John R. Jakeman

A single 10-min bout of cold-water immersion therapy after strenuous plyometric exercise has no beneficial effect on recovery from the symptoms of exercise-induced muscle damage

The purpose of this study was to examine the effectiveness of a single bout of cold-water immersion on recovery from exercise-induced muscle damage. Eighteen physically active female volunteers (age 19.9 (±0.97 years), height 1.66 (±0.05 m), mass 63.7 (±10 kg), completed 10 sets of 10 counter-movement jumps to induce muscle damage and were randomly allocated to a control or treatment group. The treatment group was given a single 10-min bout of lower limb cold-water immersion therapy at 10°C immediately following damage-inducing exercise. Indicators of muscle damage (plasma creatine kinase activity, perceived soreness and maximal voluntary contraction of the quadriceps) were assessed immediately prior to counter-movement jumps, and at 1, 24, 48, 72 and 96 h, following the damaging exercise. Significant (p = 0.05) time effects were recorded on all indicators of muscle damage, but there were no significant group or group × time interaction effects found on any of the measured variables. The results indicate that a single bout of cold-water immersion after a damaging bout of exercise has no beneficial effects on the recovery from exercise-induced muscle damage.

Efficacy of lower limb compression and combined treatment of manual massage and lower limb compression on symptoms of exercise-induced muscle damage in women.

Jakeman, JR, Byrne, C, and Eston, RG. Efficacy of lower limb compression and combined treatment of manual massage and lower limb compression on symptoms of exercise-induced muscle damage in women. J Strength Cond Res 24(11): 3157-3165, 2010-Strategies to manage the symptoms of exercise-induced muscle damage (EIMD) are widespread, though are often based on anecdotal evidence. The aim of this study was to determine the efficacy of a combination of manual massage and compressive clothing and compressive clothing individually as recovery strategies after muscle damage. Thirty-two female volunteers completed 100 plyometric drop jumps and were randomly assigned to a passive recovery (n = 17), combined treatment (n = 7), or compression treatment group (n = 8). Indices of muscle damage (perceived soreness, creatine kinase activity, isokinetic muscle strength, squat jump, and countermovement jump performance) were assessed immediately before and after 1, 24, 48, 72, and 96 hours of plyometric exercise. The compression treatment group wore compressive tights for 12 hours after damage and the combined treatment group received a 30-minute massage immediately after damaging exercise and wore compression stockings for the following 11.5 hours. Plyometric exercise had a significant effect on all indices of muscle damage (p < 0.05). The treatments significantly reduced decrements in isokinetic muscle strength, squat jump performance, and countermovement jump performance and reduced the level of perceived soreness in comparison with the passive recovery group (p < 0.05). The addition of sports massage to compression after muscle damage did not improve performance recovery, with recovery trends being similar in both treatment groups. The treatment combination of massage and compression significantly moderated perceived soreness at 48 and 72 hours after plyometric exercise (p < 0.05) in comparison with the passive recovery or compression alone treatment. The results indicate that the use of lower limb compression and a combined treatment of manual massage with lower limb compression are effective recovery strategies following EIMD. Minimal performance differences between treatments were observed, although the combination treatment may be beneficial in controlling perceived soreness.

Effect of Lower-Limb Compression Clothing on 400-m Sprint Performance

Abstract Faulkner, JA, Gleadon, D, McLaren, J, and Jakeman, JR. Effect of lower-limb compression clothing on 400-m sprint performance. J Strength Cond Res 27(3): 669–676, 2013—This study investigated the effects of wearing a variety of lower-limb compression garments on 400-m sprint performance. Eleven 400-m male runners (23.7 ± 5.7 years, 1.78 ± 0.08 m, and 75.3 ± 10.0 kg) completed six, 400-m running tests on an outdoor, all-weather running track on separate occasions. The participants completed 2 runs with long-length lower-limb compression garments (LG; hip-to-ankle), a combination of short-length lower-limb compression garments (SG; hip-to-knee) with calf compression sleeves (ankle-to-knee), or without compression garments (CON; shorts), in a randomized, counterbalanced order. Overall lap time and 100-m split times, heart rate, and ratings of perceived exertion (RPEs) were measured during the 400-m run. Blood lactate concentration, visual analogue scales for perceived soreness, feeling and arousal, and scales for perceived comfort and tightness when wearing compression garments, were assessed before (preexercise, post–warm-up) and after 400-m performance (post, 4 minutes postexercise, after a warm-down). Statistical analysis revealed no differences between conditions in overall 400-m performance, 100-m split times, or blood lactate concentration (p > 0.05), although there was a trend for an increased rate of blood lactate clearance when wearing compression garments. A significantly lower RPE (p > 0.05) was however observed during LG (13.8 ± 0.9) and SG (13.4 ± 1.1) when compared with CON (14.0 ± 1.0). This study has demonstrated that lower-limb compression garments may lower the effort perception associated with 400-m performance, despite there being no differences in overall athletic performance.

