C-Reactive Protein Changes Following Treadmill and Cycling High-Intensity Interval Training

ABSTRACT: The acute inflammatory response to exercise has been well-studied in long duration activities such as marathons and triathlons; however, little work has been done investigating this response in high-intensity interval training (HIIT), which is characterized by intermittent bouts of higher and lower intensity cycles. PURPOSE: The purpose of this study was to investigate the changes in C-reactive protein (CRP) immediately following and 1-hour post HIIT protocols using two different exercise modalities, treadmill running and stationary cycling. METHODS: Eight young, healthy, recreationally active volunteers (1 female, 7 males; 25.50 ± 3.25 years) completed a 4x4 HIIT protocol (4-minute 85-95% HRmax active; 3-minute 60-70% HRmax recovery) on both a treadmill (TM) and a stationary cycle (CE). All participants completed both modalities in a randomized order 1 week apart. Blood samples were collected using Tasso+ devices attached to the upper arm. Plasma was isolated and frozen at -80C until protein analysis. CRP was measured using CRP ELISA kits (Millipore CYT298). Data are presented as percent change, pre- and post-HIIT bouts. RESULTS: CRP concentration did not change (-0.06%) immediately following TM HIIT, however, it increased by 7.88% immediately following CE HIIT. After 1 hour of recovery, CRP decreased by -5.40% following TM HIIT and -6.16% following CE HIIT. CONCLUSION: The results of this study illustrate the different inflammatory profile changes immediately following HIIT exercise between a higher-impact exercise (TM) and a lower-impact exercise (CE). However, both modalities showed a similar decrease in CRP after 1 hour of recovery in relation to baseline values. This information can be useful when creating exercise interventions for populations that have altered inflammatory profiles. Future work should investigate the effects of other HIIT modalities (e.g., rowing) and protocols (e.g., 10x1) on the inflammatory and metabolic responses to exercise

A Survey of Internal Medicine Residents Comparing Virtual Academic Half Day to Traditional Academic Half Day Model

Introduction. Resident educational activities vary from institute to institute, with daily noon conferences or weekly academic half-day (AHD) models where dedicated protected time is available for resident teaching. The COVID-19 pandemic limited in-person educational activities, forcing residency programs to move toward virtual options, including the academic half-day (AHD). This survey-based cohort study aimed to understand residents\u27 perception of virtual versus in-person AHD for educational activities during residency. Methods. The survey was emailed to 72 Internal Medicine residency program residents at our institute during the first week of March, 2022. The responses were analyzed using descriptive statistics, Pearson\u27s chi-square test, and Fisher\u27s exact test. Results. Sixty-one residents responded to the survey and 59 were included in the analysis. Of the residents, 47.5 % (n = 28) were satisfied with their virtual learning experience, 23.7% (n=14) felt that it could be better, and 28.8% (n=17) were neutral about the virtual AHD experience. The 2nd and 3rd-year residents preferred a virtual model despite being earlier, indicating that an in-person AHD had more advantages than a virtual one. While 40.4% of all residents preferred AHD to be in person, 31.6% wanted it to be virtual, and 28.1% preferred a hybrid model. Conclusions. Virtual AHD using Zoom is a satisfactory alternative to in-patient AHD if the quality of talks can be improved. Residents performing clinical work during virtual A HD are challenging, and innovative solutions should be identified to prevent this from occurring

Lower Extremity Loading and Subsequent Muscle Soreness Following High-Intensity Interval Training Protocols: A Pilot Study

