Empowering faculty to initiate STEM education transformation: Efficacy of a systems thinking approach.

Just a decade ago Vision and Change in Undergraduate Biology Education: A Call to Action was released, catalyzing several initiatives to transform undergraduate life sciences education. Among these was the Partnership for Undergraduate Life Sciences Education (PULSE), a national organization commissioned to increase the adoption of Vision and Change recommendations within academic life sciences departments. PULSE activities have been designed based on the recognition that life sciences departments and faculty are embedded within institutions of higher education which, similar to other large organizations, are complex systems composed of multiple, interconnected subsystems. The organizational change research suggests that effecting large-scale changes (e.g., undergraduate STEM education transformation) may be facilitated by applying systems thinking to change efforts. In this paper we introduce the approach of systems thinking as a professional development tool to empower individual STEM faculty to effect department-level transformation. We briefly describe a professional development experience designed to increase life sciences faculty members' understanding of systems thinking, present evidence that faculty applied a systems thinking approach to initiate department-level change, and discuss the degree to which transformation efforts were perceived to be successful. Though focused on faculty in the life sciences, our findings are broadly transferable to other efforts seeking to effect change in undergraduate STEM education.

A Two-test Protocol for the Precise Determination of the Maximal Lactate Steady State.

The purpose of this study was to determine the efficacy of a two-test method for precisely identifying the Maximal Lactate Steady State (MLSS). Eight male competitive cyclists performed two bouts on a cycle ergometer. Following a maximal oxygen consumption (V̇O2max) test (66.91 ± 5.29 mL·kg-1·min-1) we identified the lactate deflection point using the visual deflection (TVis), Log-Log (TLog), Dmax (TDmax), RER = 1.00 (TRER), ventilatory threshold (TVent), and the 1.0 mmol·L-1 increase above baseline (T+1) methods. The second incremental test (SIT) consisted of 6-7 stages (5 min each) starting 20-30 W below to 20-30 W above the predetermined deflection point, in 10 W increments. Comparison of the two tests yielded different threshold estimates (range 11-46W) for all methods (P = 0.001-0.019) except the TLog (P = 0.194) and TRER (P = 0.100). The SIT resulted in significantly (P = 0.007) more narrow range of thresholds (27.5 ± 11.01W) compared to the V̇O2max test (70 ± 42.51W). The TVis from the SIT was identified as the MLSS and was verified using three 45-minute steady-state exercise bouts at 95%, 100%, and 105% of MLSS intensity (average increment 12.8 W). Blood lactate and V̇O2 were recorded every 5 minutes and differed between the three intensities at every time point (P < 0.001). V̇O2 increased from the 5th to the 45th minute by 7.02 mL·kg-1·min-1 (100% MLSS), 3.63 mL·kg-1·min-1 (95% MLSS) and 7.5 mL·kg-1·min-1 (105% MLSS, to the 30th minute). These results indicate that the MLSS was identified correctly by the SIT, the single incremental test overestimated the MLSS intensity, and the TVis provides a very accurate determination of the lactate breakpoint. The use of a second submaximal test is required for a precise identification of MLSS.

In-Season High-Intensity Interval Training Improves Conditioning In High School Soccer Players.

