Modeling the behavior of anaerobic work capacity in cycling

Models of fatigue are based on physiological parameters such as Critical Power (CP) and Anaerobic Work Capacity (AWC). CP is a theoretical power that can be maintained indefinitely and AWC is a finite anaerobic energy reservoir for efforts above CP. There is an increasing interest in developing mathematical models of energy expenditure and recovery for athletic training and performance. Recently, researchers have developed formal mathematical models that aid in better management of performance. Most available models have originated from cycle ergometer tests due to the ease of measuring power in cycling. The objectives of this research are (i) to develop a testing protocol to understand expenditure and recovery of AWC in cycling, (ii) to establish AWC recovery profiles in terms of recovery powers and durations, and (iii) to combine AWC recovery with expenditure for energy management in cycling. Nine recreational cyclists performed a study which involved a VO2max ramp test to determine gas exchange threshold (GET), a 3-min all-out intensity test (3MT) to determine CP and AWC, and 9 intermittent cycling tests to understand recovery of AWC. Three cyclists completed all tests resulting in a complete profile of the AWC recovery. The results indicate that AWC recovered during recovery decreases with increasing recovery powers. No generic trends were observed in AWC recovery with respect to recovery durations. In addition, the tests indicate the need for individualized models owing to the inherent within-subject variability (WSV) associated with CP and AWC. Quantifying this WSV will aid in accurately modelling and optimizing performance

Impact of heavy metals on water, fish (Cyprinus carpio) and sediments from a water tank at Tumkur, India

This study was carried out to assess the concentrations of various heavy metals and their distribution in a hyper-eutrophic urban Tumkur tank system, which is being polluted from industrial, domestic and sewage effluents. Samples of water, fish and soil sediment were analyzed for the concentration of seven heavy metals (iron, zinc, copper, nickel, chromium, lead and cadmium) using atomic absorption spectrophotometry. The water-soluble (bioavailable) fractions of heavy metals correlated positively with their total concentration, exhibiting the following sequence of bioavailability: Zn > Cd > Ni > Pb > Cu > Cr > Fe. Cyprinus carpio exhibited a maximum bioaccumulation factor for copper (5500). The mean values of all types of collected samples were correlated with the corresponding mean values in a control tank (Teetha tank). The sequence of the order of the concentration of the metals in water, fish and sediment samples exhibiting higher values than those observed in the control tank was as follows: Cr > Pb > Cu ≈ Ni > Fe > Cd > Zn, Cr > Cd > Cu ≈ Zn > Pb > Fe ≈ Ni and Fe > Pb > Cr > Cu > Ni > Zn > Cd, respectively. The geoaccumulation indices of the heavy metals revealed that the tank is moderately to strongly contaminated. As Cyprinus carpio is extensively used for human consumption, there is a growing health risk that these metals could find their way into the human food chain

Unprecedented heavy landings of juvenile Kiddy shrimp, Parapenaeopsis stylifera along Karnataka coast

Parapenaeopsis stylifera is one of the most abundant and highly valued shrimp species in India. It forms about 20% of the penaeid shrimp catch of Karnataka with the period from January to June contributing the majority of the catch. In general, the post-monsoon months of August to December is considered as a lean period for P. stylifera. During this period single day fishing trawlers land catch of a mixture of fish, prawns, stomatopods and other crustaceans. The contribution of prawns in the catch is around 10 to 20%

An Experimental Protocol to Model Recovery of Anaerobic Work Capacity

Models of fatigue are based on physiological parameters such as Critical Power (CP) and Anaerobic Work Capacity (AWC). CP is a theoretical threshold value that a human can generate for an indefinite amount of time and AWC represents a finite expendable amount of anaerobic energy at intensities above CP. There is an increasing interest in developing mathematical models of energy expenditure and recovery for athletic training and human performance. The objective of this research is to propose and validate a model for recovery of AWC during a post exertion recovery interval of cycling. A cycling ergometer study is proposed which involves a VO2max ramp test to determine gas exchange threshold, a 3-min all-out intensity test to determine CP and AWC, and exertion-recovery interval tests to understand recovery of AWC. The results will be used to build a human in the loop control system to optimize cycling performance

A survey of mathematical models of human performance using power and energy

The ability to predict the systematic decrease of power during physical exertion gives valuable insights into health, performance, and injury. This review surveys the research of power-based models of fatigue and recovery within the area of human performance. Upon a thorough review of available literature, it is observed that the two-parameter critical power model is most popular due to its simplicity. This two-parameter model is a hyperbolic relationship between power and time with critical power as the power-asymptote and the curvature constant denoted by W′. Critical power (CP) is a theoretical power output that can be sustained indefinitely by an individual, and the curvature constant (W′) represents the amount of work that can be done above CP. Different methods and models have been validated to determine CP and W′, most of which are algebraic manipulations of the two-parameter model. The models yield different CP and W′ estimates for the same data depending on the regression fit and rounding off approximations. These estimates, at the subject level, have an inherent day-to-day variability called intra-individual variability (IIV) associated with them, which is not captured by any of the existing methods. This calls for a need for new methods to arrive at the IIV associated with CP and W′. Furthermore, existing models focus on the expenditure of W′ for efforts above CP and do not model its recovery in the sub-CP domain. Thus, there is a need for methods and models that account for (i) the IIV to measure the effectiveness of individual training prescriptions and (ii) the recovery of W′ to aid human performance optimization

