Hand grip strength (HGS) measures the maximum force generated by the muscles of the hand and forearm. This simple, non-invasive test is a powerful indicator of overall physiological health. It serves as a quick biomarker, offering insights into general body strength, muscle mass, and biological aging. Understanding normal grip strength helps gauge long-term vitality and health prospects.
Measuring Hand Grip Strength
Hand grip strength measurement relies on a standardized protocol for accurate results. The instrument most commonly used is the hydraulic hand dynamometer, often the Jamar model, which measures isometric force. The measurement is typically recorded in kilograms (kg) or occasionally in pounds (lbs) of force.
A standardized test requires the individual to be seated with the shoulder tucked into the side and the elbow bent to a 90-degree angle. The forearm is held in a neutral position, and the wrist remains straight. This posture minimizes the influence of other muscle groups, isolating the strength generated by the hand and forearm.
The handle of the dynamometer is adjusted to fit the individual’s hand size, ensuring it rests on the four fingers and the base of the palm. The person is instructed to squeeze the device with maximum effort for a brief moment, typically three to five seconds. To establish a reliable score, the test is repeated three times for each hand, alternating sides with a short rest period. The highest reading from the dominant hand is often used for comparison against population averages.
Reference Values for Normal Strength
Determining a single “normal” hand grip strength is not possible, as the expected value is heavily dependent on several demographic factors. The most significant variables that stratify the data are age, biological sex, and hand dominance. Strength levels tend to increase through early adulthood, generally peaking between the ages of 25 and 39, and then gradually decline over time.
Reference values are often presented as percentiles, comparing an individual’s score to peers in the same age and sex group. For example, the 50th percentile means an individual’s strength is greater than half of the people in their demographic. A score falling below the 20th percentile is frequently used in clinical settings as a cutoff point indicating low muscle strength.
Men consistently exhibit higher absolute grip strength values than women across all age brackets, reflecting differences in average muscle mass. Furthermore, the dominant hand is usually stronger than the non-dominant hand, often by about 10 percent. For a man in his 30s, a normal grip strength might fall in the range of 48 to 55 kilograms, while a woman of the same age would typically score lower, perhaps ranging from 28 to 35 kilograms.
As people age, a man in his late 60s is expected to score around 35 to 40 kilograms, and a woman around 20 to 25 kilograms. Comparing an individual’s score to normative data tables allows healthcare providers to assess their physical status relative to their peers.
Grip Strength as a Key Health Predictor
Hand grip strength is recognized as a powerful predictor of overall health outcomes. Research suggests that HGS acts as a proxy measurement for total body muscle mass and general physical function. Low strength is a well-established sign of frailty, characterized by reduced physical reserve and increased vulnerability to adverse health events.
A decline in HGS is one of the primary diagnostic criteria for sarcopenia, the age-related loss of muscle mass and function. Since the test is quick, it serves as an early screening tool to identify individuals at risk for this condition. Detecting low strength early allows for timely intervention to prevent further deterioration and loss of functional independence.
The predictive power of HGS is particularly strong concerning cardiovascular health and mortality. Studies have demonstrated an inverse relationship, where lower grip strength is associated with a higher risk of heart attack, stroke, and other cardiovascular diseases. In a large population study, every 5-kilogram decrease in HGS was linked to an increased risk of all-cause mortality, sometimes making it a more reliable predictor of early death than blood pressure.
This association is linked to stronger muscles correlating with better metabolic health, reduced systemic inflammation, and improved arterial function. Low HGS has also been correlated with an increased risk of cognitive decline and complications following surgery. This measurement provides insight into the body’s physiological resilience.
Maintaining and Improving Grip Strength
A proactive approach to physical activity can help maintain grip strength well into later life and potentially improve it. Strengthening the grip involves engaging in specific resistance exercises that target the muscles of the hand, wrist, and forearm. These exercises should address the three main types of grip: crush, support, and pinch.
Crush Grip
Crush grip can be trained by squeezing a hand gripper or a firm stress ball, focusing on a slow, controlled squeeze and release.
Support Grip
To build support grip, which is the ability to hold onto an object for an extended period, exercises like the Farmer’s Carry are effective. This involves walking for a set distance or time while holding the heaviest pair of dumbbells or kettlebells possible.
Pinch Grip
The pinch grip, involving the thumb and fingers, can be strengthened by performing plate pinches, where a weight plate is held between the thumb and fingertips.
General resistance training, such as deadlifts and pull-ups, naturally engages and strengthens the grip muscles as a secondary benefit. Adequate nutritional support is also necessary for muscle maintenance and growth. Consuming sufficient protein helps provide the building blocks needed to support strength gains.