The decision of whether to sprint before or after lifting weights involves choosing the order of two high-intensity training modalities. Both maximal-effort sprinting and resistance training place a high demand on the body, particularly the nervous system and immediate energy reserves. The sequence is highly consequential, as the fatigue induced by the first exercise will compromise the performance and training adaptations of the second. Understanding the physiological consequences of each activity helps determine the optimal workout structure for specific fitness goals.
Prioritizing Resistance Training: Lifting First
When the training objective is to maximize strength gains, muscle size (hypertrophy), or the absolute load lifted, resistance training should be performed first. Heavy lifting requires the central nervous system (CNS) to be fully rested to recruit the maximum number of muscle fibers for maximal force production. If sprinting precedes lifting, the acute fatigue generated would directly limit the weight that can be handled safely and effectively, compromising the strength stimulus.
Maximal effort sprinting rapidly depletes the body’s most explosive energy source: the phosphocreatine (PCr) system. This energy system provides the adenosine triphosphate (ATP) for immediate, high-power contractions, but its stores are finite. Performing sprints first means these PCr stores are significantly diminished, leaving less fuel available for the high-intensity sets of heavy squats, deadlifts, or presses that demand explosive power.
Lifting weights first ensures the muscles are fresh for executing complex, multi-joint movements with precise technique and maximal load. The quality of the movement and the magnitude of the load are key drivers of long-term strength adaptations. Prioritizing lifting ensures the highest possible training volume and intensity for strength development, which is most sensitive to pre-existing fatigue.
Prioritizing Speed and Power: Sprinting First
If the primary goal is to improve absolute speed, running technique, or explosive power, then sprinting must be performed first. Maximal velocity sprinting is a technically demanding skill that requires a completely fresh and responsive central nervous system. Any existing fatigue, whether from heavy lifting or a previous workout, will cause a measurable decline in sprint performance and form.
Sprinting first ensures that the nervous system can optimally coordinate the rapid, powerful muscle contractions required for true maximal speed. The quality of the movement, not the total volume, dictates the speed adaptation; therefore, as soon as technique or velocity visibly degrades, the sprint portion of the workout should end. If lifting is done beforehand, the residual muscle damage and neuromuscular fatigue would immediately compromise the ability to achieve peak running velocity.
The extreme intensity of maximal sprinting requires the rapid firing of high-threshold motor units, which are most effectively recruited when the CNS is un-fatigued. Even a moderate lifting session could introduce peripheral fatigue, which would dampen the neural drive and prevent the athlete from recruiting the necessary fast-twitch muscle fibers. When prioritizing speed, the focus is on a few high-quality, maximal-effort repetitions, which is only possible with a fresh state.
Determining Your Optimal Workout Sequence
The optimal workout sequence is not fixed but depends entirely on which physical quality you are trying to improve most. The general principle of exercise order is that the exercise most important to your goal should be performed when you are least fatigued. For instance, someone aiming for a personal best in the squat should always lift first, regardless of their desire to sprint afterward.
If your goal centers on strength and muscle mass, lift first, and then perform any conditioning sprints afterward, accepting that the sprint quality will be metabolically challenging but not maximally fast. These conditioning-focused sprints, done after lifting, rely more on the glycolytic system and serve as effective metabolic work rather than true speed development. The sprints are used for energy expenditure, not neuromuscular speed gains.
For those whose goal is pure speed, such as a competitive sprinter, maximal effort sprints should always be done first, followed by a lower-volume, non-fatiguing lifting session. The lifting should focus on power or strength maintenance, avoiding high-volume work that would compromise recovery for the next high-quality speed session.
A highly effective strategy for those pursuing both maximal strength and maximal speed is to separate the two activities by a significant amount of time or place them on entirely different training days. By allowing at least six to eight hours between the two high-demand sessions, or ideally a full day, the nervous system and energy stores have a chance to recover partially or fully. This split approach avoids the interference effect where one activity compromises the desired adaptation of the other.