Soccer is characterized by high aerobic demands interspersed with frequent bursts of anaerobic activity. High-intensity interval training (HIIT) is considered a viable alternative to traditional endurance conditioning and offers the additional time-saving benefits of anaerobic training. We hypothesized that HIIT will compare favorably to traditional (aerobic-based) soccer conditioning over the course of a high school soccer season. Junior varsity soccer players were split into control (CON, n=16) and experimental (HIIT, n=16) groups for the 10-week study. The HIIT group performed 4-6 "all-out" sprints lasting 30s each, with 4.5 minute recovery, 3 times a week. The CON group performed endurance running for the same duration. The groups did not differ in any other aspect of their training. Participants completed the Yo-Yo intermittent recovery test level 1 (IR1), a 40-yard dash, vertical jump, Illinois agility test, and a sit-and-reach test, in two different testing sessions (pre/post season). Both HIIT and CON groups exhibited significant increase in IR1 test performance with time (741.6±307.6m vs. 1067.6±356.8m, p<.001 and 733.2±318.8m vs. 1165.2±252.8m, p<0.001 respectively), with no difference between groups. The CON group demonstrated a significant difference in the 40-yard dash over time (5.48±0.36s vs. 5.21±0.16s, p<0.004). While there was a difference in vertical jump between the pre and post tests for the HIIT group (42.20±7.04cm vs. 47.87±750cm respectively, p<0.019), no such effect was observed in the CON group. In contrast, there were differences in the agility test only for the CON group over time (16.67±0.76s vs. 16.15±0.49s, p<0.001). There were no differences in the flexibility test between groups. Our results indicate that HIIT offers similar endurance improvements to more traditional soccer training.

Similar metabolic response to lower- versus upper-body interval exercise or endurance exercise.

PURPOSE: To compare energy use and substrate partitioning arising from repeated lower- versus upper-body sprints, or endurance exercise, across a 24-h period. METHODS: Twelve untrained males (24±4 y) completed three trials in randomized order: (1) repeated sprints (five 30-s Wingate, 4.5-min recovery) on a cycle ergometer (SITLegs); (2) 50-min continuous cycling at 65% V̇O2max (END); (3) repeated sprints on an arm-crank ergometer (SITArms). Respiratory gas exchange was assessed before and during exercise, and at eight points across 22h of recovery. RESULTS: Metabolic rate was elevated to greater extent in the first 8h after SITLegs than SITArms (by 0.8±1.1kJ/min, p=0.03), and tended to be greater than END (by 0.7±1.3kJ/min, p=0.08). Total 24-h energy use (exercise+recovery) was equivalent between SITLegs and END (p = 0.55), and SITLegs and SITArms (p=0.13), but 24-h fat use was higher with SITLegs than END (by 26±38g, p=0.04) and SITArms (by 27±43g, p=0.05), whereas carbohydrate use was higher with SITArms than SITLegs (by 32±51g, p=0.05). Plasma volume-corrected post-exercise and fasting glucose and lipid concentrations were unchanged. CONCLUSION: Despite much lower energy use during five sprints than 50-min continuous exercise, 24-h energy use was not reliably different. However, (i) fat metabolism was greater after sprints, and (ii) carbohydrate metabolism was greater in the hours after sprints with arms than legs, while 24-h energy usage was comparable. Thus, sprints using arms or legs may be an important adjunct exercise mode for metabolic health.

Low-Volume Intense Exercise Elicits Post-exercise Hypotension and Subsequent Hypervolemia, Irrespective of Which Limbs Are Exercised.

INTRODUCTION: Exercise reduces arterial and central venous blood pressures during recovery, which contributes to its valuable anti-hypertensive effects and to facilitating hypervolemia. Repeated sprint exercise potently improves metabolic function, but its cardiovascular effects (esp. hematological) are less well-characterized, as are effects of exercising upper versus lower limbs. The purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) sprint intervals versus endurance exercise, and (ii) sprint intervals using arms versus legs. METHODS: Twelve untrained males completed three cycling exercise trials; 50-min endurance (legs), and 5(*)30-s intervals using legs or arms, in randomized and counterbalanced sequence, at a standardized time of day with at least 8 days between trials. Arterial pressure, hemoglobin concentration and hematocrit were measured before, during and across 22 h after exercise, the first 3 h of which were seated rest. RESULTS: The post-exercise hypotensive response was larger after leg intervals than endurance (AUC: 7540 ± 3853 vs. 3897 ± 2757 mm Hg·min, p = 0.049, 95% CI: 20 to 6764), whereas exercising different limbs elicited similar hypotension (arms: 6420 ± 3947 mm Hg·min, p = 0.48, CI: -1261 to 3896). In contrast, arterial pressure at 22 h was reduced after endurance but not after leg intervals (-8 ± 8 vs. 0 ± 7 mm Hg, p = 0.04, CI: 7 ± 7) or reliably after arm intervals (-4 ± 8 mm Hg, p = 0.18 vs. leg intervals). Regardless, plasma volume expansion at 22 h was similar between leg intervals and endurance (both +5 ± 5%; CI: -5 to 5%) and between leg and arm intervals (arms: +5 ± 7%, CI: -8 to 5%). CONCLUSIONS: These results emphasize the relative importance of central and/or systemic factors in post-exercise hypotension, and indicate that markedly diverse exercise profiles can induce substantive hypotension and subsequent hypervolemia. At least for endurance exercise, this hypervolemia may not depend on the volume of post-exercise hypotension. Finally, endurance exercise led to reduced blood pressure the following day, but sprint interval exercise did not.

