Table 1.
Overview of milk and dairy product studies on exercise performance and recovery of muscle function
| Study | No. of participants (sex) | Age (years) mean ± SD | Fitness level | Design | Groups | Exercise intervention | Milk or placebo ingestion | Study outcomes | Results |
|---|---|---|---|---|---|---|---|---|---|
| Milk and acute resistance/high-intensity exercise | |||||||||
| Rankin et al. [28] | 18 (females) | 22 ± 3 | Team sport athletes | Between-group design | ● Cow’s low-fat milk (1%) ● Placebo energy-matched carbohydrate solution beverage (glucose and an available orange-flavored fruit cordial mixed with water) |
Repeated running sprint protocol (15 × 20 m sprints) plus 8 sets of 10 plyometric jumps | 500 mL immediately after the exercise. The volume of placebo was similar to the intervention one | i) peak torque of the best repetition (dominant leg); ii) RFD; iii) CMJ; iv) RSI; v) 5, 10 and 20-m sprint tests; vi) CK; vii) hsCRP; viii) passive and active VAS muscle soreness | ● Cow’s milk attenuated losses in peak torque (at 60 and 180°/s for extension and flexion), CMJ, and RFD ● No effects were shown for RSI, 10 and 20-m sprints tests, VAS muscle soreness, CK and hsCRP. |
| Rankin et al. [27] | 10 (females) | 22 ± 2 | Team sport athletes | Crossover design | ● Cow’s low-fat milk (1%) ● Placebo energy-matched carbohydrate solution beverage (glucose and an available orange-flavored fruit cordial mixed with water) |
Cycling intermittent sprint protocol (5 min warm-up, 2 x [14 × 2 min bout of exercise comprising of 10 s of passive rest, 5 s of maximal sprinting and 105 s of active recovery, with a 15 s maximal sprint followed by 1 min active recovery after the 7th and 14th 2 min bout). The exercise bouts were separated by a 10 min rest | 500 mL immediately after the exercise. The volume of placebo was similar to the intervention one | i) peak torque of the best repetition (dominant leg); ii) RFD; iii) CMJ; iv) 20-m sprint test; v) CK; vi) hsCRP; vii) PC; viii) passive and active VAS muscle soreness | ● Cow’s milk improved recovery of muscle function (peak torque, RFD, 20-m sprint and CMJ), inflammation and markers of muscle damage (CK, hsCRP, PC). |
| Rankin et al. [29] | 32 (16 females, 16 males) | 24 ± 4 | Team sport athletes | Between-group design | ● Cow’s low-fat milk (1%) ● Placebo energy-matched carbohydrate solution beverage (glucose and an available orange-flavored fruit cordial mixed with water) |
Exercise inducing muscle damage in the hamstrings using isokinetic dynamometry (6 sets of 10 repetitions, eccentric and concentric contractions, with 90 s of rest between sets) at an angular speed of 60°/s | 500 mL immediately after the exercise. The volume of placebo was similar to the intervention one | i) peak torque of the best repetition (dominant leg); ii) 20-m sprint; iii) CMJ; iv) CK; v) sTnI; vi) passive and active VAS muscle soreness | ● Cow’s milk attenuated the decreases in peak torque and 20-m sprint and blunted the increases in passive and active VAS muscle soreness in females compared with a carbohydrate drink. ● Cow’s milk also attenuated increases in sTnI, and a similar effect on serum CK was only observed from 24 to 72 h and 48–72 h. ● In men, cow’s milk produced a minimal positive effect on soreness and muscle damage (sTnI and CK). |
| Cockburn et al. [32] | 14 (males) | 24 ± 4 | Team sport athletes (semiprofessional soccer players) | Between-group design | ● Cow’s emiskimmed milk (1.7%) ● Placebo beverage (water) |
Exercise inducing muscle damage in the hamstrings using isokinetic dynamometry (6 sets of 10 repetitions, eccentric and concentric contractions, with 90 s of rest between sets) at a speed of 1.05 rad/s | 500 mL immediately after the exercise. The volume of placebo was similar to the intervention one | i) CMJ; ii) RSI; iii) 15-m sprint test; iv) agility time; v) Loughborough Intermittent Shuttle Test; vi) CK; vii) Mb; viii) Passive and active VAS muscle soreness | ● Cow’s milk improved performance on 15-m sprint test, agility time and mean 15-m sprint performance. ● There was no effect on CMJ, RSI, serum CK, serum Mb, and active and passive muscle soreness. |
| Cockburn et al. [30] | 24 (males) | 21 ± 3 | Regularly competed in a variety of sports (team and individual) | Between-group design | ● Cow’s semiskimmed milk (1.7%; 500 mL) ● Cow’s semiskimmed milk (1.7%; 1000 mL) ● Placebo beverage (water) |
Exercise inducing muscle damage in the hamstrings using isokinetic dynamometry (6 sets of 10 repetitions, eccentric and concentric contractions, with 90 s of rest between sets) at a speed of 1.05 rad/s | 500 mL or 1000 mL immediately after the exercise. The volume of placebo was 1000 mL | i) Peak torque of the best repetition (dominant leg); ii) CK; iii) Mb; iv) IL-6; v) Passive and active VAS muscle soreness | ● Decrements in isokinetic muscle performance of the dominant leg and CK increases were minimized with the consumption of 500 mL of cow’s milk. ● 1000 mL of cow’s milk could blunt the increase in IL-6; however, no differences between the cow’s milk groups were observed. No other effects were observed. |