High-intensity interval training (HIIT) is a popular form of exercise that is being performed by the general population as well as athletes. There is little work into how the lower extremity loading within HIIT protocols differs among various exercise modalities and the effects these differences may have on resulting muscle soreness. PURPOSE: The purpose of this pilot study was to characterize lower extremity vertical reaction forces (vRF) during treadmill running and cycling HIIT protocols in young, healthy adults and to explore the relations of the vRF with delayed onset muscle soreness (DOMS). METHODS: Participants completed a heart rate maximum (HRmax) test and two 4x4 HIIT protocols with four 4-minute cycles of 85-95% HRmax active periods followed by 3-minute 50-60% HRmax recovery periods. vRF’s were measured using Moticon shoe insoles and normalized to body weight. The peak vRFs during the middle minute of each active period were averaged, then the 4 average active period values were averaged for a total average vRF for the HIIT protocol. DOMS was measured using a subjective, 10-point visual analog scale (VAS). Results are presented as mean ± SD. The relations between vRF and DOMS at 24h post-exercise was assessed using Pearson’s r. RESULTS: Peak vRF were significantly greater during running (2.25 ± 0.27 [BW]) compared to cycling (0.38 ± 0.09 [BW]) during the HIIT protocols. There was a strong correlation between running vRF and DOMS (r = 0.98); however, only a weak relation between vRF and DOMS in cycling (r = 0.21). CONCLUSION: These findings demonstrate large differences in lower extremity loading between running and cycling HIIT protocols and a strong association between running vRF and subsequent muscle soreness at 24h post-exercise. Recreational exercisers as well as athletes should be aware of how different exercise modalities influence muscle soreness following HIIT training to promote adherence and optimal performance

Inflammatory Response Following High-Intensity Interval Training (HIIT) Across Different Exercise Modalities: A Pilot Study

Exercise-related muscular contractions produce and release numerous myokines, namely interleukins (IL) 6, 8, and 10. Most studies have focused on longer duration (\u3e60 minutes) exercise and suggest that the IL-6 response to running is greater than that of cycling. However, to date, the effect of 4x4 High-Intensity Interval Training (HIIT) and modality on the inflammatory response to exercise have not been reported. PURPOSE: This pilot investigation characterized the inflammatory biomarker response to HIIT 4x4 running and cycling protocols. METHODS: Five young, recreationally active volunteers (1 female, 4 males; 27.20 ± 3.42 years) completed a heart rate max (HRmax) test monitored with a Polar HR chest strap. This was followed by randomized completion of a 4x4 HIIT protocol (4-minute 85-95% HRmax active; 3-minute 60-70% HRmax recovery) on a treadmill and a stationary bike. A licensed phlebotomist collected blood before and after exercise. Samples were centrifuged at 3000 RPM for 10 minutes before plasma was aliquoted and frozen at -80°C. Circulating levels of IL-6/8/10 from baseline and post-exercise were analyzed using a multiplexed Luminex system. Data are presented as fold changes ((post-baseline)/baseline), and are shown as mean ± SD. RESULTS: All inflammatory myokines had a positive fold change following the cycling protocol (IL-6: ∆=0.57 ± 1.30; IL-10: ∆ = 0.15 ± 0.36; IL-8: ∆ = 0.16 ± 0.29). Only IL-6 and IL-10 had positive fold changes following the running exercise (∆ = 0.07 ± 0.12; ∆ = 0.05 ± 0.08, respectively), while IL-8 had a negative fold change (∆ = -0.01 ± 0.17). CONCLUSION: The results of this pilot study suggest that the IL-6 driven inflammatory response to HIIT exercise may be higher in cycling compared to running. This finding may be important when prescribing exercise interventions for clinical populations. The shorter duration of HIIT exercise, coupled with the lower impact associated with cycling may prove beneficial for those less trained. This response to HIIT differs from previous studies in long-duration exercise that have shown increased responses to running versus cycling. Therefore, further research should continue to investigate inflammatory responses to HIIT in order to inform exercise prescription for various populations

Dietary Magnesium Intake on Heart Rate and Time-to-Fatigue During HIIT Exercise: A Pilot Study