Effect of Cissus quadrangularis Linn on skeletal growth in the neonates of diabetic rats

Background: Infants of the diabetic mother are known to have reduced bone mineral content and hypocalcemia. Earlier, it has been shown that petroleum ether extract of Cissus quadrangularis (PECQ) can enhance the fetal skeletal ossification in normal rats. The present study was designed to evaluate the effect of PECQ on skeletal growth in the neonatal rats of streptozotocin-induced diabetic rats.Methods: After confirmation of diabetes, the diabetic and non-diabetic female Wistar rats were kept for mating with healthy male rats. After positive vaginal smear test, the pregnant rats were divided into three groups; the normal (non-diabetic) control (NC), diabetic control (DC), and diabetic+CQ (D+CQ) groups. The rats in the D+CQ group were given PECQ (500 mg/kg B.Wt), whereas animals in NC and DC groups were given 0.5% carboxy methyl cellulose, throughout the gestational period. Femur from the 1 week old neonatal rats from each group was collected randomly and subjected to histological analysis.Results: Thickness of trabecular bone and periosteum was significantly reduced in the neonates of DC rats compared with the neonates of NC group. Pretreatment with PECQ significantly improved the thickness of trabecular bone and periosteum compared with neonatal rats of DC group. No significant differences were observed in the medullary cavity width of femur between the groups.Conclusion: Data from the present study suggest that the PECQ can effectively attenuate the diabetes-induced reduction in the early skeletal growth. However, further research is warranted to evaluate the exact mechanism of action of phytochemical constituents of PECQ that can cross the placental barrier

Modeling the Expenditure and Recovery of Anaerobic Work Capacity in Cycling

The objective of this research is to model the expenditure and recovery of Anaerobic Work Capacity (AWC) as related to Critical Power (CP) during cycling. CP is a theoretical value at which a human can operate indefinitely and AWC is the energy that can be expended above CP. There are several models to predict AWC-depletion, however, only a few to model AWC recovery. A cycling study was conducted with nine recreationally active subjects. CP and AWC were determined by a 3-min all-out test. The subjects performed interval tests at three recovery intervals (15 s, 30 s, or 60 s) and three recovery powers (0.50CP, 0.75CP, and CP). It was determined that the rate of expenditure exceeds recovery and the amount of AWC recovered is influenced more by recovery power level than recovery duration. Moreover, recovery rate varies by individual and thus, a robust mathematical model for expenditure and recovery of AWC is needed

Experimental Modeling of Cyclists Fatigue and Recovery Dynamics Enabling Optimal Pacing in a Time Trial

Improving a cyclist performance during a time-trial effort has been a challenge for sport scientists for several decades. There has been a lot of work on understanding the physiological concepts behind it. The concepts of Critical Power (CP) and Anaerobic Work Capacity (AWC) have been discussed often in recent cycling performance related articles. CP is a power that can be maintained by a cyclist for a long time; meaning pedaling at or below this limit, theoretically, can be continued for infinite amount of time. However, there is a limited source of energy for generating power above CP. This limited energy source is AWC. After burning energy from this tank, a cyclist can recover some by pedaling below CP. In this paper we utilize the concepts of CP and AWC to mathematically model muscle fatigue and recovery of a cyclist. Then, the models are used to formulate an optimal control problem for a time trial effort on a 10.3 km course located in Greenville SC. The course is simulated in a laboratory environment using a CompuTrainer. At the end, the optimal simulation results are compared to the performance of one subject on CompuTrainer.Comment: 6 pages, 8 figure

Sustainable utilization of discarded foundry sand and crushed brick masonry aggregate in the production of lightweight concrete

Nowadays, there is a considerable shortage in the availability of river sand and natural stone aggregate for the construction activities all around the globe and the way out is being worked out by the use of discarded foundry sand and crushed brick masonry aggregate for construction purposes. In the present study, river sand was partly replaced by the discarded foundry sand procured from steel moulding industries and the crushed brick masonry aggregate was used as coarse aggregate for the production of lightweight concrete. The experimental program involved casting of six distinct mixes with 0%, 20%, 40%, 60%, 80% & 100% replacement of fine aggregate by discarded foundry sand. The mechanical and durability properties of the lightweight concrete were assessed for each of the six diverse blends. Even though the 80% and 100% replacement mixes were found to be less dense than the rest of the mix, the blend of 40% replacement acquired desirable mechanical and durability properties when compared to that of all other mixes. The optimum replacement level of the discarded foundry sand by mass to the river sand was 40%. The lightweight concrete produced by utilizing crushed brick masonry aggregate and discarded foundry sand (40% substitution level) can be employed in all major structural lightweight construction aspects and is ideally suited for sloped roof slabs and making architectural or decorative concrete blocks