Effects of Sprint Interval Training With Active Recovery vs. Endurance Training on Aerobic and Anaerobic Power, Muscular Strength, and Sprint Ability.

Sökmen, B, Witchey, RL, Adams, GM, and Beam, WC. Effects of sprint interval training with active recovery vs. endurance training on aerobic and anaerobic power, muscular strength, and sprint ability. J Strength Cond Res 32(3): 624-631, 2018-This study compared sprint interval training with active recovery (SITAR) to moderate-intensity endurance training (ET) in aerobic and anaerobic power, muscular strength, and sprint time results. Forty-two recreationally active adults were randomly assigned to a SITAR or ET group. Both groups trained 3× per week for 10 weeks at 75% of V[Combining Dot Above]O2max for 30 minutes weeks 1-4, with duration increasing to 35 minutes weeks 5-7 and 40 minutes weeks 8-10. While ET ran on a 400-m track without rest for the full training session, SITAR sprinted until the 200-m mark and recovered with fast walking or light jogging the second 200 m to the finish line in 3× original sprint time. Maximal oxygen consumption (V[Combining Dot Above]O2max), anaerobic treadmill run to exhaustion at 12.5 km·h at 20% incline, isokinetic leg extension and flexion strength at 60 and 300°·s, and 50 m sprint time were determined before and after training. Results showed a significant improvement (p ≤ 0.05) in absolute and relative V[Combining Dot Above]O2max, anaerobic treadmill run, and sprint time in both groups. Only SITAR showed significant improvements in isokinetic leg extension and flexion at 300°·s and decreases in body mass (p ≤ 0.05). SITAR also showed significantly greater improvement (p ≤ 0.05) over ET in anaerobic treadmill run and 50 m sprint time. These data suggest that SITAR is a time-efficient strategy to induce rapid adaptations in V[Combining Dot Above]O2max comparable to ET with added improvements in anaerobic power, isokinetic strength, and sprint time not observed with ET.

Effects of isocaloric carbohydrate vs. carbohydrate-protein supplements on cycling time to exhaustion.

The purpose of this study was to investigate the effects of isocaloric carbohydrate (CHO) and carbohydrate-protein (CHO-Pro) supplements on time to exhaustion. Eleven moderately aerobically fit adults (V[Combining Dot Above]O2max= 48.3 ± 6.5 ml·kg·min) performed a maximal cycle ergometer test for the determination of V[Combining Dot Above]O2max. At least 72 hours later, the participants performed a time-to-exhaustion test at a power output equivalent to the power output when subjects were at 75% of their V[Combining Dot Above]O2max. Either the CHO or the CHO-Pro supplement was administered at 0, 30, 60, 90, and 120 minutes after this test. After 3 hours of recovery and supplement ingestion, a second time-to-exhaustion test was performed. This testing protocol was repeated for the third visit, but the supplement not given during the second visit was administered. The results indicated that there was no significant difference in time to exhaustion after isocaloric CHO (pretest 22.4 ± 2.84 minutes, posttest 25.4 ± 4.45 minutes) and CHO-Pro (pretest 22.3 ± 3.46 minutes, posttest 24.0 ± 5.08 minutes) supplementation. Carbohydrate and CHO-Pro ingestion after exercise appear to have similar effects on short-term recovery.

Validity of field expedient devices to assess core temperature during exercise in the cold.