In high intensity interval training (HIIT), bouts of intense work are alternated with less intense periods. HIIT provides an effective stimulus to increase the volume of exercise at or above 90% heart rate maximum (HRmax). Magnesium (Mg) modulates energy metabolism and enzymatic processes. Studies suggest that Mg assists oxidative transport, improves glucose availability, delays lactate accumulation, and reduces inflammation. A gap exists in understanding how Mg affects HIIT. Moreover, the influence of a Vegan (VD) vs Omnivore (OD) diet on HIIT performance outcomes (e.g., heart rate [HR] and time-to-fatigue [TTF]), has yet to be investigated. PURPOSE: This study explored the relations between VD and OD Mg intake and HRmax and TTF during a HIIT treadmill (TM) protocol. It was hypothesized that a higher Mg intake would be associated with a lower HRmax and extended TTF. METHODS: Five healthy participants (1 female, 4 males; 27.2 ± 3.4 years) were enrolled and completed a TM HRmax test and HIIT protocol. The HIIT session comprised four repetitions of 4-minute higher intensity bouts at 85-95% HRmax followed by 3-minute recovery periods at 60-70% HRmax. Dietary Mg was assessed using the ASA24 recall. Values are reported as group mean difference ± SD. Hedges g effect sizes (ES) were calculated, and Pearson correlation coefficients were determined. RESULTS: As expected, Mg intake was higher in VD than OD subjects with a large effect size (558.6 ± 29.0 mg, ES = 19.2). Differences in measured HRmax and TTF between groups was also observed, with VD having a lower HRmax (14.3 ± 1.5 bpm, ES = 9.3) and extended TTF (2.0 ± 0.5 min, ES = 3.9). A strong negative correlation (r = -0.98) was identified between Mg intake and measured HRmax, as well as Mg and RHR (r = -0.73). A moderate positive correlation (r = 0.66) was found for Mg intake and TTF. CONCLUSION: These preliminary data suggest that the higher Mg intake found in persons with a VD is associated with a lower HRmax and extended TTF during HIIT, compared to persons with an OD

Failure Analysis of Sapphire Refractive Secondary Concentrators

Failure analysis was performed on two sapphire, refractive secondary concentrators (RSC) that failed during elevated temperature testing. Both concentrators failed from machining/handling damage on the lens face. The first concentrator, which failed during testing to 1300 C, exhibited a large r-plane twin extending from the lens through much of the cone. The second concentrator, which was an attempt to reduce temperature gradients and failed during testing to 649 C, exhibited a few small twins on the lens face. The twins were not located at the origin, but represent another mode of failure that needs to be considered in the design of sapphire components. In order to estimate the fracture stress from fractographic evidence, branching constants were measured on sapphire strength specimens. The fractographic analysis indicated radial tensile stresses of 44 to 65 MPa on the lens faces near the origins. Finite element analysis indicated similar stresses for the first RSC, but lower stresses for the second RSC. Better machining and handling might have prevented the fractures, however, temperature gradients and resultant thermal stresses need to be reduced to prevent twinning

How Do You Measure That Ceramic Property?

By using the dozens of consensus test standards and practices developed by the Advanced Ceramics Committee of ASTM, C-28, the measurement of mechanical, physical, thermal, and performance properties can be properly performed. The what, how, how not, and why are clearly illustrated for beginning as well as experienced testers. Using these standards will provide accurate, reliable, and complete data for rigorous comparisons with other test results. The C-28 Committee has involved academics, and producers, and users of ceramics to write and continually update more than 45 standards since the committee's inception in 1986

Cycling Versus Treadmill Potentiation Effects Following High-Intensity Interval Training

High-intensity interval training (HIIT) has emerged as a popular form of exercise, with intermittent bouts of higher and lower intensity cycles. Not well understood to date is the influence of HIIT exercise modality (e.g., cycling vs treadmill running) on measures of jump performance. A generally accepted metric for assessing performance and overall athleticism involves performing a countermovement jump (CMJ). Furthermore, heavy exercise has been shown to improve muscle performance using post-activation potentiation. Purpose: This study compared the effects of HIIT bouts of cycling vs treadmill running on CMJ concentric impulse, peak takeoff force, and jump height. Methods: Eleven young, active adults (5 females, 6 males, 27.20 ± 3.42 years) completed 30-minute 4x4 HIIT protocols on a treadmill and stationary bike with a 7-day interval between measures. Participants also performed CMJs before and after the exercise bouts using VALD force plates. Impulse was calculated during the first 100ms of the concentric portion of takeoff and peak takeoff force was normalized to body weight. Values are presented as percent change. Results: Average concentric impulse increased by 3.2% following the cycling protocol and 4.7% following the treadmill protocol. Peak net takeoff force increased by 5.98 & following the cycling protocol and 8.57% following the treadmill protocol. These changes led to no difference in jump height following the cycling protocol (0.80%); however, jump height increased by an average of 4.05% following the running protocol. Discussion: This study illustrates that both cycling and running HIIT protocols can increase certain CMJ variables such as impulse and takeoff force. However, the treadmill HIIT protocol demonstrated a larger magnitude of change compared to cycling. The larger increase in these variables following running may have accounted for the increase in jump height seen after running and not after cycling. Treadmill running HIIT may simulate the post-activation potentiation phenomenon seen after strength training due to its higher-impact loading compared to cycling. These results could be of interest to athletic populations, as the results may help athletes decrease their risk of injury and increase performance

Does Carrying Golf Equipment Unilaterally or Bilaterally Influence Spatiotemporal Gait Parameters?