Challenging the Accuracy of a Single-test Lactate Threshold Protocol in Collegiate Rowers.

Elite rowers use lactate threshold (LT) estimates as a basis for training intensity in order to achieve the greatest training volume. For convenience, LT is usually determined in a maximal LT/VO2max test. This simultaneous test is problematic because it requires a large power increment, which may not give the most accurate LT. PURPOSE: To challenge the validity of a simultaneous LT/VO2max test to estimate LT in rowers. METHODS: Collegiate rowers (n=20, 16F and 4M, age 19.3±1.3 years, height 171.5±7.1 cm, weight 70±14 kg, VO2max 44.6±5.5 ml•kg-1•min-1) performed two LT tests. Participants completed an incremental VO2max test with 3-minute intervals increasing by 30W and 40W for women and men respectively. The second test consisted of five 6-minute stages of 10W increments starting from 20W below the estimated LT. For both tests, blood lactate was measured at the end of each stage and LT was determined by the lactate deflection point. The difference in intensity between the first deflection point and the LT was then calculated. RESULTS: Average difference between LT1 and LT2 was 1.15 ± 13.4W, and were not statistically different (p=0.204). Average absolute difference was 9.95 ± 8.80W, and was different from the average (p=0.022). CONCLUSION: A second incremental test should be performed for the most precise determination of LT. This is particularly important to rowers who rely on LT to determine training intensities.

Studying reliability using identical handheld lactate analyzers.

Accusport analyzers were used to generate lactate performance curves in an investigative laboratory activity emphasizing the importance of reliable instrumentation. Both the calibration and testing phases of the exercise provided students with a hands-on opportunity to use laboratory-grade instrumentation while allowing for meaningful connections to be made between data collection and analysis. Pairs of student teams tested individual aerobically trained participants exercising to voluntary exhaustion on a cycle ergometer. The analysis of four volunteers' postexercise blood samples revealed lactate data that, although highly correlated, showed small but statistically significant differences between devices. This laboratory activity provides a useful platform for introducing students to the reliability of instrumentation, in particular noting its relevance to designs employing repeated measures.

Beyond the printed page: physiology education without a textbook?

Pedagogical innovations, ideas, and outcomes designed to enhance student learning in physiology courses are encouraged by our professional organizations and are actively discussed at conferences and in Advance in Physiological Education. Here, we report our experiment with freely available internet-based material as a substitute for the textbook for a single chapter on muscle physiology in a sophomore-level Human Physiology course. Student reactions to the textbookless curriculum were registered with the use of a questionnaire. Their responses indicated that they enjoyed the online material (animations, images, reviews, etc.), the emphasis on important concepts, and the variety of resources. Furthermore, students were almost unanimous in their praise for such pedagogical approaches to science education. Yet, students were reluctant to part with their textbooks. We believe that with subsequent iterations of this course we will be more successful at further separating the learning experience from the textbook. Reliance on freely available material may eventually relieve students from the burden of purchasing a costly textbook.

