the products after the addition of pecan nuts, walnuts, peanuts, and pistachios. Among the nuts tested, the most nutritionally beneficial modification of lipid profile (increasing n-3 PUFA to 6.06%) was obtained by the addition of walnuts.

Experimental investigation of buckling-restrained steel plate shear walls with inclined-slots

A buckling-restrained steel plate shear wall with inclined slots (simply referred as “slotted SPSW”) consisting of an inner steel plate sandwiched between two precast concrete panels, has been developed as an energy dissipation device of structures. The steel strips between inclined slots behave like a series of buckling-restrained braces to dissipate the energy through inelastic axial deformation when subjected to cyclic loading. This paper experimentally investigated the seismic behavior of slotted SPSWs. Three half-scale specimens were fabricated and tested under quasi-static cyclic loading. Details for proper fabrication of slotted SPSWs were firstly configured. The results illustrated that the slotted SPSW could sustain the target lateral drift ratio (2%) without a reduction of shear force and energy dissipation capacity. Moreover, the tested specimens exhibited stable fatigue hysteresis loops when the cyclic loadings were repeated 30 times at 1.5% peak lateral drift ratio. The maximum drift ratio of tested specimens reached 3.5%, and the cumulative plastic ductility factor was larger than 200. The experimental results indicate that the slotted SPSW is capable of providing high lateral force-resisting and energy dissipation, which can be widely used in engineering structures.

Effect of an improved seat cover on back-support for reducing shear force applied to the buttocks when back-support is reclined

Effect of an improved seat cover on back-support for reducing shear force applied to the buttocks when back-support is reclined

Design Shear Force Reduction Factor of Upper Structure in Seismic Base-isolated System Considering Response Acceleration Decrement Effect

Design Shear Force Reduction Factor of Upper Structure in Seismic Base-isolated System Considering Response Acceleration Decrement Effect

Altered Neural Control Reduces Shear Forces and Ankle Impedance on a Slippery Surface.

This study investigated the consequences of reduced ankle muscle activity on slippery surfaces. We hypothesized that reduced activation would reduce shear forces and ankle impedance to improve contact and reduce slip potential. Data were collected from unimpaired adults walking across non-slippery and slippery walkways. Set within the walkway was a robotic platform with an embedded force plate for collecting shear forces and estimating the mechanical impedance of the ankle; impedance was characterized by a model with stiffness, damping, and inertia. We found a significant reduction in shear force due to reduced muscle activity in late mid-stance. We found no significant difference in stiffness between the surfaces. However, the muscle activation changes that contributed to shear force modulation occurred in late mid-stance, where reliable impedance estimates could not be made due to the foot leaving the measurement platform. When impedance could be measured, we found that a change in muscle activity predicted a change in stiffness, providing indirect estimates that stiffness was likely reduced later in stance. These results suggest that reduced muscle activity on slippery surfaces serves to reduce shear forces, and possibly also stiffness, during late mid-stance. These results have implications for identifying and training likely fallers, and possibly for designing prosthetic systems that help prevent falls when walking across different terrains.

The effect of combining tenderstretching and electrical stimulation on alpaca (Vicugna pacos) meat tenderness and eating quality

The effect of combining tenderstretching (TS; carcase suspension by the pelvic bone) with medium voltage electrical stimulation (ES) during processing on the tenderness of alpaca muscles was investigated. Thirty-six split alpaca carcases were randomly allocated to treatments in a 2 × 2 factorial arrangement (Achilles hung/TS and ES/non-ES). Samples were collected from the m. longissimus thoracis (LT), m. adductor femoris (AF), m. semimembranosus (SM), m. semitendinosus (ST) and m. psoas major (TL) at 24 h post slaughter for shear force, sarcomere length, collagen and myofibre (particle size) measurement. Additional samples were taken from the m. longissimus lumborum (LL) for sensory assessment using an untrained consumer panel. Tenderstretching reduced shear force and variability within the alpaca AF, without negatively affecting the TL, while ES significantly improved TL and LT tenderness. Consumers were able to detect ES treated LL, rating ES samples higher for all sensory traits. Combining ES and TS maximizes alpaca carcase tenderness when considered on a multiple muscle basis.

Influence of seismic isolation systems and soil-structure interaction on the response of structures

The reduction of cyclic loading triggering major damage in urban areas is a major challenge in earthquake engineering. The processes of structural control especially control structures for passive isolation systems and earthquake sinks of energy, which consists in superimposing on the structure a device which modifies the rigidity or the damping of the structural system without the demand for an external energy source and without introducing energy for its operation, these devices with taking account the effect of soilstructure interaction are currently regarded as effective solutions to these problem by reducing the level of acceleration imposed on the structure and consequently forces shear and the relative displacements in the superstructure. This reduction of shear forces and displacements will limit the structural damage.