Golf is a popular multimodal recreational physical activity and sport. Golf equipment transportation (GET) is a consistent demand in golf, with over 6 kilometers of walking distance and 10,000 steps accrued, on average, in an 18-hole round. Gait asymmetries, especially in step time and step length, are associated with decreased efficiency and increased metabolic cost. Thus, gait asymmetries in different GET methods may have implications for fatigue and golf performance. PURPOSE: To compare symmetry in gait spatiotemporal parameters of two GET methods with each other and unloaded walking over flat ground. We hypothesized that GET would result in asymmetric step length and step time, and that unilateral would be more asymmetric than bilateral. METHODS: 20 experienced, young adult golfers (11M/9F, Age: 26.4±4.5 yrs) participated in 3D motion capture of 3 GET walking tasks: 1) unloaded walking (UW), 2) unilateral single-strap carrying on the right shoulder (SS), and 3) bilateral double-strap carrying across both shoulders (DS); using an 11kg bag. In each condition, the mean of 9 total steps resulting from 3 successful walking trials was analyzed. Kinematic data were collected at 60Hz and filtered at 6Hz. Post-processing and statistical analysis were performed in Visual 3D and R. Symmetry was evaluated for step time and length using a symmetry index that calculates the ratio of kinematics between limbs. One-way ANOVA was performed to compare symmetry for step time and length across conditions. RESULTS: Step time (F = 1.163, P = 0.32) and step length (F = 1.895, P = 0.16) between-limb symmetry were not different across SS, DS, and UW. CONCLUSION: Despite carrying a load of 11kg in the SS and DS, symmetry in step length and step time was maintained, contrary to our hypothesis. Increases in lower limb joint moments may be required to account for the magnitude and position of the external load in SS and DS and to maintain symmetry in spatiotemporal gait parameters. Therefore, lower extremity joint and trunk biomechanics should be investigated in GET to better understand the mechanical demands required to maintain gait symmetry. Exploring the effects of different GET methods on uneven surfaces may be more ecologically important to understanding fatigue or golf performance due to GET method

Unilateral Load Carriage in Golf Increases Frontal Plane Moment Demand at the Knee

Golf equipment transportation (GET) is a regular task in the sport of golf, a popular activity with more than 66 million participants globally. Unilateral GET is commonly practiced by junior and collegiate golfers, and professional caddies, who incur large walking distances daily, especially during competition. Therefore, the influence of GET on knee mechanics during gait has important implications for performance and injury risks. Furthermore, frontal-plane lower extremity (LE) demands including knee abductor moment during activities may alter knee mechanics and contribute to pain and progression of osteoarthritis (OA). Purpose: To compare the frontal-plane knee moments of two different GET methods to each other and unloaded walking. Methods: 20 experienced young golfers (11M/9F, Age: 26.4±4.5yrs) participated in 3D motion capture of 3 walking tasks: 1) unloaded walking (UW), 2) unilateral carrying on the right shoulder (SS), and 3) carrying the golf bag across both shoulders (DS); using an 11kg bag. For each condition, one stride was taken from each of the 3 successful trials for analysis. Kinematic and Kinetic data were collected at 60Hz and 1000Hz, respectively, and filtered with a 6Hz lowpass filter. Frontal-plane kinematics and kinetics were calculated in Visual 3D. Post-processing and statistical analysis were done in R and MATLAB. One-way ANOVA was used to compare across conditions. Hedge’s g effect sizes (ES) were calculated. Results: The left knee demonstrated higher peak knee abductor moment (PKAM; SS: 0.63 ± 0.08; DS: 0.48 ± 0.09; UW: 0.44 ± 0.07 Nm/kg) during SS compared to DS (pConclusion: PKAM increased on the contralateral knee and decreased on the ipsilateral side during unilateral GET with large effects. Higher PKAM is associated with knee disorders including pain and OA, and could also contribute to localized fatigue. While decreased PKAM on the ipsilateral knee may seem beneficial, bone-on-bone forces could be altered and redistributed. Future studies should investigate moment impulse and bone-on-bone forces associated with GET