Extremely short duration high-intensity training substantially improves endurance performance in triathletes

High-intensity training (HIT) involving 30-s sprints is an effective training regimen to improve aerobic performance. We tested whether 6-s HITs can improve aerobic performance in triathletes. Six subelite triathletes (age, 40 ± 9 years; weight, 86 ± 11 kg; body mass index, 26 ± 3 kg·m⁻²) took part in cycle HIT and 6 endurance-trained subelite athletes (age, 36 ± 9 years; weight, 82 ± 11 kg; BMI, 26 ± 3 kg·m⁻²) maintained their normal training routine. Before and after 2 weeks of HIT, involving 10 × 6-s sprints or normal activity, participants performed a self-paced 10-km time trial and a time to exhaustion test on a cycle ergometer. Finger prick blood samples were taken throughout the time to exhaustion test to determine blood lactate concentration. Two weeks of HIT resulted in a 10% decrease in self-paced 10-km time trial (p = 0.03) but no significant change in time to exhaustion. The time taken to reach onset of blood lactate accumulation (OBLA, defined as the point where blood lactate reaches 4 mmol·L⁻¹) was significantly increased following 2 weeks of HIT (p = 0.003). The change in time trial performance was correlated to the change in time taken to reach OBLA (R² = 0.63; p = 0.001). We concluded that a very short duration HIT is a very effective training regimen to improve aerobic performance in subelite triathletes and this is associated with a delay in blood lactate build-up.

Impact of time and work: rest ratio matched sprint interval training programmes on performance: A randomised controlled trial

OBJECTIVES The aim of this study was to examine the effects of a short training intervention using two repeated sprint protocols matched for total sprint duration and work:rest ratio. DESIGN Randomised-controlled trial. METHODS Thirty physically active males were randomly allocated to one of two sprint training groups: a 6s group, a 30s group or a non-exercising control. The training groups were matched for work:rest ratio and total sprint time per session, and completed 6 training sessions over a 2-week period. Before and after the 2 week training period, participants completed a VO2max test and a 10km time trial on a cycle ergometer. RESULTS Time trial performance increased significantly by 5.1% in 6s (630±115s to 598±92s; p<0.05) and 6.2% in 30s (579±68s to 543±85s; p<0.05) from baseline testing, but there was no significant change in the control group (p>0.05), and no significant difference between exercise groups (p>0.05). The 6s group increased peak power output by 9.0% (from 1092±263W to 1181±248W; p<0.05) from sprint session 1 to 6, and the 30s group by 20.0% (1041±161W to 1237±159W; p<0.05). CONCLUSIONS This study indicates that both 6 and 30s bouts of repeated sprint exercise, matched for total sprint duration and W:R can improve athletic performance.

Efficacy of a Four-Week Uphill Sprint Training Intervention in Field Hockey Players.

Abstract Jakeman, JR, McMullan, J, and Babraj, JA. Efficacy of a four-week uphill sprint training intervention in field hockey players. J Strength Cond Res 30(10): 2761–2766, 2016—Current evidence increasingly suggests that very short, supramaximal bouts of exercise can have significant health and performance benefits. Most research conducted in the area, however, uses laboratory-based protocols, which can lack ecological validity. The purpose of this study was to examine the effects of a high-intensity sprint training program on hockey-related performance measures. Fourteen semiprofessional hockey players either completed a 4-week high-intensity training (HIT) intervention, consisting of a total of 6 sessions of HIT, which progressively increased in volume (n = 7), or followed their normal training program (Con; n = 7). Straight-line sprint speed, with and without a hockey stick and ball, and slalom sprint speed, with and without a hockey stick and ball, were used as performance indicators. Maximal sprint speed over 22.9 m was also assessed. On completion of the 4-week intervention, straight-line sprint speed improved significantly in the HIT group (∼3%), with no changes in performance for the Con group. Slalom sprint speed, both with and without a hockey ball, was not significantly different after the training program in either group. Maximal sprint speed improved significantly (12.1%) in the HIT group, but there was no significant performance change in the Con group. The findings of this study indicate that a short period of HIT can significantly improve hockey-related performance measures and could be beneficial to athletes and coaches in field settings.