INTRODUCTION: Exposure to cold environments affects human performance and physiological function. Major medical organizations recommend rectal temperature (TREC) to evaluate core body temperature (TcORE) during exercise in the cold; however, other field expedient devices claim to measure TCORE. The purpose of this study was to determine if field expedient devices provide valid measures of TcRE during rest and exercise in the cold. METHODS: Participants included 13 men and 12 women (age = 24 +/- 3 yr, height = 170.7 +/- 10.6 cm, mass = 73.4 +/- 16.7 kg, body fat = 18 +/- 7%) who reported being healthy and at least recreationally active. During 150 min of cold exposure, subjects sequentially rested for 30 min, cycled for 90 min (heart rate = 120-140 bpm), and rested for an additional 30 min. Investigators compared aural (T(AUR)), expensive axillary (T(AXLe)), inexpensive axillary (T(AXLi)), forehead (T(FOR)), gastrointestinal (T(GI)), expensive oral (T(ORLe)), inexpensive oral (T(ORLi)), and temporal (T(TEM)) temperatures to T(REc) every 15 min. Researchers used mean difference between each device and T(REC) (i.e., mean bias) as the primary criterion for validity. RESULTS: T(AUR), T(AXLe), T(AXLi), T(FOR), TORLe, T(ORLi), and TTEM provided significantly lower measures compared to T(REC) and fell below our validity criterion. T(GI) significantly exceeded T(REC) at three of eleven time points, but no significant difference existed between mean T(REC) and T(GI) across time. Only T(GI) achieved our validity criterion and compared favorably to T(REC). CONCLUSION: T(GI) offers a valid measurement with which to assess T(CORE) during rest and exercise in the cold; athletic trainers, mountain rescuers, and military medical personnel should avoid other field expedient devices in similar conditions.

Comparison of swim recovery and muscle stimulation on lactate removal after sprint swimming.

Competitive swimming requires multiple bouts of high-intensity exercise, leading to elevated blood lactate. Active exercise recovery has been shown to lower lactate faster than passive resting recovery but may not always be practical. An alternative treatment, electrical muscle stimulation, may have benefits similar to active recovery in lowering blood lactate but to date is unstudied. Therefore, this study compared submaximal swimming and electrical muscle stimulation in reducing blood lactate after sprint swimming. Thirty competitive swimmers (19 men and 11 women) participated in the study. Each subject completed 3 testing sessions consisting of a warm-up swim, a 200-yard maximal frontcrawl sprint, and 1 of 3 20-minute recovery treatments administered in random order. The recovery treatments consisted of a passive resting recovery, a submaximal swimming recovery, or electrical muscle stimulation. Blood lactate was tested at baseline, after the 200-yard sprint, and after 10 and 20 minutes of recovery. A significant interaction (p < 0.05) between recovery treatment and recovery time was observed. Blood lactate levels for the swimming recovery were significantly lower at 10 minutes (3.50 +/- 1.57 mmol.L-1) and 20 minutes (1.60 +/- 0.57 mmol.L-1) of recovery than either of the other 2 treatments. Electrical muscle stimulation led to a lower mean blood lactate (3.12 +/- 1.41 mmol.L-1) after 20 minutes of recovery compared with passive rest (4.11 +/- 1.35 mmol.L-1). Submaximal swimming proved to be most effective at lowering blood lactate, but electrical muscle stimulation also reduced blood lactate 20 minutes postexercise significantly better than resting passive recovery. Electrical muscle stimulation shows promise as an alternate recovery treatment for the purpose of lowering blood lactate.

The effects of stability ball training on spinal stability in sedentary individuals.

Stability ball training (SBT) is believed to improve spinal stability (SS) and could reduce the risk of back pain in sedentary individuals. The purpose of this study was to examine the effects of SBT on SS. Twenty sedentary individuals were randomly assigned to either an experimental group that performed SBT twice per week for 10 weeks or to a control group. Differences between groups were assessed by analysis of variance (ANOVA) with repeated measures. The experimental group improved significantly (p < 0.05) on the static back-endurance test from pretest (149.3 +/- 72.3 seconds) to posttest (194.6 +/- 56.7 seconds) and the side bridge test from pretest (45.4 +/- 39.4 seconds) to posttest (71.3 +/- 59.7 seconds). Back endurance for the control group did not change from pretest (123.4 +/- 64.9 seconds) to posttest (87.5 +/- 40.2 seconds), nor did the results of the side bridge test change for this group from pretest (41.8 +/- 26.4 seconds) to posttest (51.6 +/- 35.9 seconds). These findings illustrate that SBT may provide improvements in SS within this population. Practitioners might use SBT exercises where the position of the spine is maintained during the early phases of back-pain prevention programs. This type of programming might be beneficial to individuals who spend a good deal of time sitting (i.e., in corporate fitness programs) or for individuals who are prone to back pain and have been cleared to exercise. Also, the side bridge and static back endurance assessments may be good choices for measuring SS in field settings.