Effects of Ultrasound Pretreatment and Ageing Processing on Quality and Tenderness of Pork Loin

Tenderness is a primary indicator of meat quality, which directly influences consumer acceptance of the meat. Ultrasound can effectively increase the tenderness of red meat, such as pork and beef, by breaking up muscle fibers and connective tissues through mechanical force, thus making it a basis for physical tenderization of meat to improve meat quality. In this study, ultrasound (2200 W, 15 kHz) was applied in the processing of pork loin to explore the influences of varying treatment durations (0-6 minutes) and posttreatment aging durations (0-2 days) on the tenderness, texture profile, physical and chemical qualities (myofibrillar fragmentation index, or MFI, and rate of marinade absorption), and sensory evaluation (9-point hedonic scale) of meat. The results indicated that ultrasonic treatment (2200 W) for 6 minutes can effectively tenderize the meat by increasing the MFI to 15.1%, lowering the hardness in texture profile analysis (TPA) to 87.6%, and reducing shear force to 87.9%. Moreover, if pork loin is allowed to age for 48 hours following 6 minutes of ultrasonic treatment, shear force can be further reduced to 72.3%. The sensory evaluation scores for texture, tenderness, and overall acceptance of pork loin increased with the elongated ultrasonic treatment.

Fluid viscous dampers locations in reinforced-concrete core wall buildings

Conventionally, a flexural plastic hinge is assigned and detailed at the core wall base and coupling beams ends to control seismic responses. This strategy is based on allowing damage to main structural components. To avoid damage to main structural components, an alternative strategy using energy dissipating devices, such as fluid viscous dampers (FVDs), is currently being studied and implemented. In this study, the effect of FVD locations on a 40-storey, high-rise, reinforced-concrete core wall case study building has been studied in detail using non-linear response history analysis for seven spectrally matched ground motions. FVDs were installed at strategic locations, identified based on maximum ‘design basis earthquake’ elastic modal racking shear deformation demands and force (shear and moment) demands in three different options. The force, deformation and energy demands on structural components are compared for conventional design and different options of FVDs. The comparison with conventional design shows that FVDs are effective not only for reducing shear force demand along wall height, bending moment demand at mid-height and deformation demands by 10, 45 and 35%, respectively, but also significantly reduce the rotation and energy demands in the core wall by 60 and 450%, respectively.

Effect of Wind on Multi Storey Buildings of Different Shapes

Objective of the Study: To study and analyse the effect of wind load on different shape of the building and asses the most structurally stable shape of a multi storey structure. Method: The present study deals with the buildings of seven different shapes: Rectangular; L; U; T; I; Plus and Non-uniform IS: 875 (Part 3)-1987 is the standard code of practice for design loads of buildings and structures which was used to calculate the gust factor. Further, all these shapes were analyzed using Staad. Pro 2007 software. Each building is a 50 storied building with storey height as 3m summing upto a total height of 150m.For, the purpose of analysis the plan area and stiffness of the columns were kept equal. Dead loads and Live loads were calculated by using the code IS: 875-1987 (Part 1, 2) respectively. By using the Indian standard codes the combinations of loads were taken. Parameters like Storey drift, Joint displacement, Intensity, Bending moment are used for the assessment.Based on this study it can be established that the shape of structure plays a very important role in resisting wind loads Findings: Plus Shape and Non uniform shape were the most stable shapes whereas L-shape and U-shape was the least stable of all the shapes. More the stiffness of the building more will be its stability. Storey drift and joint displacement increases with increase in height. A reduction in Shear force and bending moment was detected with the increase of height. Application: With the increase in population and shortage of land, it has become necessary to construct high rise buildings. Wind load plays an important role in tall structures while designing buildings. Thus, to understand and analyse the wind effect on structures.