| Cockburn et al. [31] | 24 (males) | 21 ± 3 | Regularly competed in team sports (football, rugby, hockey and cricket) | Between-group design | ● Cow’s semiskimmed milk (1.7%) ● Low-fat chocolate milk ● Carbohydrate beverage ● Placebo beverage (water) |
Exercise inducing muscle damage in the hamstrings using isokinetic dynamometry (6 sets of 10 repetitions, eccentric and concentric contractions, with 90 s of rest between sets) at a speed of 1.05 rad/s | 500 mL on two occasions, immediately after and within 2 h after the exercise (total volume: 1000 mL). The volume of placebo was similar to the intervention one | i) peak torque of the best repetition (dominant leg); ii) CK; iii) Mb; iv) passive and active VAS muscle soreness | ● Cow’s milk attenuated the decrements (48 h) in total work of the set, peak torque, CK and Mb after a bout of exercise-induced muscle damage. ● The muscle soreness assessed using VAS was similar between the groups. |
| Kirk et al. [33] | 21 (males) | 23 ± 3 | Regularly competed in team sports (Gaelic football, soccer, rugby) | Between-group design | ● A2 milk ● Regular milk (cow’s milk) ● Placebo beverage (maltodextrin mixed with water) |
Repeated sprint protocol (15 × 30 m sprints with 60 s of rest between series) | 500 mL immediately after the exercise. The volume of placebo was similar to the intervention one | i) CMJ; ii) MVCs; iii) 20-m sprint test; iv) VAS muscle soreness | ● CMJ recovered quicker in both cow’s milk groups vs. the placebo group. No differences between groups were observed in either MVCs or VAS muscle soreness. ● There were no effects on 20-m sprint test time; however, the cow’s milk group recovered quicker than the placebo group. Moreover, relative to the baseline, decrements over 48 h were minimized in the cow’s milk vs. placebo groups. |
| Milk and resistance exercise intervention | |||||||||
| Volek et al. [37] | 28 (males) | 13 to 17 | Not reported | Between-group design | ● Cow’s fluid milk (1%) ● Placebo beverage (apple juice or grape juice depending on the week of study) |
12 weeks of resistance training (1 h, 3 days/week). The program consisted of varying training loads and intensities each week, with concomitant decreasing volume | 708 mL daily (plus their habitual diet). The volume of placebo was similar to the intervention one | i) RM of squat and bench press | ● No differences in maximal strength (squat and bench press strength) were found between groups. |
| Milk and acute endurance exercise | |||||||||
| Upshaw et al. [34] | 8 (males) | 22 ± 2 | Trained cyclists | Crossover design | ● Cow’s low-fat milk (1%) ● Chocolate Milk (1%) ● Hemp chocolate milk ● Soy chocolate milk ● Placebo beverage (low-energy drink) |
Cycling at different intensities until the participant could not continue with the appropriate cadence at an intensity of 70 and 50% of maximal power output. Afterward, a best-effort 20-km time trial test (cycloergometer) | 2262 ± 148 mL (beverage plus water if applicable) immediately after the exercise and at 30 min intervals over 2 h before completing the 20-km time trial test exercise. The volume of placebo was similar to the intervention one | i) best effort 20-km time trial test; ii) HR | ● Cow’s low-fat milk improved the 20-km time trial test performance vs. that of the placebo group. ● No differences in HR were observed during this test. |
| Lee et al. [36] | 8 (males) | 24 ± 4 | Actives (regular physical activity) | Crossover design | ● Cow’s 0.1% fat milk ● Cow’s 0.1% fat milk plus glucose ● A commercially available CHO-electrolyte sports drink ● Placebo beverage (water) |
Continuous cycling exercise at an intensity of 70% VO2peak until volitional exhaustion, defined as an inability to maintain a pedal cadence of ≥60 rpm | 1022 ± 470 (1.5 mL/kg of body mass) every 10 min during exercise. The volume of placebo was similar to the intervention one | i) time to volitional exhaustion (exercise capacity); ii) HR; iii) expired gases; iv) RPE | ● Exercise capacity, basal HR, exercise HR, expired gases and RPE were similar between groups. |
| Watson et al. [35] | 7 (males) | 23 ± 3 | Actives (regular physical activity) | Crossover design | ● Cow’s skimmed milk (1%) ● Placebo beverage (a commercially available carbohydrate-electrolyte drink) |
Series of 10 min cycle (55 ± 6 VO2peak) with 5 min of resting between series, until the loss of approximately 1.8% of the initial body mass. Time to exhaustion (61 ± 4 VO2peak) | 2263 ± 241 mL (150% of the body mass lost) during the exercise, in four equal boluses at 15 min intervals. The volume of placebo was similar to the intervention one | i) exercise to exhaustion (exercise capacity); ii) HR; iii) RPE | ● No effect on time to exhaustion, VO2 and RPE during exercise were observed. ● HR was higher during the cow’s milk trial than during the carbohydrate trial. |
SD Standard deviation, RFD Rate of force development, CMJ Countermovement jump, RSI Reactive strength index, CK Creatine kinase, hsCRP High-sensitivity C-reactive protein, VAS Visual analogue scales, PC Protein carbonyls, sTnI Skeletal troponin I, Mb Myoglobin, IL-6 Interleukin-6, MVCs Maximal voluntary isometric contractions, rad/s radians per second, RM Maximum repetition, HR Heart rate, RPE Ratio of perceived exertion, VO2 volume of oxygen consumption, VO2peak Peak oxygen uptake, rpm revolutions per minute