The external nasal dilator: style over function?

This study examined the effects of an external nasal dilator (END) on sedentary and aerobically trained women using the blood lactate threshold as a measure of aerobic performance. Three groups of women (sedentary, pre-season, in-season) participated in the study: nine sedentary college students (age 19 +/- 1.0 y), eight pre-season college athletes (age 20 +/- 2.3 y), and six in-season college rowers (age 20 +/- 1.7 y). A two-way repeated-measures design was used with subjects in each group being exposed to both conditions (with END and without END). The first two groups performed two incremental exercise tests in random order on a cycle ergometer, and the third group performed the tests on a rowing ergometer. Participants in each group wore an END strip for only one of the tests. Venous blood was collected at rest, during the final 30 seconds of each stage, and 1 and 3 minutes into the recovery period for the determination of blood lactate concentration and identification of the blood lactate threshold. No significant differences (P = 0.05) were found in blood lactate concentration at the lactate threshold between conditions for either group (sedentary: with END 2.51 +/- 1.18 mmol x L(-1), without END 2.56 +/- 0.84 mmol x L(-1); pre-season: with END 2.93 +/- 0.97 mmol x L(-1), without END 2.81 +/- 1.15 mmol x L(-1); and in-season: with END 3.93 +/- 0.50 mmol x L(-1), without END 3.49 +/- 0.387 mmol x L(-1)). We conclude that (a) the END did not improve the lactate threshold in either sedentary or trained college-age women, and (b) the END did not result in lower blood lactate levels during moderate to high-intensity exercise in the three groups examined in this study.

Adapting the learning-cycle to enrich undergraduate neuroscience education for all students.

A learning-cycle approach to science instruction is not new to science educators (Karplus, 1977; Kolb, 1984; Bergquist, 1991; Zollman, 1990; Allard and Barman, 1994). Somewhat less known, however, is the usefulness of this approach for creating lab activities for a broad audience of undergraduates. The following paper presents a brief overview of a laboratory activity that can be adapted for use by instructors of introductory neuroscience courses. The three-hour activity is geared towards tapping key elements of the learning-cycle approach, with a particular emphasis on the exploration phase of the model. Students work as members of small teams to explore a contemporary issue involving memory and gain hands-on experience from the outset, to which conceptual information is then added during lecture the following week. The approach is in marked contrast to the more traditional practice in the sciences where laboratory activities generally serve to punctuate already presented lecture material.

Prolonged exercise potentiates sarcoplasmic reticulum Ca2+ uptake in rat diaphragm.

The effects of a single bout of prolonged treadmill exercise [mean=81 (13) min] on sarcoplasmic reticulum (SR) Ca(2+) release, uptake and ATPase activity were determined in the costal region of rat diaphragm (D) and red gastrocnemius (RG). Glycogen depletion measurements made immediately following exercise suggested that treadmill running substantially recruited the fibers throughout both muscles. SR Ca(2+) ATPase activity, measured in isolated SR vesicles, decreased in the RG by 33% but remained unchanged in D in response to the exercise bout. This effect in RG was matched by a 37% decline in Ca(2+) uptake and a 28% depression in Ca(2+) release when measured in muscle homogenates. Conversely, Ca(2+) uptake increased between 157% and 263% in the D in the absence of any change in Ca(2+) release. These data show that the attenuation of SR function that has been consistently observed in limb muscle over the last several decades is absent in diaphragm despite the fact that its fibers appear to experience sufficient activity to deplete their glycogen. In fact, the large increase in Ca(2+) uptake in D shows that prolonged activity actually potentiates the ability of SR vesicles to sequester Ca(2+) in the absence of any increase in energy cost. Thus, it appears necessary to re-evaluate the role of exercise in regulating Ca(2+) sequestration by the SR as different muscles may respond in ways that are dictated by their function.