The combined effects of grain supplementation and tenderstretching on alpaca (Vicugna pacos) meat quality

This study investigated the effects of feeding a mixed grain supplement and tenderstretching (TS) alpaca carcasses on meat quality. A total of 56 castrated 24month old alpacas were divided into two treatments (pasture-only, and pasture plus supplementation). Supplemented groups were fed a mixed grain ration in addition to ad lib pasture for 10weeks. Animals were slaughtered across two kill days (n=28). One half of each carcass was suspended by the pelvis (TS) prior to chilling, and the other half was Achilles tendon hung (AH). After 24h, muscles were removed and aged for 10 and 25d. TS significantly increased sarcomere length and reduced shear force and cooking loss in the m. semimembranosus. This trend was not observed in other muscles including the m. longissimus thoracis et lumborum (LL) and m. psoas major. Ageing period resulted in a marginal improvement in LL tenderness. There is clear evidence that TS improves tenderness in the hindquarter of alpacas.

Differences between sexes, muscles and aging times on the quality of meat from Wagyu × Angus cattle finished in feedlot

Our objectives were to assess quality parameters and chemical composition, and to evaluate the effects of sex, muscle and aging time on the quality of meats from Wagyu × Angus cross cattle reared under tropical conditions. Analyses were performed on the longissimus thoracis, semitendinosus and triceps brachii muscles obtained from chilled carcasses of a total of 30, 24-month-old, male (immunocastrated) and female animals (15 each sex). An effect of sex (P ≤ 0.05) was observed for subcutaneous fat thickness, marbling score, and ribeye area. The longissimus thoracis muscle from males was less (P &lt; 0.0001) marbled than that from females, but males had greater subcutaneous fat thickness (P = 0.0001) and greater ribeye area (P = 0.0411) compared with females. No effect of sex (P ≥ 0.05) was observed for fat colour measures. An interaction effect of sex and muscle (P &lt; 0.03) was detected for cooking loss, yellow intensity (b*), ash, and fat. Main effect of sex was not observed (P &gt; 0.07) only for the ultimate pH and water-holding capacity. Greater shear force and moisture values were observed (P &lt; 0.01) in meat from males than that from females, but a greater value of luminance (L*), red intensity (a*), chroma (C), hue (Ho), dry matter and protein was observed (P &lt; 0.001) in meat from females than that from males. Main effect of muscle was not observed only for water-holding capacity (P = 0.13). Ultimate pH and shear force values were lesser (P &lt; 0.001) in the longissimus thoracis muscle compared with other muscles. The triceps brachii muscle had the least (P ≤ 0.001) L* and Ho values among muscles, whereas the semitendinosus muscle had the greatest values of a* and C (P &lt; 0.001). The semitendinosus muscle presented the greatest (P &lt; 0.01) protein content compared with other muscles, although not differing in moisture and dry matter content from the triceps brachii muscle. An interaction effect of sex × aging time was observed for ultimate pH (P = 0.0110), meat colour parameters (except for Ho; P ≤ 0.01), and fat L* (P = 0.0025). Greater cooking loss, shear force, and fat a* values were observed (P &lt; 0.01) in meat from males than that from females, but greater values of meat Ho, fat a* and Ho, dry matter, and protein were observed (P ≤ 0.03) in meat from females than that from males. Meat aging of longissimus thoracis reduced shear force. Based on these findings, we recommend that meat from Wagyu × Angus cross cattle should be aged during 7 days because, although differences between 7 and 14 days were observed in either aging times, meat subjected to this process is considered as very tender, based on shear force values. In addition, aging in a shorter period of time can reflect on costs by reducing particularly those related with energy, due to less refrigeration time.

Myofibrillar Protein, Lipid and Myoglobin Oxidation, Antioxidant Profile, Physicochemical and Sensory Properties ofCaprine longissimus thoracisduringPostmortemConditioning

The study examined the impact of refrigerated storage on antioxidant profile, oxidative changes in myoglobin, lipids and myofibrillar proteins and quality attributes of longissimus thoracis (LT) muscle from goats. Analyses were conducted on LT obtained from carcasses of sixteen Boer bucks on 0, 1, 5 and 10 days postmortem. Ageing had no effect on antioxidant enzyme activities. Concentration of tocopherols and total carotenoids decreased over storage. Myoglobin, metmyoglobin reducing activity, redness and shear force decreased while metmyoglobin content and drip loss increased over storage. Free thiol decreased while carbonyls and TBARS increased over storage. The relative density of myosin heavy chain, actin and troponin T and the concentration of n−6 and n−3 fatty acids were stable until day 5 but declined afterward. Tocopherol and carotenoid were correlated (P < 0.05) with oxidative changes. Ageing did not affect consumer preference for juiciness, flavor and overall acceptability. However, preference for tenderness increased over storage. Practical Applications Information on the impact of postmortem ageing on the antioxidant status of chevon in relation to its oxidative changes, physicochemical properties and shelf life is limited. This study demonstrates that although tenderness improved, quality loss during ageing of chevon is inexorable. The tocopherols and carotenoids are the primary drivers of postmortem oxidative stability of chevon. Antioxidant enzymes do not seem to play a significant role in the postmortem oxidative stability of chevon. The oxidative stability of longissimus thoracis in goats could be maintained for 5 days during chill storage. The current findings would provide useful information to consumers, retailers and meat industries on the merits and demerits of postmortem ageing of chevon and the factors to consider when longer ageing periods are desired or necessitated.