Multiple Sprint Exercise with a Short Deceleration Induces Muscle Damage and Performance Impairment in Young, Physically Active Males

Multiple Sprint Exercise with a Short Deceleration Induces Muscle Damage and Performance Impairment in Young, Physically Active Males The purpose of the present study was to identify whether a bout of high-intensity multiple sprints elicits exercise-induced muscle damage (EIMD) of a similar magnitude to drop jumps. Methods: Ten physically active male volunteers (mean ± SD; 27 ± 3 y, 1.78 ± 0.06 m, 78.4 ± 7.5 kg) completed 10×10 drop jumps (DRP) and a bout of 40×15 m sprints with a 5 m deceleration zone (SPR) in a randomised repeated-measures crossover study. Muscle damage indices (creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), perceptual soreness and affective valence, range of motion and limb girth) and performance markers (vertical jump, agility and sprint performance) were gathered at baseline and 1, 24, 48 and 72 h post exercise. Results: The study findings revealed a significant Test by Time interaction for 15 m sprint performance (P 0.05). Conclusion: This study indicates that a bout of multiple sprints with a short deceleration phase elicits greater reductions in sprint performance than drop jumps. This should be considered by individuals using similar sprint protocols in an applied context and by individuals looking to conduct research into EIMD using ecologically valid exercise protocols.

Early Adaptations to a Two-Week Uphill Run Sprint Interval Training and Cycle Sprint Interval Training

This study sought to compare early physiological and performance adaptations between a two-week cycle sprint interval training (SIT) and uphill run sprint training (UST) programs. Seventeen recreationally active adult males (age = 28 ± 5 years; body mass (BM) = 78 ± 9 kg) were assigned to either a control (n = 5), SIT (n = 6), or UST (n = 6) group. A discrete group of participants (n = 6, age = 33 ± 6 years, and body mass = 80 ± 9 kg) completed both training protocols to determine acute physiological responses. Intervention groups completed either a run or cycle peak oxygen uptake (VO2peak) test (intervention type dependent) prior to and following two weeks of training. Training comprised of three sessions per week of 4 × 30-s “all-out” sprints with a four-minute active recovery between bouts on a cycle ergometer against 7.5% of body mass in the SIT group and on a 10% slope in the UST group. The VO2peak values remained unchanged in both training groups, but time-to-exhaustion (TTE) was significantly increased only in the UST group (pre—495 ± 40 s, post—551 ± 15 s; p = 0.014) and not in the SIT group (pre—613 ± 130 s, post—634 ± 118 s, p = 0.07). Ventilatory threshold (VT) was significantly increased in both training groups (SIT group: pre—1.94 ± 0.45 L·min−1, post—2.23 ± 0.42 L·min−1; p < 0.005, UST group: pre—2.04 ± 0.40 L·min−1, post—2.33 ± 0.34 L·min−1, p < 0.005). These results indicate that UST may be an effective alternative to SIT in healthy individuals.

The efficacy of a discontinuous graded exercise test in measuring peak oxygen uptake in children aged 8 to 10 years

As children’s natural activity patterns are highly intermittent in nature, and characterised by rapid changes from rest to vigorous physical activity, discontinuous exercise tests may be considered ecologically valid for this population group. This study compared the peak physiological responses from a discontinuous and continuous graded exercise test (GXT_D, GXT_C, respectively) during treadmill exercise in children. Twenty-one healthy children (9.6 ± 0.6 y) completed GXT_D and GXT_C in a randomised order, separated by 72-hours. Following each GXT, and after a 15-minute recovery, participants completed a verification test at 105% of the velocity attained at peak oxygen consumption (VO2peak). There were no differences in VO2peak (55.3 ± 8.2 cf. 54.4 ± 7.6 mL·kg-1·min-1) or maximal heart rate (202 ± 10 cf. 204 ± 8 b·min-1) between GXT_C and GXT_D, respectively (P>.05). Peak running speed (10.7 ± 0.9 cf. 12.1 ± 1.3 km·h-1) and respiratory exchange ratio (1.04 ± 0.05 cf. 0.92 ± 0.05) were however different between tests (P<.001). Although similar peak physiological values were revealed between GXT_C and the corresponding verification test (P>.05), VO2peak (53.3 ± 7.3 mL·kg-1·min-1) and heart rate (197 ± 13 b·min-1) were significantly lower in the GXT_D verification test (P<.05). In conclusion, a discontinuous GXT is an accurate measure of VO2peak in children aged 8 to 10 years and may be a valid alternative to a continuous GXT, despite its longer duration.