VO2max is directly limited by the diffusion capacity of the lungs, maximum cardiac output, the oxygen-carrying capacity of the blood and several characteristics of skeletal muscle (9). A combination of the percentage of VO2max that can be maintained below the lactate threshold together with running economy is probably the best indicator of performance (9). The aim of this study was to investigate the effects of EIMD of the hip and knee extensor muscles from eccentric squats on VO2max and time to voluntary exhaustion through repeated maximal treadmill tests immediately after and two, four and seven days after the muscle-damaging protocol. .
Eccentric muscle damage causes a more violent stretch of the cruciate ligaments than concentric muscle action. This local inflammatory response leads to pain and decreased range of motion of the affected muscles (Enoka, 1996). RPE values did not differ significantly from baseline at 48 hours or seven days after EIMD for each minute of the time trial.
Because of the many different procedures that can be used to perform a VO2max test, a set of criteria has been compiled to determine whether the test has elicited a true VO2max. While measuring the oxygen consumption of a subject running on an outdoor track at increasing speed, they noticed that oxygen consumption was similar to the ceiling that the subject could reach, regardless of work intensity. He found that the average blood lactate concentration of the subjects who showed a plateau in VO2 was 7.9 – 8.4 mMol/L.
If the upward ramp test was not validated, a second supramaximal verification test was performed after another ten-minute rest period at a treadmill speed of 115% of the maximum speed achieved by the upward ramp test. The test showed that 85% (34 out of 40 participants) of the upward ramp tests were confirmed by the first. Terminology in terms of maximal oxygen uptake has also been reviewed (Howley et al., 1995). the highest oxygen uptake achieved during a treadmill test of adequate intensity and duration that met its objective criteria.
At the end of the study, 49 of these tests (61%) met the criteria for a "true" VO2max. These factors include the oxygen-carrying capacity of the lungs, peak cardiac output, oxygen-carrying capacity of the blood, and several skeletal muscle characteristics (Bassett and Howley, 2000). The oxygen-carrying capacity, or more specifically the hemoglobin content, in the blood is the last of the central factors.
Greater angular excursion of the hips and shoulders around the polar axis in the transverse plane. Of these seven, knee extension, peak dorsiflexion time, and toe-off eversion velocity were found to account for 94.3% of improved running economy. While VO2max is primarily limited by central factors of the cardiovascular system (Bassett and Howley, 2000), the percentage of VO2max at lactate threshold is more limited by peripheral factors of skeletal muscle (Holloszy and Coyle, 1984).
The time period for the effects of EIMD is important because of the positive impact that resistance training, especially high-intensity resistance training using explosive movements or heavy weight, has on endurance running performance (Yamamoto, Lopez, Klau, Casa, Kraemer, and Maresh, 2008).
CHAPTER III METHODS
The researchers provided guidance on the use of perceived exertion scales and the assessment of leg muscle soreness. The breathalyzer included in the VO2max testing procedure was inserted into the participant's mouth, and a nose clip was placed over the participant's nose. The researcher provided instructions regarding the use of the perceived exertion and leg muscle soreness rating scale.
After this, the participant started running at a comfortable pace with the treadmill at 0% incline. When the participant signaled that they had reached exhaustion, the treadmill belt was slowed back down to 3.0 mph to allow the participant to cool down. For the second testing session, the participant reported to the Kevser Ermin Applied Physiology Laboratory approximately 48 hours after the first testing session.
This was done by having the participant slowly and controlled perform three separate body squats. After completing each body squat, the participant was asked to rate the intensity of pain/soreness in the quadriceps, gluteal muscles, and overall leg muscles, respectively, on a 10 cm visual analogue scale. The participant was instructed to place a mark along the 10 cm line corresponding to the intensity of pain experienced while squatting.
Next, the participant completed eccentric muscle actions (4 sets to failure with each leg) of the quadriceps and gluteus muscles performing split leg squats with a workload of 60% of their body weight. The participant was instructed to perform each eccentric muscle action in a slow (approximately 3 seconds) and controlled manner. The researchers assisted in lifting the weight before the start of each lift to ensure that the participant mainly
Participants were also reminded of the instructions for monitoring symptoms related to rhabdomyolysis and. Then, the participant rested for 20 minutes before muscle soreness in the same was reassessed. During the tests, a TrueOne 2400 Metabolic Measurement System (Sandy, UT) was used to analyze participants' breath.
Maximal Oxygen Consumption Following EIMD
Also, the improvement from 2 days post-‐EIMD to 7 days post-‐EIMD showed a trend approaching significance (p = 0.057).
Time to Exhaustion Following EIMD
In the present study, VO2max remained significantly lower than baseline for seven days post-‐EIMD, while time to exhaustion recovered to values comparable to baseline after two days of recovery. Because the protocol for the VO2max tests in the current study had standardized time intervals for increasing intensity, it is possible to make an indirect, general analysis of running economy following EIMD using the VO2max and time to exhaustion data. Chen, Nosaka, and Tu (2007) found that running economy was significantly reduced immediately after and for up to three days after a muscle-damaging protocol due to reduced force production capabilities, increased stride frequency, and reductions in stride length and range of motion in the knee and ankle joints.
The EIMD VO2max tests show that the VO2 measurement was highest immediately after the injury protocol and gradually decreased two, four and seven days after the injury. Higher VO2 values at comparable exercise times indicate the lowest economy immediately after the injury protocol, which gradually improves. Although statistical analysis of these figures was not performed, there are still indications of improved operating economics with recovery time.
Furthermore, lower VO2 levels accompanied by longer time to voluntary exhaustion after seven days of recovery technically indicate better running economy than at baseline times, which could mean that improvements in running economy can be seen with intense resistance training. in seven days. In addition, some participants completed their baseline VO2max test up to two weeks before returning for second testing due to university spring break. This could lead to a difference in the training status of the participants, leading to different results.
In conclusion, EIMD can potentially lead to a significant decrease in VO2max for up to seven days and a decrease in time to exhaustion at a given workload for up to . up to four days. If this is known to be true, it should be recommended that coaches/trainers include at least seven days of active recovery from resistance training before entering an athletic competition. Future research on this topic should attempt to control some specific aspects of the experimental design when using a similar protocol.
If this were possible, it would most . an appropriate time for the start of the study would be immediately after the competition season, allowing for as close to a realistic in-season training status as possible. Effect of exercise-induced muscle damage on respiratory and perceived exertion responses to moderate- and severe-intensity cycle exercise .. achievable VO2 during exercise in humans: the highest vs. the maximum problem. Effect of exercise-induced muscle damage on the blood lactate response of . stepwise training in humans.