Optimization the Resistance Spot Welding Parameters of Austenitic Stainless Steel and Aluminum Alloy Using Design of Experiment Method

This research aims to study the effect of RSW parameters on the sheerforce of the spot weldedfor two materials {AISI 304L and AA 6061-T6}with (0.5 and 0.7 mm) thickness. Three values for each welding parameters (welding current, electrode force, squeeze time and welding time) are to be used. The effect of those parameters has been analyzed by using design of experiments (DOE) in order to determine and reduce the number of the tested specimens. The experimental tests have been donethat are;shear, micro hardness tests and microstructure examination. It was found that the maximum shear force in welding of similar material AISI 304L is (F = 4.78 KN for t = 0.7 mm), while in the joint of dissimilar material (AA 6061-T6 with AISI 304L), the maximum shear force is (F = 1.42 KN for t = 0.7 mm). These values have been optimized to reach (F =5.13 KN & F =1.54 KN) respectively by using DOE. The minimum shear force was (F = 0.07 KN in t = 0.5 mm). It was found that, increasing the welding current and sheet thickness gave an increase in the shear force, but at the same time the reduction in shear force has occurred during the increasing in electrode force, squeeze time and welding time. From micro hardness tests, it was found that the maximum value of hardness was at the center of nugget zone (NZ) and it reduces slightly until reaching constant values away from nugget zone.

Comparison of myofibrillar protein degradation, antioxidant profile, fatty acids, metmyoglobin reducing activity, physicochemical properties and sensory attributes of gluteus medius and infraspinatus muscles in goats

BackgroundThe functionality of myofibrillar proteins is a major factor influencing the quality attributes of muscle foods. Nonetheless, the relationships between muscle type and oxidative changes in chevon during ageing are meagrely elucidated. Postmortem changes in antioxidant status and physicochemical properties of glycolytic gluteus medius (GM) and oxidative infraspinatus (IS) muscles in goats were compared.MethodsTwenty Boer bucks (9–10 months old, body weight of 36.9 ± 0.725 kg) were slaughtered and the carcasses were subjected to chill storage (4 ± 0.5 °C). Analyses were conducted on GM and IS muscles sampled on 0, 1, 4 and 7 d postmortem.ResultsChill storage did not affect the antioxidant enzyme activities in both muscles. The IS had greater (P < 0.05) superoxide dismutase and catalase activities than GM. Carotenoid and tocopherol contents did not differ between muscles but decreased (P < 0.05) over storage. The IS had higher (P < 0.05) glycogen and ultimate pH and lower (P < 0.05) shear force and cooking loss than GM. The carbonyl content, % metmyoglobin, drip loss and TBARS increased (P < 0.05) while free thiol, metmyoglobin reducing activity (MRA), shear force and myoglobin decreased (P < 0.05) over storage. Muscle type had no effect (P > 0.05) on free thiol, MRA and TBARS. The GM had lower (P < 0.05) redness on d 0 and 1 than IS while the IS had greater carbonyl, % metmyoglobin and drip loss than GM on d 7. The reflective density of slow myosin heavy chain (MHC) was higher (P < 0.05) while the density of fast MHC and actin was lower (P < 0.05) in IS than GM. Regardless of muscle type, the density of MHC decreased (P < 0.05) while that of actin was stable over storage. Nonetheless, the degradation of fast and slow MHC was greater (P < 0.05) in IS than GM. Muscle type had no effect (P > 0.05) on consumer preference for flavour, juiciness and overall acceptability. However, IS had higher (P < 0.05) tenderness score than GM on d 1 and 4 postmortem. Intramuscular fat was higher (P < 0.05) in IS compared with GM. Fatty acid composition did not differ between the muscles. However, GM had lower (P < 0.05) n-6/n-3 ratio than IS. The n-3 and n-6 PUFA declined (P < 0.05) while the SFA increased (P < 0.05) over storage.ConclusionThe changes in myofibrillar proteins and physicochemical properties of goat meat during postmortem chill storage are muscle-dependent.